Rename scripts to build and add revive command as a new build tool command (#10942)

Co-authored-by: techknowlogick <techknowlogick@gitea.io>

vendor/github.com/mgechev/revive/rule/add-constant.go

@@ -0,0 +1,151 @@
+package rule
+
+import (
+	"fmt"
+	"github.com/mgechev/revive/lint"
+	"go/ast"
+	"strconv"
+	"strings"
+)
+
+const (
+	defaultStrLitLimit = 2
+	kindFLOAT          = "FLOAT"
+	kindINT            = "INT"
+	kindSTRING         = "STRING"
+)
+
+type whiteList map[string]map[string]bool
+
+func newWhiteList() whiteList {
+	return map[string]map[string]bool{kindINT: map[string]bool{}, kindFLOAT: map[string]bool{}, kindSTRING: map[string]bool{}}
+}
+
+func (wl whiteList) add(kind string, list string) {
+	elems := strings.Split(list, ",")
+	for _, e := range elems {
+		wl[kind][e] = true
+	}
+}
+
+// AddConstantRule lints unused params in functions.
+type AddConstantRule struct{}
+
+// Apply applies the rule to given file.
+func (r *AddConstantRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
+	strLitLimit := defaultStrLitLimit
+	var whiteList = newWhiteList()
+	if len(arguments) > 0 {
+		args, ok := arguments[0].(map[string]interface{})
+		if !ok {
+			panic(fmt.Sprintf("Invalid argument to the add-constant rule. Expecting a k,v map, got %T", arguments[0]))
+		}
+		for k, v := range args {
+			kind := ""
+			switch k {
+			case "allowFloats":
+				kind = kindFLOAT
+				fallthrough
+			case "allowInts":
+				if kind == "" {
+					kind = kindINT
+				}
+				fallthrough
+			case "allowStrs":
+				if kind == "" {
+					kind = kindSTRING
+				}
+				list, ok := v.(string)
+				if !ok {
+					panic(fmt.Sprintf("Invalid argument to the add-constant rule, string expected. Got '%v' (%T)", v, v))
+				}
+				whiteList.add(kind, list)
+			case "maxLitCount":
+				sl, ok := v.(string)
+				if !ok {
+					panic(fmt.Sprintf("Invalid argument to the add-constant rule, expecting string representation of an integer. Got '%v' (%T)", v, v))
+				}
+
+				limit, err := strconv.Atoi(sl)
+				if err != nil {
+					panic(fmt.Sprintf("Invalid argument to the add-constant rule, expecting string representation of an integer. Got '%v'", v))
+				}
+				strLitLimit = limit
+			}
+		}
+	}
+
+	var failures []lint.Failure
+
+	onFailure := func(failure lint.Failure) {
+		failures = append(failures, failure)
+	}
+
+	w := lintAddConstantRule{onFailure: onFailure, strLits: make(map[string]int, 0), strLitLimit: strLitLimit, whiteLst: whiteList}
+
+	ast.Walk(w, file.AST)
+
+	return failures
+}
+
+// Name returns the rule name.
+func (r *AddConstantRule) Name() string {
+	return "add-constant"
+}
+
+type lintAddConstantRule struct {
+	onFailure   func(lint.Failure)
+	strLits     map[string]int
+	strLitLimit int
+	whiteLst    whiteList
+}
+
+func (w lintAddConstantRule) Visit(node ast.Node) ast.Visitor {
+	switch n := node.(type) {
+	case *ast.GenDecl:
+		return nil // skip declarations
+	case *ast.BasicLit:
+		switch kind := n.Kind.String(); kind {
+		case kindFLOAT, kindINT:
+			w.checkNumLit(kind, n)
+		case kindSTRING:
+			w.checkStrLit(n)
+		}
+	}
+
+	return w
+
+}
+
+func (w lintAddConstantRule) checkStrLit(n *ast.BasicLit) {
+	if w.whiteLst[kindSTRING][n.Value] {
+		return
+	}
+
+	count := w.strLits[n.Value]
+	if count >= 0 {
+		w.strLits[n.Value] = count + 1
+		if w.strLits[n.Value] > w.strLitLimit {
+			w.onFailure(lint.Failure{
+				Confidence: 1,
+				Node:       n,
+				Category:   "style",
+				Failure:    fmt.Sprintf("string literal %s appears, at least, %d times, create a named constant for it", n.Value, w.strLits[n.Value]),
+			})
+			w.strLits[n.Value] = -1 // mark it to avoid failing again on the same literal
+		}
+	}
+}
+
+func (w lintAddConstantRule) checkNumLit(kind string, n *ast.BasicLit) {
+	if w.whiteLst[kind][n.Value] {
+		return
+	}
+
+	w.onFailure(lint.Failure{
+		Confidence: 1,
+		Node:       n,
+		Category:   "style",
+		Failure:    fmt.Sprintf("avoid magic numbers like '%s', create a named constant for it", n.Value),
+	})
+}

vendor/github.com/mgechev/revive/rule/argument-limit.go

@@ -0,0 +1,67 @@
+package rule
+
+import (
+	"fmt"
+	"go/ast"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// ArgumentsLimitRule lints given else constructs.
+type ArgumentsLimitRule struct{}
+
+// Apply applies the rule to given file.
+func (r *ArgumentsLimitRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
+	if len(arguments) != 1 {
+		panic(`invalid configuration for "argument-limit"`)
+	}
+
+	total, ok := arguments[0].(int64) // Alt. non panicking version
+	if !ok {
+		panic(`invalid value passed as argument number to the "argument-list" rule`)
+	}
+
+	var failures []lint.Failure
+
+	walker := lintArgsNum{
+		total: int(total),
+		onFailure: func(failure lint.Failure) {
+			failures = append(failures, failure)
+		},
+	}
+
+	ast.Walk(walker, file.AST)
+
+	return failures
+}
+
+// Name returns the rule name.
+func (r *ArgumentsLimitRule) Name() string {
+	return "argument-limit"
+}
+
+type lintArgsNum struct {
+	total     int
+	onFailure func(lint.Failure)
+}
+
+func (w lintArgsNum) Visit(n ast.Node) ast.Visitor {
+	node, ok := n.(*ast.FuncDecl)
+	if ok {
+		num := 0
+		for _, l := range node.Type.Params.List {
+			for range l.Names {
+				num++
+			}
+		}
+		if num > w.total {
+			w.onFailure(lint.Failure{
+				Confidence: 1,
+				Failure:    fmt.Sprintf("maximum number of arguments per function exceeded; max %d but got %d", w.total, num),
+				Node:       node.Type,
+			})
+			return w
+		}
+	}
+	return w
+}

vendor/github.com/mgechev/revive/rule/atomic.go

@@ -0,0 +1,94 @@
+package rule
+
+import (
+	"go/ast"
+	"go/token"
+	"go/types"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// AtomicRule lints given else constructs.
+type AtomicRule struct{}
+
+// Apply applies the rule to given file.
+func (r *AtomicRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+	walker := atomic{
+		pkgTypesInfo: file.Pkg.TypesInfo,
+		onFailure: func(failure lint.Failure) {
+			failures = append(failures, failure)
+		},
+	}
+
+	ast.Walk(walker, file.AST)
+
+	return failures
+}
+
+// Name returns the rule name.
+func (r *AtomicRule) Name() string {
+	return "atomic"
+}
+
+type atomic struct {
+	pkgTypesInfo *types.Info
+	onFailure    func(lint.Failure)
+}
+
+func (w atomic) Visit(node ast.Node) ast.Visitor {
+	n, ok := node.(*ast.AssignStmt)
+	if !ok {
+		return w
+	}
+
+	if len(n.Lhs) != len(n.Rhs) {
+		return nil // skip assignment sub-tree
+	}
+	if len(n.Lhs) == 1 && n.Tok == token.DEFINE {
+		return nil // skip assignment sub-tree
+	}
+
+	for i, right := range n.Rhs {
+		call, ok := right.(*ast.CallExpr)
+		if !ok {
+			continue
+		}
+		sel, ok := call.Fun.(*ast.SelectorExpr)
+		if !ok {
+			continue
+		}
+		pkgIdent, _ := sel.X.(*ast.Ident)
+		if w.pkgTypesInfo != nil {
+			pkgName, ok := w.pkgTypesInfo.Uses[pkgIdent].(*types.PkgName)
+			if !ok || pkgName.Imported().Path() != "sync/atomic" {
+				continue
+			}
+		}
+
+		switch sel.Sel.Name {
+		case "AddInt32", "AddInt64", "AddUint32", "AddUint64", "AddUintptr":
+			left := n.Lhs[i]
+			if len(call.Args) != 2 {
+				continue
+			}
+			arg := call.Args[0]
+			broken := false
+
+			if uarg, ok := arg.(*ast.UnaryExpr); ok && uarg.Op == token.AND {
+				broken = gofmt(left) == gofmt(uarg.X)
+			} else if star, ok := left.(*ast.StarExpr); ok {
+				broken = gofmt(star.X) == gofmt(arg)
+			}
+
+			if broken {
+				w.onFailure(lint.Failure{
+					Confidence: 1,
+					Failure:    "direct assignment to atomic value",
+					Node:       n,
+				})
+			}
+		}
+	}
+	return w
+}

vendor/github.com/mgechev/revive/rule/bare-return.go

@@ -0,0 +1,84 @@
+package rule
+
+import (
+	"go/ast"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// BareReturnRule lints given else constructs.
+type BareReturnRule struct{}
+
+// Apply applies the rule to given file.
+func (r *BareReturnRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	onFailure := func(failure lint.Failure) {
+		failures = append(failures, failure)
+	}
+
+	w := lintBareReturnRule{onFailure: onFailure}
+	ast.Walk(w, file.AST)
+	return failures
+}
+
+// Name returns the rule name.
+func (r *BareReturnRule) Name() string {
+	return "bare-return"
+}
+
+type lintBareReturnRule struct {
+	onFailure func(lint.Failure)
+}
+
+func (w lintBareReturnRule) Visit(node ast.Node) ast.Visitor {
+	switch n := node.(type) {
+	case *ast.FuncDecl:
+		w.checkFunc(n.Type.Results, n.Body)
+	case *ast.FuncLit: // to cope with deferred functions and go-routines
+		w.checkFunc(n.Type.Results, n.Body)
+	}
+
+	return w
+}
+
+// checkFunc will verify if the given function has named result and bare returns
+func (w lintBareReturnRule) checkFunc(results *ast.FieldList, body *ast.BlockStmt) {
+	hasNamedResults := results != nil && len(results.List) > 0 && results.List[0].Names != nil
+	if !hasNamedResults || body == nil {
+		return // nothing to do
+	}
+
+	brf := bareReturnFinder{w.onFailure}
+	ast.Walk(brf, body)
+}
+
+type bareReturnFinder struct {
+	onFailure func(lint.Failure)
+}
+
+func (w bareReturnFinder) Visit(node ast.Node) ast.Visitor {
+	_, ok := node.(*ast.FuncLit)
+	if ok {
+		// skip analysing function literals
+		// they will analyzed by the lintBareReturnRule.Visit method
+		return nil
+	}
+
+	rs, ok := node.(*ast.ReturnStmt)
+	if !ok {
+		return w
+	}
+
+	if len(rs.Results) > 0 {
+		return w
+	}
+
+	w.onFailure(lint.Failure{
+		Confidence: 1,
+		Node:       rs,
+		Failure:    "avoid using bare returns, please add return expressions",
+	})
+
+	return w
+}

vendor/github.com/mgechev/revive/rule/blank-imports.go

@@ -0,0 +1,74 @@
+package rule
+
+import (
+	"go/ast"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// BlankImportsRule lints given else constructs.
+type BlankImportsRule struct{}
+
+// Apply applies the rule to given file.
+func (r *BlankImportsRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	fileAst := file.AST
+	walker := lintBlankImports{
+		file:    file,
+		fileAst: fileAst,
+		onFailure: func(failure lint.Failure) {
+			failures = append(failures, failure)
+		},
+	}
+
+	ast.Walk(walker, fileAst)
+
+	return failures
+}
+
+// Name returns the rule name.
+func (r *BlankImportsRule) Name() string {
+	return "blank-imports"
+}
+
+type lintBlankImports struct {
+	fileAst   *ast.File
+	file      *lint.File
+	onFailure func(lint.Failure)
+}
+
+func (w lintBlankImports) Visit(_ ast.Node) ast.Visitor {
+	// In package main and in tests, we don't complain about blank imports.
+	if w.file.Pkg.IsMain() || w.file.IsTest() {
+		return nil
+	}
+
+	// The first element of each contiguous group of blank imports should have
+	// an explanatory comment of some kind.
+	for i, imp := range w.fileAst.Imports {
+		pos := w.file.ToPosition(imp.Pos())
+
+		if !isBlank(imp.Name) {
+			continue // Ignore non-blank imports.
+		}
+		if i > 0 {
+			prev := w.fileAst.Imports[i-1]
+			prevPos := w.file.ToPosition(prev.Pos())
+			if isBlank(prev.Name) && prevPos.Line+1 == pos.Line {
+				continue // A subsequent blank in a group.
+			}
+		}
+
+		// This is the first blank import of a group.
+		if imp.Doc == nil && imp.Comment == nil {
+			w.onFailure(lint.Failure{
+				Node:       imp,
+				Failure:    "a blank import should be only in a main or test package, or have a comment justifying it",
+				Confidence: 1,
+				Category:   "imports",
+			})
+		}
+	}
+	return nil
+}

vendor/github.com/mgechev/revive/rule/bool-literal-in-expr.go

@@ -0,0 +1,73 @@
+package rule
+
+import (
+	"go/ast"
+	"go/token"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// BoolLiteralRule warns when logic expressions contains Boolean literals.
+type BoolLiteralRule struct{}
+
+// Apply applies the rule to given file.
+func (r *BoolLiteralRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	onFailure := func(failure lint.Failure) {
+		failures = append(failures, failure)
+	}
+
+	astFile := file.AST
+	w := &lintBoolLiteral{astFile, onFailure}
+	ast.Walk(w, astFile)
+
+	return failures
+}
+
+// Name returns the rule name.
+func (r *BoolLiteralRule) Name() string {
+	return "bool-literal-in-expr"
+}
+
+type lintBoolLiteral struct {
+	file      *ast.File
+	onFailure func(lint.Failure)
+}
+
+func (w *lintBoolLiteral) Visit(node ast.Node) ast.Visitor {
+	switch n := node.(type) {
+	case *ast.BinaryExpr:
+		if !isBoolOp(n.Op) {
+			return w
+		}
+
+		lexeme, ok := isExprABooleanLit(n.X)
+		if !ok {
+			lexeme, ok = isExprABooleanLit(n.Y)
+
+			if !ok {
+				return w
+			}
+		}
+
+		isConstant := (n.Op == token.LAND && lexeme == "false") || (n.Op == token.LOR && lexeme == "true")
+
+		if isConstant {
+			w.addFailure(n, "Boolean expression seems to always evaluate to "+lexeme, "logic")
+		} else {
+			w.addFailure(n, "omit Boolean literal in expression", "style")
+		}
+	}
+
+	return w
+}
+
+func (w lintBoolLiteral) addFailure(node ast.Node, msg string, cat string) {
+	w.onFailure(lint.Failure{
+		Confidence: 1,
+		Node:       node,
+		Category:   cat,
+		Failure:    msg,
+	})
+}

vendor/github.com/mgechev/revive/rule/call-to-gc.go

@@ -0,0 +1,70 @@
+package rule
+
+import (
+	"go/ast"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// CallToGCRule lints calls to the garbage collector.
+type CallToGCRule struct{}
+
+// Apply applies the rule to given file.
+func (r *CallToGCRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+	onFailure := func(failure lint.Failure) {
+		failures = append(failures, failure)
+	}
+
+	var gcTriggeringFunctions = map[string]map[string]bool{
+		"runtime": map[string]bool{"GC": true},
+	}
+
+	w := lintCallToGC{onFailure, gcTriggeringFunctions}
+	ast.Walk(w, file.AST)
+
+	return failures
+}
+
+// Name returns the rule name.
+func (r *CallToGCRule) Name() string {
+	return "call-to-gc"
+}
+
+type lintCallToGC struct {
+	onFailure             func(lint.Failure)
+	gcTriggeringFunctions map[string]map[string]bool
+}
+
+func (w lintCallToGC) Visit(node ast.Node) ast.Visitor {
+	ce, ok := node.(*ast.CallExpr)
+	if !ok {
+		return w // nothing to do, the node is not a call
+	}
+
+	fc, ok := ce.Fun.(*ast.SelectorExpr)
+	if !ok {
+		return nil // nothing to do, the call is not of the form pkg.func(...)
+	}
+
+	id, ok := fc.X.(*ast.Ident)
+
+	if !ok {
+		return nil // in case X is not an id (it should be!)
+	}
+
+	fn := fc.Sel.Name
+	pkg := id.Name
+	if !w.gcTriggeringFunctions[pkg][fn] {
+		return nil // it isn't a call to a GC triggering function
+	}
+
+	w.onFailure(lint.Failure{
+		Confidence: 1,
+		Node:       node,
+		Category:   "bad practice",
+		Failure:    "explicit call to the garbage collector",
+	})
+
+	return w
+}

vendor/github.com/mgechev/revive/rule/cognitive-complexity.go

@@ -0,0 +1,195 @@
+package rule
+
+import (
+	"fmt"
+	"go/ast"
+	"go/token"
+
+	"github.com/mgechev/revive/lint"
+	"golang.org/x/tools/go/ast/astutil"
+)
+
+// CognitiveComplexityRule lints given else constructs.
+type CognitiveComplexityRule struct{}
+
+// Apply applies the rule to given file.
+func (r *CognitiveComplexityRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	const expectedArgumentsCount = 1
+	if len(arguments) < expectedArgumentsCount {
+		panic(fmt.Sprintf("not enough arguments for cognitive-complexity, expected %d, got %d", expectedArgumentsCount, len(arguments)))
+	}
+	complexity, ok := arguments[0].(int64)
+	if !ok {
+		panic(fmt.Sprintf("invalid argument type for cognitive-complexity, expected int64, got %T", arguments[0]))
+	}
+
+	linter := cognitiveComplexityLinter{
+		file:          file,
+		maxComplexity: int(complexity),
+		onFailure: func(failure lint.Failure) {
+			failures = append(failures, failure)
+		},
+	}
+
+	linter.lint()
+
+	return failures
+}
+
+// Name returns the rule name.
+func (r *CognitiveComplexityRule) Name() string {
+	return "cognitive-complexity"
+}
+
+type cognitiveComplexityLinter struct {
+	file          *lint.File
+	maxComplexity int
+	onFailure     func(lint.Failure)
+}
+
+func (w cognitiveComplexityLinter) lint() {
+	f := w.file
+	for _, decl := range f.AST.Decls {
+		if fn, ok := decl.(*ast.FuncDecl); ok {
+			v := cognitiveComplexityVisitor{}
+			c := v.subTreeComplexity(fn.Body)
+			if c > w.maxComplexity {
+				w.onFailure(lint.Failure{
+					Confidence: 1,
+					Category:   "maintenance",
+					Failure:    fmt.Sprintf("function %s has cognitive complexity %d (> max enabled %d)", funcName(fn), c, w.maxComplexity),
+					Node:       fn,
+				})
+			}
+		}
+	}
+}
+
+type cognitiveComplexityVisitor struct {
+	complexity   int
+	nestingLevel int
+}
+
+// subTreeComplexity calculates the cognitive complexity of an AST-subtree.
+func (v cognitiveComplexityVisitor) subTreeComplexity(n ast.Node) int {
+	ast.Walk(&v, n)
+	return v.complexity
+}
+
+// Visit implements the ast.Visitor interface.
+func (v *cognitiveComplexityVisitor) Visit(n ast.Node) ast.Visitor {
+	switch n := n.(type) {
+	case *ast.IfStmt:
+		targets := []ast.Node{n.Cond, n.Body, n.Else}
+		v.walk(1, targets...)
+		return nil
+	case *ast.ForStmt:
+		targets := []ast.Node{n.Cond, n.Body}
+		v.walk(1, targets...)
+		return nil
+	case *ast.RangeStmt:
+		v.walk(1, n.Body)
+		return nil
+	case *ast.SelectStmt:
+		v.walk(1, n.Body)
+		return nil
+	case *ast.SwitchStmt:
+		v.walk(1, n.Body)
+		return nil
+	case *ast.TypeSwitchStmt:
+		v.walk(1, n.Body)
+		return nil
+	case *ast.FuncLit:
+		v.walk(0, n.Body) // do not increment the complexity, just do the nesting
+		return nil
+	case *ast.BinaryExpr:
+		v.complexity += v.binExpComplexity(n)
+		return nil // skip visiting binexp sub-tree (already visited by binExpComplexity)
+	case *ast.BranchStmt:
+		if n.Label != nil {
+			v.complexity += 1
+		}
+	}
+	// TODO handle (at least) direct recursion
+
+	return v
+}
+
+func (v *cognitiveComplexityVisitor) walk(complexityIncrement int, targets ...ast.Node) {
+	v.complexity += complexityIncrement + v.nestingLevel
+	nesting := v.nestingLevel
+	v.nestingLevel++
+
+	for _, t := range targets {
+		if t == nil {
+			continue
+		}
+
+		ast.Walk(v, t)
+	}
+
+	v.nestingLevel = nesting
+}
+
+func (cognitiveComplexityVisitor) binExpComplexity(n *ast.BinaryExpr) int {
+	calculator := binExprComplexityCalculator{opsStack: []token.Token{}}
+
+	astutil.Apply(n, calculator.pre, calculator.post)
+
+	return calculator.complexity
+}
+
+type binExprComplexityCalculator struct {
+	complexity    int
+	opsStack      []token.Token // stack of bool operators
+	subexpStarted bool
+}
+
+func (becc *binExprComplexityCalculator) pre(c *astutil.Cursor) bool {
+	switch n := c.Node().(type) {
+	case *ast.BinaryExpr:
+		isBoolOp := n.Op == token.LAND || n.Op == token.LOR
+		if !isBoolOp {
+			break
+		}
+
+		ops := len(becc.opsStack)
+		// if
+		// 		is the first boolop in the expression OR
+		// 		is the first boolop inside a subexpression (...) OR
+		//		is not the same to the previous one
+		// then
+		//      increment complexity
+		if ops == 0 || becc.subexpStarted || n.Op != becc.opsStack[ops-1] {
+			becc.complexity++
+			becc.subexpStarted = false
+		}
+
+		becc.opsStack = append(becc.opsStack, n.Op)
+	case *ast.ParenExpr:
+		becc.subexpStarted = true
+	}
+
+	return true
+}
+
+func (becc *binExprComplexityCalculator) post(c *astutil.Cursor) bool {
+	switch n := c.Node().(type) {
+	case *ast.BinaryExpr:
+		isBoolOp := n.Op == token.LAND || n.Op == token.LOR
+		if !isBoolOp {
+			break
+		}
+
+		ops := len(becc.opsStack)
+		if ops > 0 {
+			becc.opsStack = becc.opsStack[:ops-1]
+		}
+	case *ast.ParenExpr:
+		becc.subexpStarted = false
+	}
+
+	return true
+}

vendor/github.com/mgechev/revive/rule/confusing-naming.go

@@ -0,0 +1,190 @@
+package rule
+
+import (
+	"fmt"
+	"go/ast"
+
+	"strings"
+	"sync"
+
+	"github.com/mgechev/revive/lint"
+)
+
+type referenceMethod struct {
+	fileName string
+	id       *ast.Ident
+}
+
+type pkgMethods struct {
+	pkg     *lint.Package
+	methods map[string]map[string]*referenceMethod
+	mu      *sync.Mutex
+}
+
+type packages struct {
+	pkgs []pkgMethods
+	mu   sync.Mutex
+}
+
+func (ps *packages) methodNames(lp *lint.Package) pkgMethods {
+	ps.mu.Lock()
+
+	for _, pkg := range ps.pkgs {
+		if pkg.pkg == lp {
+			ps.mu.Unlock()
+			return pkg
+		}
+	}
+
+	pkgm := pkgMethods{pkg: lp, methods: make(map[string]map[string]*referenceMethod), mu: &sync.Mutex{}}
+	ps.pkgs = append(ps.pkgs, pkgm)
+
+	ps.mu.Unlock()
+	return pkgm
+}
+
+var allPkgs = packages{pkgs: make([]pkgMethods, 1)}
+
+// ConfusingNamingRule lints method names that differ only by capitalization
+type ConfusingNamingRule struct{}
+
+// Apply applies the rule to given file.
+func (r *ConfusingNamingRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+	fileAst := file.AST
+	pkgm := allPkgs.methodNames(file.Pkg)
+	walker := lintConfusingNames{
+		fileName: file.Name,
+		pkgm:     pkgm,
+		onFailure: func(failure lint.Failure) {
+			failures = append(failures, failure)
+		},
+	}
+
+	ast.Walk(&walker, fileAst)
+
+	return failures
+}
+
+// Name returns the rule name.
+func (r *ConfusingNamingRule) Name() string {
+	return "confusing-naming"
+}
+
+//checkMethodName checks if a given method/function name is similar (just case differences) to other method/function of the same struct/file.
+func checkMethodName(holder string, id *ast.Ident, w *lintConfusingNames) {
+	if id.Name == "init" && holder == defaultStructName {
+		// ignore init functions
+		return
+	}
+
+	pkgm := w.pkgm
+	name := strings.ToUpper(id.Name)
+
+	pkgm.mu.Lock()
+	defer pkgm.mu.Unlock()
+
+	if pkgm.methods[holder] != nil {
+		if pkgm.methods[holder][name] != nil {
+			refMethod := pkgm.methods[holder][name]
+			// confusing names
+			var kind string
+			if holder == defaultStructName {
+				kind = "function"
+			} else {
+				kind = "method"
+			}
+			var fileName string
+			if w.fileName == refMethod.fileName {
+				fileName = "the same source file"
+			} else {
+				fileName = refMethod.fileName
+			}
+			w.onFailure(lint.Failure{
+				Failure:    fmt.Sprintf("Method '%s' differs only by capitalization to %s '%s' in %s", id.Name, kind, refMethod.id.Name, fileName),
+				Confidence: 1,
+				Node:       id,
+				Category:   "naming",
+			})
+
+			return
+		}
+	} else {
+		pkgm.methods[holder] = make(map[string]*referenceMethod, 1)
+	}
+
+	// update the black list
+	if pkgm.methods[holder] == nil {
+		println("no entry for '", holder, "'")
+	}
+	pkgm.methods[holder][name] = &referenceMethod{fileName: w.fileName, id: id}
+}
+
+type lintConfusingNames struct {
+	fileName  string
+	pkgm      pkgMethods
+	onFailure func(lint.Failure)
+}
+
+const defaultStructName = "_" // used to map functions
+
+//getStructName of a function receiver. Defaults to defaultStructName
+func getStructName(r *ast.FieldList) string {
+	result := defaultStructName
+
+	if r == nil || len(r.List) < 1 {
+		return result
+	}
+
+	t := r.List[0].Type
+
+	if p, _ := t.(*ast.StarExpr); p != nil { // if a pointer receiver => dereference pointer receiver types
+		t = p.X
+	}
+
+	if p, _ := t.(*ast.Ident); p != nil {
+		result = p.Name
+	}
+
+	return result
+}
+
+func checkStructFields(fields *ast.FieldList, structName string, w *lintConfusingNames) {
+	bl := make(map[string]bool, len(fields.List))
+	for _, f := range fields.List {
+		for _, id := range f.Names {
+			normName := strings.ToUpper(id.Name)
+			if bl[normName] {
+				w.onFailure(lint.Failure{
+					Failure:    fmt.Sprintf("Field '%s' differs only by capitalization to other field in the struct type %s", id.Name, structName),
+					Confidence: 1,
+					Node:       id,
+					Category:   "naming",
+				})
+			} else {
+				bl[normName] = true
+			}
+		}
+	}
+}
+
+func (w *lintConfusingNames) Visit(n ast.Node) ast.Visitor {
+	switch v := n.(type) {
+	case *ast.FuncDecl:
+		// Exclude naming warnings for functions that are exported to C but
+		// not exported in the Go API.
+		// See https://github.com/golang/lint/issues/144.
+		if ast.IsExported(v.Name.Name) || !isCgoExported(v) {
+			checkMethodName(getStructName(v.Recv), v.Name, w)
+		}
+	case *ast.TypeSpec:
+		if s, ok := v.Type.(*ast.StructType); ok {
+			checkStructFields(s.Fields, v.Name.Name, w)
+		}
+
+	default:
+		// will add other checks like field names, struct names, etc.
+	}
+
+	return w
+}

vendor/github.com/mgechev/revive/rule/confusing-results.go

@@ -0,0 +1,67 @@
+package rule
+
+import (
+	"go/ast"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// ConfusingResultsRule lints given function declarations
+type ConfusingResultsRule struct{}
+
+// Apply applies the rule to given file.
+func (r *ConfusingResultsRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	fileAst := file.AST
+	walker := lintConfusingResults{
+		onFailure: func(failure lint.Failure) {
+			failures = append(failures, failure)
+		},
+	}
+
+	ast.Walk(walker, fileAst)
+
+	return failures
+}
+
+// Name returns the rule name.
+func (r *ConfusingResultsRule) Name() string {
+	return "confusing-results"
+}
+
+type lintConfusingResults struct {
+	onFailure func(lint.Failure)
+}
+
+func (w lintConfusingResults) Visit(n ast.Node) ast.Visitor {
+	fn, ok := n.(*ast.FuncDecl)
+	if !ok || fn.Type.Results == nil || len(fn.Type.Results.List) < 2 {
+		return w
+	}
+	lastType := ""
+	for _, result := range fn.Type.Results.List {
+		if len(result.Names) > 0 {
+			return w
+		}
+
+		t, ok := result.Type.(*ast.Ident)
+		if !ok {
+			return w
+		}
+
+		if t.Name == lastType {
+			w.onFailure(lint.Failure{
+				Node:       n,
+				Confidence: 1,
+				Category:   "naming",
+				Failure:    "unnamed results of the same type may be confusing, consider using named results",
+			})
+			break
+		}
+		lastType = t.Name
+
+	}
+
+	return w
+}

vendor/github.com/mgechev/revive/rule/constant-logical-expr.go

@@ -0,0 +1,88 @@
+package rule
+
+import (
+	"github.com/mgechev/revive/lint"
+	"go/ast"
+	"go/token"
+)
+
+// ConstantLogicalExprRule warns on constant logical expressions.
+type ConstantLogicalExprRule struct{}
+
+// Apply applies the rule to given file.
+func (r *ConstantLogicalExprRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	onFailure := func(failure lint.Failure) {
+		failures = append(failures, failure)
+	}
+
+	astFile := file.AST
+	w := &lintConstantLogicalExpr{astFile, onFailure}
+	ast.Walk(w, astFile)
+	return failures
+}
+
+// Name returns the rule name.
+func (r *ConstantLogicalExprRule) Name() string {
+	return "constant-logical-expr"
+}
+
+type lintConstantLogicalExpr struct {
+	file      *ast.File
+	onFailure func(lint.Failure)
+}
+
+func (w *lintConstantLogicalExpr) Visit(node ast.Node) ast.Visitor {
+	switch n := node.(type) {
+	case *ast.BinaryExpr:
+		if !w.isOperatorWithLogicalResult(n.Op) {
+			return w
+		}
+
+		if gofmt(n.X) != gofmt(n.Y) { // check if subexpressions are the same
+			return w
+		}
+
+		if n.Op == token.EQL {
+			w.newFailure(n, "expression always evaluates to true")
+			return w
+		}
+
+		if w.isInequalityOperator(n.Op) {
+			w.newFailure(n, "expression always evaluates to false")
+			return w
+		}
+
+		w.newFailure(n, "left and right hand-side sub-expressions are the same")
+	}
+
+	return w
+}
+
+func (w *lintConstantLogicalExpr) isOperatorWithLogicalResult(t token.Token) bool {
+	switch t {
+	case token.LAND, token.LOR, token.EQL, token.LSS, token.GTR, token.NEQ, token.LEQ, token.GEQ:
+		return true
+	}
+
+	return false
+}
+
+func (w *lintConstantLogicalExpr) isInequalityOperator(t token.Token) bool {
+	switch t {
+	case token.LSS, token.GTR, token.NEQ, token.LEQ, token.GEQ:
+		return true
+	}
+
+	return false
+}
+
+func (w lintConstantLogicalExpr) newFailure(node ast.Node, msg string) {
+	w.onFailure(lint.Failure{
+		Confidence: 1,
+		Node:       node,
+		Category:   "logic",
+		Failure:    msg,
+	})
+}

vendor/github.com/mgechev/revive/rule/context-as-argument.go

@@ -0,0 +1,60 @@
+package rule
+
+import (
+	"go/ast"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// ContextAsArgumentRule lints given else constructs.
+type ContextAsArgumentRule struct{}
+
+// Apply applies the rule to given file.
+func (r *ContextAsArgumentRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	fileAst := file.AST
+	walker := lintContextArguments{
+		file:    file,
+		fileAst: fileAst,
+		onFailure: func(failure lint.Failure) {
+			failures = append(failures, failure)
+		},
+	}
+
+	ast.Walk(walker, fileAst)
+
+	return failures
+}
+
+// Name returns the rule name.
+func (r *ContextAsArgumentRule) Name() string {
+	return "context-as-argument"
+}
+
+type lintContextArguments struct {
+	file      *lint.File
+	fileAst   *ast.File
+	onFailure func(lint.Failure)
+}
+
+func (w lintContextArguments) Visit(n ast.Node) ast.Visitor {
+	fn, ok := n.(*ast.FuncDecl)
+	if !ok || len(fn.Type.Params.List) <= 1 {
+		return w
+	}
+	// A context.Context should be the first parameter of a function.
+	// Flag any that show up after the first.
+	for _, arg := range fn.Type.Params.List[1:] {
+		if isPkgDot(arg.Type, "context", "Context") {
+			w.onFailure(lint.Failure{
+				Node:       fn,
+				Category:   "arg-order",
+				Failure:    "context.Context should be the first parameter of a function",
+				Confidence: 0.9,
+			})
+			break // only flag one
+		}
+	}
+	return w
+}

vendor/github.com/mgechev/revive/rule/context-keys-type.go

@@ -0,0 +1,81 @@
+package rule
+
+import (
+	"fmt"
+	"go/ast"
+	"go/types"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// ContextKeysType lints given else constructs.
+type ContextKeysType struct{}
+
+// Apply applies the rule to given file.
+func (r *ContextKeysType) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	fileAst := file.AST
+	walker := lintContextKeyTypes{
+		file:    file,
+		fileAst: fileAst,
+		onFailure: func(failure lint.Failure) {
+			failures = append(failures, failure)
+		},
+	}
+
+	file.Pkg.TypeCheck()
+	ast.Walk(walker, fileAst)
+
+	return failures
+}
+
+// Name returns the rule name.
+func (r *ContextKeysType) Name() string {
+	return "context-keys-type"
+}
+
+type lintContextKeyTypes struct {
+	file      *lint.File
+	fileAst   *ast.File
+	onFailure func(lint.Failure)
+}
+
+func (w lintContextKeyTypes) Visit(n ast.Node) ast.Visitor {
+	switch n := n.(type) {
+	case *ast.CallExpr:
+		checkContextKeyType(w, n)
+	}
+
+	return w
+}
+
+func checkContextKeyType(w lintContextKeyTypes, x *ast.CallExpr) {
+	f := w.file
+	sel, ok := x.Fun.(*ast.SelectorExpr)
+	if !ok {
+		return
+	}
+	pkg, ok := sel.X.(*ast.Ident)
+	if !ok || pkg.Name != "context" {
+		return
+	}
+	if sel.Sel.Name != "WithValue" {
+		return
+	}
+
+	// key is second argument to context.WithValue
+	if len(x.Args) != 3 {
+		return
+	}
+	key := f.Pkg.TypesInfo.Types[x.Args[1]]
+
+	if ktyp, ok := key.Type.(*types.Basic); ok && ktyp.Kind() != types.Invalid {
+		w.onFailure(lint.Failure{
+			Confidence: 1,
+			Node:       x,
+			Category:   "content",
+			Failure:    fmt.Sprintf("should not use basic type %s as key in context.WithValue", key.Type),
+		})
+	}
+}

vendor/github.com/mgechev/revive/rule/cyclomatic.go

@@ -0,0 +1,115 @@
+package rule
+
+import (
+	"fmt"
+	"go/ast"
+	"go/token"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// Based on https://github.com/fzipp/gocyclo
+
+// CyclomaticRule lints given else constructs.
+type CyclomaticRule struct{}
+
+// Apply applies the rule to given file.
+func (r *CyclomaticRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	complexity, ok := arguments[0].(int64) // Alt. non panicking version
+	if !ok {
+		panic("invalid argument for cyclomatic complexity")
+	}
+
+	fileAst := file.AST
+	walker := lintCyclomatic{
+		file:       file,
+		complexity: int(complexity),
+		onFailure: func(failure lint.Failure) {
+			failures = append(failures, failure)
+		},
+	}
+
+	ast.Walk(walker, fileAst)
+
+	return failures
+}
+
+// Name returns the rule name.
+func (r *CyclomaticRule) Name() string {
+	return "cyclomatic"
+}
+
+type lintCyclomatic struct {
+	file       *lint.File
+	complexity int
+	onFailure  func(lint.Failure)
+}
+
+func (w lintCyclomatic) Visit(_ ast.Node) ast.Visitor {
+	f := w.file
+	for _, decl := range f.AST.Decls {
+		if fn, ok := decl.(*ast.FuncDecl); ok {
+			c := complexity(fn)
+			if c > w.complexity {
+				w.onFailure(lint.Failure{
+					Confidence: 1,
+					Category:   "maintenance",
+					Failure:    fmt.Sprintf("function %s has cyclomatic complexity %d", funcName(fn), c),
+					Node:       fn,
+				})
+			}
+		}
+	}
+	return nil
+}
+
+// funcName returns the name representation of a function or method:
+// "(Type).Name" for methods or simply "Name" for functions.
+func funcName(fn *ast.FuncDecl) string {
+	if fn.Recv != nil {
+		if fn.Recv.NumFields() > 0 {
+			typ := fn.Recv.List[0].Type
+			return fmt.Sprintf("(%s).%s", recvString(typ), fn.Name)
+		}
+	}
+	return fn.Name.Name
+}
+
+// recvString returns a string representation of recv of the
+// form "T", "*T", or "BADRECV" (if not a proper receiver type).
+func recvString(recv ast.Expr) string {
+	switch t := recv.(type) {
+	case *ast.Ident:
+		return t.Name
+	case *ast.StarExpr:
+		return "*" + recvString(t.X)
+	}
+	return "BADRECV"
+}
+
+// complexity calculates the cyclomatic complexity of a function.
+func complexity(fn *ast.FuncDecl) int {
+	v := complexityVisitor{}
+	ast.Walk(&v, fn)
+	return v.Complexity
+}
+
+type complexityVisitor struct {
+	// Complexity is the cyclomatic complexity
+	Complexity int
+}
+
+// Visit implements the ast.Visitor interface.
+func (v *complexityVisitor) Visit(n ast.Node) ast.Visitor {
+	switch n := n.(type) {
+	case *ast.FuncDecl, *ast.IfStmt, *ast.ForStmt, *ast.RangeStmt, *ast.CaseClause, *ast.CommClause:
+		v.Complexity++
+	case *ast.BinaryExpr:
+		if n.Op == token.LAND || n.Op == token.LOR {
+			v.Complexity++
+		}
+	}
+	return v
+}

vendor/github.com/mgechev/revive/rule/deep-exit.go

@@ -0,0 +1,94 @@
+package rule
+
+import (
+	"fmt"
+	"go/ast"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// DeepExitRule lints program exit at functions other than main or init.
+type DeepExitRule struct{}
+
+// Apply applies the rule to given file.
+func (r *DeepExitRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+	onFailure := func(failure lint.Failure) {
+		failures = append(failures, failure)
+	}
+
+	var exitFunctions = map[string]map[string]bool{
+		"os":      map[string]bool{"Exit": true},
+		"syscall": map[string]bool{"Exit": true},
+		"log": map[string]bool{
+			"Fatal":   true,
+			"Fatalf":  true,
+			"Fatalln": true,
+			"Panic":   true,
+			"Panicf":  true,
+			"Panicln": true,
+		},
+	}
+
+	w := lintDeepExit{onFailure, exitFunctions, file.IsTest()}
+	ast.Walk(w, file.AST)
+	return failures
+}
+
+// Name returns the rule name.
+func (r *DeepExitRule) Name() string {
+	return "deep-exit"
+}
+
+type lintDeepExit struct {
+	onFailure     func(lint.Failure)
+	exitFunctions map[string]map[string]bool
+	isTestFile    bool
+}
+
+func (w lintDeepExit) Visit(node ast.Node) ast.Visitor {
+	if fd, ok := node.(*ast.FuncDecl); ok {
+		if w.mustIgnore(fd) {
+			return nil // skip analysis of this function
+		}
+
+		return w
+	}
+
+	se, ok := node.(*ast.ExprStmt)
+	if !ok {
+		return w
+	}
+	ce, ok := se.X.(*ast.CallExpr)
+	if !ok {
+		return w
+	}
+
+	fc, ok := ce.Fun.(*ast.SelectorExpr)
+	if !ok {
+		return w
+	}
+	id, ok := fc.X.(*ast.Ident)
+	if !ok {
+		return w
+	}
+
+	fn := fc.Sel.Name
+	pkg := id.Name
+	if w.exitFunctions[pkg] != nil && w.exitFunctions[pkg][fn] { // it's a call to an exit function
+		w.onFailure(lint.Failure{
+			Confidence: 1,
+			Node:       ce,
+			Category:   "bad practice",
+			Failure:    fmt.Sprintf("calls to %s.%s only in main() or init() functions", pkg, fn),
+		})
+	}
+
+	return w
+}
+
+func (w *lintDeepExit) mustIgnore(fd *ast.FuncDecl) bool {
+	fn := fd.Name.Name
+
+	return fn == "init" || fn == "main" || (w.isTestFile && fn == "TestMain")
+}

vendor/github.com/mgechev/revive/rule/dot-imports.go

@@ -0,0 +1,54 @@
+package rule
+
+import (
+	"go/ast"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// DotImportsRule lints given else constructs.
+type DotImportsRule struct{}
+
+// Apply applies the rule to given file.
+func (r *DotImportsRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	fileAst := file.AST
+	walker := lintImports{
+		file:    file,
+		fileAst: fileAst,
+		onFailure: func(failure lint.Failure) {
+			failures = append(failures, failure)
+		},
+	}
+
+	ast.Walk(walker, fileAst)
+
+	return failures
+}
+
+// Name returns the rule name.
+func (r *DotImportsRule) Name() string {
+	return "dot-imports"
+}
+
+type lintImports struct {
+	file      *lint.File
+	fileAst   *ast.File
+	onFailure func(lint.Failure)
+}
+
+func (w lintImports) Visit(_ ast.Node) ast.Visitor {
+	for i, is := range w.fileAst.Imports {
+		_ = i
+		if is.Name != nil && is.Name.Name == "." && !w.file.IsTest() {
+			w.onFailure(lint.Failure{
+				Confidence: 1,
+				Failure:    "should not use dot imports",
+				Node:       is,
+				Category:   "imports",
+			})
+		}
+	}
+	return nil
+}

vendor/github.com/mgechev/revive/rule/duplicated-imports.go

@@ -0,0 +1,39 @@
+package rule
+
+import (
+	"fmt"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// DuplicatedImportsRule lints given else constructs.
+type DuplicatedImportsRule struct{}
+
+// Apply applies the rule to given file.
+func (r *DuplicatedImportsRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	impPaths := map[string]struct{}{}
+	for _, imp := range file.AST.Imports {
+		path := imp.Path.Value
+		_, ok := impPaths[path]
+		if ok {
+			failures = append(failures, lint.Failure{
+				Confidence: 1,
+				Failure:    fmt.Sprintf("Package %s already imported", path),
+				Node:       imp,
+				Category:   "imports",
+			})
+			continue
+		}
+
+		impPaths[path] = struct{}{}
+	}
+
+	return failures
+}
+
+// Name returns the rule name.
+func (r *DuplicatedImportsRule) Name() string {
+	return "duplicated-imports"
+}

vendor/github.com/mgechev/revive/rule/empty-block.go

@@ -0,0 +1,76 @@
+package rule
+
+import (
+	"go/ast"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// EmptyBlockRule lints given else constructs.
+type EmptyBlockRule struct{}
+
+// Apply applies the rule to given file.
+func (r *EmptyBlockRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	onFailure := func(failure lint.Failure) {
+		failures = append(failures, failure)
+	}
+
+	w := lintEmptyBlock{make([]*ast.BlockStmt, 0), onFailure}
+	ast.Walk(w, file.AST)
+	return failures
+}
+
+// Name returns the rule name.
+func (r *EmptyBlockRule) Name() string {
+	return "empty-block"
+}
+
+type lintEmptyBlock struct {
+	ignore    []*ast.BlockStmt
+	onFailure func(lint.Failure)
+}
+
+func (w lintEmptyBlock) Visit(node ast.Node) ast.Visitor {
+	fd, ok := node.(*ast.FuncDecl)
+	if ok {
+		w.ignore = append(w.ignore, fd.Body)
+		return w
+	}
+
+	fl, ok := node.(*ast.FuncLit)
+	if ok {
+		w.ignore = append(w.ignore, fl.Body)
+		return w
+	}
+
+	block, ok := node.(*ast.BlockStmt)
+	if !ok {
+		return w
+	}
+
+	if mustIgnore(block, w.ignore) {
+		return w
+	}
+
+	if len(block.List) == 0 {
+		w.onFailure(lint.Failure{
+			Confidence: 1,
+			Node:       block,
+			Category:   "logic",
+			Failure:    "this block is empty, you can remove it",
+		})
+	}
+
+	return w
+}
+
+func mustIgnore(block *ast.BlockStmt, blackList []*ast.BlockStmt) bool {
+	for _, b := range blackList {
+		if b == block {
+			return true
+		}
+	}
+	return false
+}

vendor/github.com/mgechev/revive/rule/empty-lines.go

@@ -0,0 +1,113 @@
+package rule
+
+import (
+	"go/ast"
+	"go/token"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// EmptyLinesRule lints empty lines in blocks.
+type EmptyLinesRule struct{}
+
+// Apply applies the rule to given file.
+func (r *EmptyLinesRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	onFailure := func(failure lint.Failure) {
+		failures = append(failures, failure)
+	}
+
+	w := lintEmptyLines{file, file.CommentMap(), onFailure}
+	ast.Walk(w, file.AST)
+	return failures
+}
+
+// Name returns the rule name.
+func (r *EmptyLinesRule) Name() string {
+	return "empty-lines"
+}
+
+type lintEmptyLines struct {
+	file      *lint.File
+	cmap      ast.CommentMap
+	onFailure func(lint.Failure)
+}
+
+func (w lintEmptyLines) Visit(node ast.Node) ast.Visitor {
+	block, ok := node.(*ast.BlockStmt)
+	if !ok {
+		return w
+	}
+
+	w.checkStart(block)
+	w.checkEnd(block)
+
+	return w
+}
+
+func (w lintEmptyLines) checkStart(block *ast.BlockStmt) {
+	if len(block.List) == 0 {
+		return
+	}
+
+	start := w.position(block.Lbrace)
+	firstNode := block.List[0]
+
+	if w.commentBetween(start, firstNode) {
+		return
+	}
+
+	first := w.position(firstNode.Pos())
+	if first.Line-start.Line > 1 {
+		w.onFailure(lint.Failure{
+			Confidence: 1,
+			Node:       block,
+			Category:   "style",
+			Failure:    "extra empty line at the start of a block",
+		})
+	}
+}
+
+func (w lintEmptyLines) checkEnd(block *ast.BlockStmt) {
+	if len(block.List) < 1 {
+		return
+	}
+
+	end := w.position(block.Rbrace)
+	lastNode := block.List[len(block.List)-1]
+
+	if w.commentBetween(end, lastNode) {
+		return
+	}
+
+	last := w.position(lastNode.End())
+	if end.Line-last.Line > 1 {
+		w.onFailure(lint.Failure{
+			Confidence: 1,
+			Node:       lastNode,
+			Category:   "style",
+			Failure:    "extra empty line at the end of a block",
+		})
+	}
+}
+
+func (w lintEmptyLines) commentBetween(position token.Position, node ast.Node) bool {
+	comments := w.cmap.Filter(node).Comments()
+	if len(comments) == 0 {
+		return false
+	}
+
+	for _, comment := range comments {
+		start, end := w.position(comment.Pos()), w.position(comment.End())
+		if start.Line-position.Line == 1 || position.Line-end.Line == 1 {
+			return true
+		}
+	}
+
+	return false
+}
+
+func (w lintEmptyLines) position(pos token.Pos) token.Position {
+	return w.file.ToPosition(pos)
+}

vendor/github.com/mgechev/revive/rule/error-naming.go

@@ -0,0 +1,79 @@
+package rule
+
+import (
+	"fmt"
+	"go/ast"
+	"go/token"
+	"strings"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// ErrorNamingRule lints given else constructs.
+type ErrorNamingRule struct{}
+
+// Apply applies the rule to given file.
+func (r *ErrorNamingRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	fileAst := file.AST
+	walker := lintErrors{
+		file:    file,
+		fileAst: fileAst,
+		onFailure: func(failure lint.Failure) {
+			failures = append(failures, failure)
+		},
+	}
+
+	ast.Walk(walker, fileAst)
+
+	return failures
+}
+
+// Name returns the rule name.
+func (r *ErrorNamingRule) Name() string {
+	return "error-naming"
+}
+
+type lintErrors struct {
+	file      *lint.File
+	fileAst   *ast.File
+	onFailure func(lint.Failure)
+}
+
+func (w lintErrors) Visit(_ ast.Node) ast.Visitor {
+	for _, decl := range w.fileAst.Decls {
+		gd, ok := decl.(*ast.GenDecl)
+		if !ok || gd.Tok != token.VAR {
+			continue
+		}
+		for _, spec := range gd.Specs {
+			spec := spec.(*ast.ValueSpec)
+			if len(spec.Names) != 1 || len(spec.Values) != 1 {
+				continue
+			}
+			ce, ok := spec.Values[0].(*ast.CallExpr)
+			if !ok {
+				continue
+			}
+			if !isPkgDot(ce.Fun, "errors", "New") && !isPkgDot(ce.Fun, "fmt", "Errorf") {
+				continue
+			}
+
+			id := spec.Names[0]
+			prefix := "err"
+			if id.IsExported() {
+				prefix = "Err"
+			}
+			if !strings.HasPrefix(id.Name, prefix) {
+				w.onFailure(lint.Failure{
+					Node:       id,
+					Confidence: 0.9,
+					Category:   "naming",
+					Failure:    fmt.Sprintf("error var %s should have name of the form %sFoo", id.Name, prefix),
+				})
+			}
+		}
+	}
+	return nil
+}

vendor/github.com/mgechev/revive/rule/error-return.go

@@ -0,0 +1,67 @@
+package rule
+
+import (
+	"go/ast"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// ErrorReturnRule lints given else constructs.
+type ErrorReturnRule struct{}
+
+// Apply applies the rule to given file.
+func (r *ErrorReturnRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	fileAst := file.AST
+	walker := lintErrorReturn{
+		file:    file,
+		fileAst: fileAst,
+		onFailure: func(failure lint.Failure) {
+			failures = append(failures, failure)
+		},
+	}
+
+	ast.Walk(walker, fileAst)
+
+	return failures
+}
+
+// Name returns the rule name.
+func (r *ErrorReturnRule) Name() string {
+	return "error-return"
+}
+
+type lintErrorReturn struct {
+	file      *lint.File
+	fileAst   *ast.File
+	onFailure func(lint.Failure)
+}
+
+func (w lintErrorReturn) Visit(n ast.Node) ast.Visitor {
+	fn, ok := n.(*ast.FuncDecl)
+	if !ok || fn.Type.Results == nil {
+		return w
+	}
+	ret := fn.Type.Results.List
+	if len(ret) <= 1 {
+		return w
+	}
+	if isIdent(ret[len(ret)-1].Type, "error") {
+		return nil
+	}
+	// An error return parameter should be the last parameter.
+	// Flag any error parameters found before the last.
+	for _, r := range ret[:len(ret)-1] {
+		if isIdent(r.Type, "error") {
+			w.onFailure(lint.Failure{
+				Category:   "arg-order",
+				Confidence: 0.9,
+				Node:       fn,
+				Failure:    "error should be the last type when returning multiple items",
+			})
+			break // only flag one
+		}
+	}
+	return w
+}

vendor/github.com/mgechev/revive/rule/error-strings.go

@@ -0,0 +1,98 @@
+package rule
+
+import (
+	"go/ast"
+	"go/token"
+	"strconv"
+	"unicode"
+	"unicode/utf8"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// ErrorStringsRule lints given else constructs.
+type ErrorStringsRule struct{}
+
+// Apply applies the rule to given file.
+func (r *ErrorStringsRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	fileAst := file.AST
+	walker := lintErrorStrings{
+		file:    file,
+		fileAst: fileAst,
+		onFailure: func(failure lint.Failure) {
+			failures = append(failures, failure)
+		},
+	}
+
+	ast.Walk(walker, fileAst)
+
+	return failures
+}
+
+// Name returns the rule name.
+func (r *ErrorStringsRule) Name() string {
+	return "error-strings"
+}
+
+type lintErrorStrings struct {
+	file      *lint.File
+	fileAst   *ast.File
+	onFailure func(lint.Failure)
+}
+
+func (w lintErrorStrings) Visit(n ast.Node) ast.Visitor {
+	ce, ok := n.(*ast.CallExpr)
+	if !ok {
+		return w
+	}
+	if !isPkgDot(ce.Fun, "errors", "New") && !isPkgDot(ce.Fun, "fmt", "Errorf") {
+		return w
+	}
+	if len(ce.Args) < 1 {
+		return w
+	}
+	str, ok := ce.Args[0].(*ast.BasicLit)
+	if !ok || str.Kind != token.STRING {
+		return w
+	}
+	s, _ := strconv.Unquote(str.Value) // can assume well-formed Go
+	if s == "" {
+		return w
+	}
+	clean, conf := lintErrorString(s)
+	if clean {
+		return w
+	}
+
+	w.onFailure(lint.Failure{
+		Node:       str,
+		Confidence: conf,
+		Category:   "errors",
+		Failure:    "error strings should not be capitalized or end with punctuation or a newline",
+	})
+	return w
+}
+
+func lintErrorString(s string) (isClean bool, conf float64) {
+	const basicConfidence = 0.8
+	const capConfidence = basicConfidence - 0.2
+	first, firstN := utf8.DecodeRuneInString(s)
+	last, _ := utf8.DecodeLastRuneInString(s)
+	if last == '.' || last == ':' || last == '!' || last == '\n' {
+		return false, basicConfidence
+	}
+	if unicode.IsUpper(first) {
+		// People use proper nouns and exported Go identifiers in error strings,
+		// so decrease the confidence of warnings for capitalization.
+		if len(s) <= firstN {
+			return false, capConfidence
+		}
+		// Flag strings starting with something that doesn't look like an initialism.
+		if second, _ := utf8.DecodeRuneInString(s[firstN:]); !unicode.IsUpper(second) {
+			return false, capConfidence
+		}
+	}
+	return true, 0
+}

vendor/github.com/mgechev/revive/rule/errorf.go

@@ -0,0 +1,93 @@
+package rule
+
+import (
+	"fmt"
+	"go/ast"
+	"regexp"
+	"strings"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// ErrorfRule lints given else constructs.
+type ErrorfRule struct{}
+
+// Apply applies the rule to given file.
+func (r *ErrorfRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	fileAst := file.AST
+	walker := lintErrorf{
+		file:    file,
+		fileAst: fileAst,
+		onFailure: func(failure lint.Failure) {
+			failures = append(failures, failure)
+		},
+	}
+
+	file.Pkg.TypeCheck()
+	ast.Walk(walker, fileAst)
+
+	return failures
+}
+
+// Name returns the rule name.
+func (r *ErrorfRule) Name() string {
+	return "errorf"
+}
+
+type lintErrorf struct {
+	file      *lint.File
+	fileAst   *ast.File
+	onFailure func(lint.Failure)
+}
+
+func (w lintErrorf) Visit(n ast.Node) ast.Visitor {
+	ce, ok := n.(*ast.CallExpr)
+	if !ok || len(ce.Args) != 1 {
+		return w
+	}
+	isErrorsNew := isPkgDot(ce.Fun, "errors", "New")
+	var isTestingError bool
+	se, ok := ce.Fun.(*ast.SelectorExpr)
+	if ok && se.Sel.Name == "Error" {
+		if typ := w.file.Pkg.TypeOf(se.X); typ != nil {
+			isTestingError = typ.String() == "*testing.T"
+		}
+	}
+	if !isErrorsNew && !isTestingError {
+		return w
+	}
+	arg := ce.Args[0]
+	ce, ok = arg.(*ast.CallExpr)
+	if !ok || !isPkgDot(ce.Fun, "fmt", "Sprintf") {
+		return w
+	}
+	errorfPrefix := "fmt"
+	if isTestingError {
+		errorfPrefix = w.file.Render(se.X)
+	}
+
+	failure := lint.Failure{
+		Category:   "errors",
+		Node:       n,
+		Confidence: 1,
+		Failure:    fmt.Sprintf("should replace %s(fmt.Sprintf(...)) with %s.Errorf(...)", w.file.Render(se), errorfPrefix),
+	}
+
+	m := srcLineWithMatch(w.file, ce, `^(.*)`+w.file.Render(se)+`\(fmt\.Sprintf\((.*)\)\)(.*)$`)
+	if m != nil {
+		failure.ReplacementLine = m[1] + errorfPrefix + ".Errorf(" + m[2] + ")" + m[3]
+	}
+
+	w.onFailure(failure)
+
+	return w
+}
+
+func srcLineWithMatch(file *lint.File, node ast.Node, pattern string) (m []string) {
+	line := srcLine(file.Content(), file.ToPosition(node.Pos()))
+	line = strings.TrimSuffix(line, "\n")
+	rx := regexp.MustCompile(pattern)
+	return rx.FindStringSubmatch(line)
+}

vendor/github.com/mgechev/revive/rule/exported.go

@@ -0,0 +1,272 @@
+package rule
+
+import (
+	"fmt"
+	"go/ast"
+	"go/token"
+	"strings"
+	"unicode"
+	"unicode/utf8"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// ExportedRule lints given else constructs.
+type ExportedRule struct{}
+
+// Apply applies the rule to given file.
+func (r *ExportedRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	if isTest(file) {
+		return failures
+	}
+
+	fileAst := file.AST
+	walker := lintExported{
+		file:    file,
+		fileAst: fileAst,
+		onFailure: func(failure lint.Failure) {
+			failures = append(failures, failure)
+		},
+		genDeclMissingComments: make(map[*ast.GenDecl]bool),
+	}
+
+	ast.Walk(&walker, fileAst)
+
+	return failures
+}
+
+// Name returns the rule name.
+func (r *ExportedRule) Name() string {
+	return "exported"
+}
+
+type lintExported struct {
+	file                   *lint.File
+	fileAst                *ast.File
+	lastGen                *ast.GenDecl
+	genDeclMissingComments map[*ast.GenDecl]bool
+	onFailure              func(lint.Failure)
+}
+
+func (w *lintExported) lintFuncDoc(fn *ast.FuncDecl) {
+	if !ast.IsExported(fn.Name.Name) {
+		// func is unexported
+		return
+	}
+	kind := "function"
+	name := fn.Name.Name
+	if fn.Recv != nil && len(fn.Recv.List) > 0 {
+		// method
+		kind = "method"
+		recv := receiverType(fn)
+		if !ast.IsExported(recv) {
+			// receiver is unexported
+			return
+		}
+		if commonMethods[name] {
+			return
+		}
+		switch name {
+		case "Len", "Less", "Swap":
+			if w.file.Pkg.Sortable[recv] {
+				return
+			}
+		}
+		name = recv + "." + name
+	}
+	if fn.Doc == nil {
+		w.onFailure(lint.Failure{
+			Node:       fn,
+			Confidence: 1,
+			Category:   "comments",
+			Failure:    fmt.Sprintf("exported %s %s should have comment or be unexported", kind, name),
+		})
+		return
+	}
+	s := normalizeText(fn.Doc.Text())
+	prefix := fn.Name.Name + " "
+	if !strings.HasPrefix(s, prefix) {
+		w.onFailure(lint.Failure{
+			Node:       fn.Doc,
+			Confidence: 0.8,
+			Category:   "comments",
+			Failure:    fmt.Sprintf(`comment on exported %s %s should be of the form "%s..."`, kind, name, prefix),
+		})
+	}
+}
+
+func (w *lintExported) checkStutter(id *ast.Ident, thing string) {
+	pkg, name := w.fileAst.Name.Name, id.Name
+	if !ast.IsExported(name) {
+		// unexported name
+		return
+	}
+	// A name stutters if the package name is a strict prefix
+	// and the next character of the name starts a new word.
+	if len(name) <= len(pkg) {
+		// name is too short to stutter.
+		// This permits the name to be the same as the package name.
+		return
+	}
+	if !strings.EqualFold(pkg, name[:len(pkg)]) {
+		return
+	}
+	// We can assume the name is well-formed UTF-8.
+	// If the next rune after the package name is uppercase or an underscore
+	// the it's starting a new word and thus this name stutters.
+	rem := name[len(pkg):]
+	if next, _ := utf8.DecodeRuneInString(rem); next == '_' || unicode.IsUpper(next) {
+		w.onFailure(lint.Failure{
+			Node:       id,
+			Confidence: 0.8,
+			Category:   "naming",
+			Failure:    fmt.Sprintf("%s name will be used as %s.%s by other packages, and that stutters; consider calling this %s", thing, pkg, name, rem),
+		})
+	}
+}
+
+func (w *lintExported) lintTypeDoc(t *ast.TypeSpec, doc *ast.CommentGroup) {
+	if !ast.IsExported(t.Name.Name) {
+		return
+	}
+	if doc == nil {
+		w.onFailure(lint.Failure{
+			Node:       t,
+			Confidence: 1,
+			Category:   "comments",
+			Failure:    fmt.Sprintf("exported type %v should have comment or be unexported", t.Name),
+		})
+		return
+	}
+
+	s := normalizeText(doc.Text())
+	articles := [...]string{"A", "An", "The", "This"}
+	for _, a := range articles {
+		if t.Name.Name == a {
+			continue
+		}
+		if strings.HasPrefix(s, a+" ") {
+			s = s[len(a)+1:]
+			break
+		}
+	}
+	if !strings.HasPrefix(s, t.Name.Name+" ") {
+		w.onFailure(lint.Failure{
+			Node:       doc,
+			Confidence: 1,
+			Category:   "comments",
+			Failure:    fmt.Sprintf(`comment on exported type %v should be of the form "%v ..." (with optional leading article)`, t.Name, t.Name),
+		})
+	}
+}
+
+func (w *lintExported) lintValueSpecDoc(vs *ast.ValueSpec, gd *ast.GenDecl, genDeclMissingComments map[*ast.GenDecl]bool) {
+	kind := "var"
+	if gd.Tok == token.CONST {
+		kind = "const"
+	}
+
+	if len(vs.Names) > 1 {
+		// Check that none are exported except for the first.
+		for _, n := range vs.Names[1:] {
+			if ast.IsExported(n.Name) {
+				w.onFailure(lint.Failure{
+					Category:   "comments",
+					Confidence: 1,
+					Failure:    fmt.Sprintf("exported %s %s should have its own declaration", kind, n.Name),
+					Node:       vs,
+				})
+				return
+			}
+		}
+	}
+
+	// Only one name.
+	name := vs.Names[0].Name
+	if !ast.IsExported(name) {
+		return
+	}
+
+	if vs.Doc == nil && gd.Doc == nil {
+		if genDeclMissingComments[gd] {
+			return
+		}
+		block := ""
+		if kind == "const" && gd.Lparen.IsValid() {
+			block = " (or a comment on this block)"
+		}
+		w.onFailure(lint.Failure{
+			Confidence: 1,
+			Node:       vs,
+			Category:   "comments",
+			Failure:    fmt.Sprintf("exported %s %s should have comment%s or be unexported", kind, name, block),
+		})
+		genDeclMissingComments[gd] = true
+		return
+	}
+	// If this GenDecl has parens and a comment, we don't check its comment form.
+	if gd.Lparen.IsValid() && gd.Doc != nil {
+		return
+	}
+	// The relevant text to check will be on either vs.Doc or gd.Doc.
+	// Use vs.Doc preferentially.
+	doc := vs.Doc
+	if doc == nil {
+		doc = gd.Doc
+	}
+	prefix := name + " "
+	s := normalizeText(doc.Text())
+	if !strings.HasPrefix(s, prefix) {
+		w.onFailure(lint.Failure{
+			Confidence: 1,
+			Node:       doc,
+			Category:   "comments",
+			Failure:    fmt.Sprintf(`comment on exported %s %s should be of the form "%s..."`, kind, name, prefix),
+		})
+	}
+}
+
+// normalizeText is a helper function that normalizes comment strings by:
+// * removing one leading space
+//
+// This function is needed because ast.CommentGroup.Text() does not handle //-style and /*-style comments uniformly
+func normalizeText(t string) string {
+	return strings.TrimPrefix(t, " ")
+}
+
+func (w *lintExported) Visit(n ast.Node) ast.Visitor {
+	switch v := n.(type) {
+	case *ast.GenDecl:
+		if v.Tok == token.IMPORT {
+			return nil
+		}
+		// token.CONST, token.TYPE or token.VAR
+		w.lastGen = v
+		return w
+	case *ast.FuncDecl:
+		w.lintFuncDoc(v)
+		if v.Recv == nil {
+			// Only check for stutter on functions, not methods.
+			// Method names are not used package-qualified.
+			w.checkStutter(v.Name, "func")
+		}
+		// Don't proceed inside funcs.
+		return nil
+	case *ast.TypeSpec:
+		// inside a GenDecl, which usually has the doc
+		doc := v.Doc
+		if doc == nil {
+			doc = w.lastGen.Doc
+		}
+		w.lintTypeDoc(v, doc)
+		w.checkStutter(v.Name, "type")
+		// Don't proceed inside types.
+		return nil
+	case *ast.ValueSpec:
+		w.lintValueSpecDoc(v, w.lastGen, w.genDeclMissingComments)
+		return nil
+	}
+	return w
+}

vendor/github.com/mgechev/revive/rule/file-header.go

@@ -0,0 +1,69 @@
+package rule
+
+import (
+	"regexp"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// FileHeaderRule lints given else constructs.
+type FileHeaderRule struct{}
+
+var (
+	multiRegexp  = regexp.MustCompile("^/\\*")
+	singleRegexp = regexp.MustCompile("^//")
+)
+
+// Apply applies the rule to given file.
+func (r *FileHeaderRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
+	if len(arguments) != 1 {
+		panic(`invalid configuration for "file-header" rule`)
+	}
+
+	header, ok := arguments[0].(string)
+	if !ok {
+		panic(`invalid argument for "file-header" rule: first argument should be a string`)
+	}
+
+	failure := []lint.Failure{
+		{
+			Node:       file.AST,
+			Confidence: 1,
+			Failure:    "the file doesn't have an appropriate header",
+		},
+	}
+
+	if len(file.AST.Comments) == 0 {
+		return failure
+	}
+
+	g := file.AST.Comments[0]
+	if g == nil {
+		return failure
+	}
+	comment := ""
+	for _, c := range g.List {
+		text := c.Text
+		if multiRegexp.Match([]byte(text)) {
+			text = text[2 : len(text)-2]
+		} else if singleRegexp.Match([]byte(text)) {
+			text = text[2:]
+		}
+		comment += text
+	}
+
+	regex, err := regexp.Compile(header)
+	if err != nil {
+		panic(err.Error())
+	}
+
+	if !regex.Match([]byte(comment)) {
+		return failure
+	}
+	return nil
+}
+
+// Name returns the rule name.
+func (r *FileHeaderRule) Name() string {
+	return "file-header"
+}

vendor/github.com/mgechev/revive/rule/flag-param.go

@@ -0,0 +1,104 @@
+package rule
+
+import (
+	"fmt"
+	"github.com/mgechev/revive/lint"
+	"go/ast"
+)
+
+// FlagParamRule lints given else constructs.
+type FlagParamRule struct{}
+
+// Apply applies the rule to given file.
+func (r *FlagParamRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	onFailure := func(failure lint.Failure) {
+		failures = append(failures, failure)
+	}
+
+	w := lintFlagParamRule{onFailure: onFailure}
+	ast.Walk(w, file.AST)
+	return failures
+}
+
+// Name returns the rule name.
+func (r *FlagParamRule) Name() string {
+	return "flag-parameter"
+}
+
+type lintFlagParamRule struct {
+	onFailure func(lint.Failure)
+}
+
+func (w lintFlagParamRule) Visit(node ast.Node) ast.Visitor {
+	fd, ok := node.(*ast.FuncDecl)
+	if !ok {
+		return w
+	}
+
+	if fd.Body == nil {
+		return nil // skip whole function declaration
+	}
+
+	for _, p := range fd.Type.Params.List {
+		t := p.Type
+
+		id, ok := t.(*ast.Ident)
+		if !ok {
+			continue
+		}
+
+		if id.Name != "bool" {
+			continue
+		}
+
+		cv := conditionVisitor{p.Names, fd, w}
+		ast.Walk(cv, fd.Body)
+	}
+
+	return w
+}
+
+type conditionVisitor struct {
+	ids    []*ast.Ident
+	fd     *ast.FuncDecl
+	linter lintFlagParamRule
+}
+
+func (w conditionVisitor) Visit(node ast.Node) ast.Visitor {
+	ifStmt, ok := node.(*ast.IfStmt)
+	if !ok {
+		return w
+	}
+
+	fselect := func(n ast.Node) bool {
+		ident, ok := n.(*ast.Ident)
+		if !ok {
+			return false
+		}
+
+		for _, id := range w.ids {
+			if ident.Name == id.Name {
+				return true
+			}
+		}
+
+		return false
+	}
+
+	uses := pick(ifStmt.Cond, fselect, nil)
+
+	if len(uses) < 1 {
+		return w
+	}
+
+	w.linter.onFailure(lint.Failure{
+		Confidence: 1,
+		Node:       w.fd.Type.Params,
+		Category:   "bad practice",
+		Failure:    fmt.Sprintf("parameter '%s' seems to be a control flag, avoid control coupling", uses[0]),
+	})
+
+	return nil
+}

vendor/github.com/mgechev/revive/rule/function-result-limit.go

@@ -0,0 +1,68 @@
+package rule
+
+import (
+	"fmt"
+	"go/ast"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// FunctionResultsLimitRule lints given else constructs.
+type FunctionResultsLimitRule struct{}
+
+// Apply applies the rule to given file.
+func (r *FunctionResultsLimitRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
+	if len(arguments) != 1 {
+		panic(`invalid configuration for "function-result-limit"`)
+	}
+
+	max, ok := arguments[0].(int64) // Alt. non panicking version
+	if !ok {
+		panic(fmt.Sprintf(`invalid value passed as return results number to the "function-result-limit" rule; need int64 but got %T`, arguments[0]))
+	}
+	if max < 0 {
+		panic(`the value passed as return results number to the "function-result-limit" rule cannot be negative`)
+	}
+
+	var failures []lint.Failure
+
+	walker := lintFunctionResultsNum{
+		max: int(max),
+		onFailure: func(failure lint.Failure) {
+			failures = append(failures, failure)
+		},
+	}
+
+	ast.Walk(walker, file.AST)
+
+	return failures
+}
+
+// Name returns the rule name.
+func (r *FunctionResultsLimitRule) Name() string {
+	return "function-result-limit"
+}
+
+type lintFunctionResultsNum struct {
+	max       int
+	onFailure func(lint.Failure)
+}
+
+func (w lintFunctionResultsNum) Visit(n ast.Node) ast.Visitor {
+	node, ok := n.(*ast.FuncDecl)
+	if ok {
+		num := 0
+		if node.Type.Results != nil {
+			num = node.Type.Results.NumFields()
+		}
+		if num > w.max {
+			w.onFailure(lint.Failure{
+				Confidence: 1,
+				Failure:    fmt.Sprintf("maximum number of return results per function exceeded; max %d but got %d", w.max, num),
+				Node:       node.Type,
+			})
+			return w
+		}
+	}
+	return w
+}

vendor/github.com/mgechev/revive/rule/get-return.go

@@ -0,0 +1,70 @@
+package rule
+
+import (
+	"fmt"
+	"go/ast"
+	"strings"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// GetReturnRule lints given else constructs.
+type GetReturnRule struct{}
+
+// Apply applies the rule to given file.
+func (r *GetReturnRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	onFailure := func(failure lint.Failure) {
+		failures = append(failures, failure)
+	}
+
+	w := lintReturnRule{onFailure}
+	ast.Walk(w, file.AST)
+	return failures
+}
+
+// Name returns the rule name.
+func (r *GetReturnRule) Name() string {
+	return "get-return"
+}
+
+type lintReturnRule struct {
+	onFailure func(lint.Failure)
+}
+
+func isGetter(name string) bool {
+	if strings.HasPrefix(strings.ToUpper(name), "GET") {
+		if len(name) > 3 {
+			c := name[3]
+			return !(c >= 'a' && c <= 'z')
+		}
+	}
+
+	return false
+}
+
+func hasResults(rs *ast.FieldList) bool {
+	return rs != nil && len(rs.List) > 0
+}
+
+func (w lintReturnRule) Visit(node ast.Node) ast.Visitor {
+	fd, ok := node.(*ast.FuncDecl)
+	if !ok {
+		return w
+	}
+
+	if !isGetter(fd.Name.Name) {
+		return w
+	}
+	if !hasResults(fd.Type.Results) {
+		w.onFailure(lint.Failure{
+			Confidence: 0.8,
+			Node:       fd,
+			Category:   "logic",
+			Failure:    fmt.Sprintf("function '%s' seems to be a getter but it does not return any result", fd.Name.Name),
+		})
+	}
+
+	return w
+}

vendor/github.com/mgechev/revive/rule/if-return.go

@@ -0,0 +1,115 @@
+package rule
+
+import (
+	"go/ast"
+	"go/token"
+	"strings"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// IfReturnRule lints given else constructs.
+type IfReturnRule struct{}
+
+// Apply applies the rule to given file.
+func (r *IfReturnRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	onFailure := func(failure lint.Failure) {
+		failures = append(failures, failure)
+	}
+
+	astFile := file.AST
+	w := &lintElseError{astFile, onFailure}
+	ast.Walk(w, astFile)
+	return failures
+}
+
+// Name returns the rule name.
+func (r *IfReturnRule) Name() string {
+	return "if-return"
+}
+
+type lintElseError struct {
+	file      *ast.File
+	onFailure func(lint.Failure)
+}
+
+func (w *lintElseError) Visit(node ast.Node) ast.Visitor {
+	switch v := node.(type) {
+	case *ast.BlockStmt:
+		for i := 0; i < len(v.List)-1; i++ {
+			// if var := whatever; var != nil { return var }
+			s, ok := v.List[i].(*ast.IfStmt)
+			if !ok || s.Body == nil || len(s.Body.List) != 1 || s.Else != nil {
+				continue
+			}
+			assign, ok := s.Init.(*ast.AssignStmt)
+			if !ok || len(assign.Lhs) != 1 || !(assign.Tok == token.DEFINE || assign.Tok == token.ASSIGN) {
+				continue
+			}
+			id, ok := assign.Lhs[0].(*ast.Ident)
+			if !ok {
+				continue
+			}
+			expr, ok := s.Cond.(*ast.BinaryExpr)
+			if !ok || expr.Op != token.NEQ {
+				continue
+			}
+			if lhs, ok := expr.X.(*ast.Ident); !ok || lhs.Name != id.Name {
+				continue
+			}
+			if rhs, ok := expr.Y.(*ast.Ident); !ok || rhs.Name != "nil" {
+				continue
+			}
+			r, ok := s.Body.List[0].(*ast.ReturnStmt)
+			if !ok || len(r.Results) != 1 {
+				continue
+			}
+			if r, ok := r.Results[0].(*ast.Ident); !ok || r.Name != id.Name {
+				continue
+			}
+
+			// return nil
+			r, ok = v.List[i+1].(*ast.ReturnStmt)
+			if !ok || len(r.Results) != 1 {
+				continue
+			}
+			if r, ok := r.Results[0].(*ast.Ident); !ok || r.Name != "nil" {
+				continue
+			}
+
+			// check if there are any comments explaining the construct, don't emit an error if there are some.
+			if containsComments(s.Pos(), r.Pos(), w.file) {
+				continue
+			}
+
+			w.onFailure(lint.Failure{
+				Confidence: .9,
+				Node:       v.List[i],
+				Failure:    "redundant if ...; err != nil check, just return error instead.",
+			})
+		}
+	}
+	return w
+}
+
+func containsComments(start, end token.Pos, f *ast.File) bool {
+	for _, cgroup := range f.Comments {
+		comments := cgroup.List
+		if comments[0].Slash >= end {
+			// All comments starting with this group are after end pos.
+			return false
+		}
+		if comments[len(comments)-1].Slash < start {
+			// Comments group ends before start pos.
+			continue
+		}
+		for _, c := range comments {
+			if start <= c.Slash && c.Slash < end && !strings.HasPrefix(c.Text, "// MATCH ") {
+				return true
+			}
+		}
+	}
+	return false
+}

vendor/github.com/mgechev/revive/rule/import-shadowing.go

@@ -0,0 +1,102 @@
+package rule
+
+import (
+	"fmt"
+	"go/ast"
+	"go/token"
+	"strings"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// ImportShadowingRule lints given else constructs.
+type ImportShadowingRule struct{}
+
+// Apply applies the rule to given file.
+func (r *ImportShadowingRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	importNames := map[string]struct{}{}
+	for _, imp := range file.AST.Imports {
+		importNames[getName(imp)] = struct{}{}
+	}
+
+	fileAst := file.AST
+	walker := importShadowing{
+		importNames: importNames,
+		onFailure: func(failure lint.Failure) {
+			failures = append(failures, failure)
+		},
+		alreadySeen: map[*ast.Object]struct{}{},
+	}
+
+	ast.Walk(walker, fileAst)
+
+	return failures
+}
+
+// Name returns the rule name.
+func (r *ImportShadowingRule) Name() string {
+	return "import-shadowing"
+}
+
+func getName(imp *ast.ImportSpec) string {
+	const pathSep = "/"
+	const strDelim = `"`
+	if imp.Name != nil {
+		return imp.Name.Name
+	}
+
+	path := imp.Path.Value
+	i := strings.LastIndex(path, pathSep)
+	if i == -1 {
+		return strings.Trim(path, strDelim)
+	}
+
+	return strings.Trim(path[i+1:], strDelim)
+}
+
+type importShadowing struct {
+	importNames map[string]struct{}
+	onFailure   func(lint.Failure)
+	alreadySeen map[*ast.Object]struct{}
+}
+
+// Visit visits AST nodes and checks if id nodes (ast.Ident) shadow an import name
+func (w importShadowing) Visit(n ast.Node) ast.Visitor {
+	switch n := n.(type) {
+	case *ast.AssignStmt:
+		if n.Tok == token.DEFINE {
+			return w // analyze variable declarations of the form id := expr
+		}
+
+		return nil // skip assigns of the form id = expr (not an id declaration)
+	case *ast.CallExpr, // skip call expressions (not an id declaration)
+		*ast.ImportSpec,   // skip import section subtree because we already have the list of imports
+		*ast.KeyValueExpr, // skip analysis of key-val expressions ({key:value}): ids of such expressions, even the same of an import name, do not shadow the import name
+		*ast.ReturnStmt,   // skip skipping analysis of returns, ids in expression were already analyzed
+		*ast.SelectorExpr, // skip analysis of selector expressions (anId.otherId): because if anId shadows an import name, it was already detected, and otherId does not shadows the import name
+		*ast.StructType:   // skip analysis of struct type because struct fields can not shadow an import name
+		return nil
+	case *ast.Ident:
+		id := n.Name
+		if id == "_" {
+			return w // skip _ id
+		}
+
+		_, isImportName := w.importNames[id]
+		_, alreadySeen := w.alreadySeen[n.Obj]
+		if isImportName && !alreadySeen {
+			w.onFailure(lint.Failure{
+				Confidence: 1,
+				Node:       n,
+				Category:   "namming",
+				Failure:    fmt.Sprintf("The name '%s' shadows an import name", id),
+			})
+
+			w.alreadySeen[n.Obj] = struct{}{}
+		}
+	}
+
+	return w
+}

vendor/github.com/mgechev/revive/rule/imports-blacklist.go

@@ -0,0 +1,52 @@
+package rule
+
+import (
+	"fmt"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// ImportsBlacklistRule lints given else constructs.
+type ImportsBlacklistRule struct{}
+
+// Apply applies the rule to given file.
+func (r *ImportsBlacklistRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	if file.IsTest() {
+		return failures // skip, test file
+	}
+
+	blacklist := make(map[string]bool, len(arguments))
+
+	for _, arg := range arguments {
+		argStr, ok := arg.(string)
+		if !ok {
+			panic(fmt.Sprintf("Invalid argument to the imports-blacklist rule. Expecting a string, got %T", arg))
+		}
+		// we add quotes if not present, because when parsed, the value of the AST node, will be quoted
+		if len(argStr) > 2 && argStr[0] != '"' && argStr[len(argStr)-1] != '"' {
+			argStr = fmt.Sprintf(`"%s"`, argStr)
+		}
+		blacklist[argStr] = true
+	}
+
+	for _, is := range file.AST.Imports {
+		path := is.Path
+		if path != nil && blacklist[path.Value] {
+			failures = append(failures, lint.Failure{
+				Confidence: 1,
+				Failure:    "should not use the following blacklisted import: " + path.Value,
+				Node:       is,
+				Category:   "imports",
+			})
+		}
+	}
+
+	return failures
+}
+
+// Name returns the rule name.
+func (r *ImportsBlacklistRule) Name() string {
+	return "imports-blacklist"
+}

vendor/github.com/mgechev/revive/rule/increment-decrement.go

@@ -0,0 +1,74 @@
+package rule
+
+import (
+	"fmt"
+	"go/ast"
+	"go/token"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// IncrementDecrementRule lints given else constructs.
+type IncrementDecrementRule struct{}
+
+// Apply applies the rule to given file.
+func (r *IncrementDecrementRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	fileAst := file.AST
+	walker := lintIncrementDecrement{
+		file: file,
+		onFailure: func(failure lint.Failure) {
+			failures = append(failures, failure)
+		},
+	}
+
+	ast.Walk(walker, fileAst)
+
+	return failures
+}
+
+// Name returns the rule name.
+func (r *IncrementDecrementRule) Name() string {
+	return "increment-decrement"
+}
+
+type lintIncrementDecrement struct {
+	file      *lint.File
+	fileAst   *ast.File
+	onFailure func(lint.Failure)
+}
+
+func (w lintIncrementDecrement) Visit(n ast.Node) ast.Visitor {
+	as, ok := n.(*ast.AssignStmt)
+	if !ok {
+		return w
+	}
+	if len(as.Lhs) != 1 {
+		return w
+	}
+	if !isOne(as.Rhs[0]) {
+		return w
+	}
+	var suffix string
+	switch as.Tok {
+	case token.ADD_ASSIGN:
+		suffix = "++"
+	case token.SUB_ASSIGN:
+		suffix = "--"
+	default:
+		return w
+	}
+	w.onFailure(lint.Failure{
+		Confidence: 0.8,
+		Node:       as,
+		Category:   "unary-op",
+		Failure:    fmt.Sprintf("should replace %s with %s%s", w.file.Render(as), w.file.Render(as.Lhs[0]), suffix),
+	})
+	return w
+}
+
+func isOne(expr ast.Expr) bool {
+	lit, ok := expr.(*ast.BasicLit)
+	return ok && lit.Kind == token.INT && lit.Value == "1"
+}

vendor/github.com/mgechev/revive/rule/indent-error-flow.go

@@ -0,0 +1,78 @@
+package rule
+
+import (
+	"go/ast"
+	"go/token"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// IndentErrorFlowRule lints given else constructs.
+type IndentErrorFlowRule struct{}
+
+// Apply applies the rule to given file.
+func (r *IndentErrorFlowRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	onFailure := func(failure lint.Failure) {
+		failures = append(failures, failure)
+	}
+
+	w := lintElse{make(map[*ast.IfStmt]bool), onFailure}
+	ast.Walk(w, file.AST)
+	return failures
+}
+
+// Name returns the rule name.
+func (r *IndentErrorFlowRule) Name() string {
+	return "indent-error-flow"
+}
+
+type lintElse struct {
+	ignore    map[*ast.IfStmt]bool
+	onFailure func(lint.Failure)
+}
+
+func (w lintElse) Visit(node ast.Node) ast.Visitor {
+	ifStmt, ok := node.(*ast.IfStmt)
+	if !ok || ifStmt.Else == nil {
+		return w
+	}
+	if w.ignore[ifStmt] {
+		if elseif, ok := ifStmt.Else.(*ast.IfStmt); ok {
+			w.ignore[elseif] = true
+		}
+		return w
+	}
+	if elseif, ok := ifStmt.Else.(*ast.IfStmt); ok {
+		w.ignore[elseif] = true
+		return w
+	}
+	if _, ok := ifStmt.Else.(*ast.BlockStmt); !ok {
+		// only care about elses without conditions
+		return w
+	}
+	if len(ifStmt.Body.List) == 0 {
+		return w
+	}
+	shortDecl := false // does the if statement have a ":=" initialization statement?
+	if ifStmt.Init != nil {
+		if as, ok := ifStmt.Init.(*ast.AssignStmt); ok && as.Tok == token.DEFINE {
+			shortDecl = true
+		}
+	}
+	lastStmt := ifStmt.Body.List[len(ifStmt.Body.List)-1]
+	if _, ok := lastStmt.(*ast.ReturnStmt); ok {
+		extra := ""
+		if shortDecl {
+			extra = " (move short variable declaration to its own line if necessary)"
+		}
+		w.onFailure(lint.Failure{
+			Confidence: 1,
+			Node:       ifStmt.Else,
+			Category:   "indent",
+			Failure:    "if block ends with a return statement, so drop this else and outdent its block" + extra,
+		})
+	}
+	return w
+}

vendor/github.com/mgechev/revive/rule/line-length-limit.go

@@ -0,0 +1,84 @@
+package rule
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"go/token"
+	"strings"
+	"unicode/utf8"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// LineLengthLimitRule lints given else constructs.
+type LineLengthLimitRule struct{}
+
+// Apply applies the rule to given file.
+func (r *LineLengthLimitRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
+	if len(arguments) != 1 {
+		panic(`invalid configuration for "line-length-limit"`)
+	}
+
+	max, ok := arguments[0].(int64) // Alt. non panicking version
+	if !ok || max < 0 {
+		panic(`invalid value passed as argument number to the "line-length-limit" rule`)
+	}
+
+	var failures []lint.Failure
+	checker := lintLineLengthNum{
+		max:  int(max),
+		file: file,
+		onFailure: func(failure lint.Failure) {
+			failures = append(failures, failure)
+		},
+	}
+
+	checker.check()
+
+	return failures
+}
+
+// Name returns the rule name.
+func (r *LineLengthLimitRule) Name() string {
+	return "line-length-limit"
+}
+
+type lintLineLengthNum struct {
+	max       int
+	file      *lint.File
+	onFailure func(lint.Failure)
+}
+
+func (r lintLineLengthNum) check() {
+	f := bytes.NewReader(r.file.Content())
+	spaces := strings.Repeat(" ", 4) // tab width = 4
+	l := 1
+	s := bufio.NewScanner(f)
+	for s.Scan() {
+		t := s.Text()
+		t = strings.Replace(t, "\t", spaces, -1)
+		c := utf8.RuneCountInString(t)
+		if c > r.max {
+			r.onFailure(lint.Failure{
+				Category: "code-style",
+				Position: lint.FailurePosition{
+					// Offset not set; it is non-trivial, and doesn't appear to be needed.
+					Start: token.Position{
+						Filename: r.file.Name,
+						Line:     l,
+						Column:   0,
+					},
+					End: token.Position{
+						Filename: r.file.Name,
+						Line:     l,
+						Column:   c,
+					},
+				},
+				Confidence: 1,
+				Failure:    fmt.Sprintf("line is %d characters, out of limit %d", c, r.max),
+			})
+		}
+		l++
+	}
+}

vendor/github.com/mgechev/revive/rule/max-public-structs.go

@@ -0,0 +1,67 @@
+package rule
+
+import (
+	"go/ast"
+
+	"strings"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// MaxPublicStructsRule lints given else constructs.
+type MaxPublicStructsRule struct{}
+
+// Apply applies the rule to given file.
+func (r *MaxPublicStructsRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	fileAst := file.AST
+	walker := &lintMaxPublicStructs{
+		fileAst: fileAst,
+		onFailure: func(failure lint.Failure) {
+			failures = append(failures, failure)
+		},
+	}
+
+	ast.Walk(walker, fileAst)
+
+	max, ok := arguments[0].(int64) // Alt. non panicking version
+	if !ok {
+		panic(`invalid value passed as argument number to the "max-public-structs" rule`)
+	}
+
+	if walker.current > max {
+		walker.onFailure(lint.Failure{
+			Failure:    "you have exceeded the maximum number of public struct declarations",
+			Confidence: 1,
+			Node:       fileAst,
+			Category:   "style",
+		})
+	}
+
+	return failures
+}
+
+// Name returns the rule name.
+func (r *MaxPublicStructsRule) Name() string {
+	return "max-public-structs"
+}
+
+type lintMaxPublicStructs struct {
+	current   int64
+	fileAst   *ast.File
+	onFailure func(lint.Failure)
+}
+
+func (w *lintMaxPublicStructs) Visit(n ast.Node) ast.Visitor {
+	switch v := n.(type) {
+	case *ast.TypeSpec:
+		name := v.Name.Name
+		first := string(name[0])
+		if strings.ToUpper(first) == first {
+			w.current++
+		}
+		break
+	}
+	return w
+}

vendor/github.com/mgechev/revive/rule/modifies-param.go

@@ -0,0 +1,80 @@
+package rule
+
+import (
+	"fmt"
+	"go/ast"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// ModifiesParamRule lints given else constructs.
+type ModifiesParamRule struct{}
+
+// Apply applies the rule to given file.
+func (r *ModifiesParamRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	onFailure := func(failure lint.Failure) {
+		failures = append(failures, failure)
+	}
+
+	w := lintModifiesParamRule{onFailure: onFailure}
+	ast.Walk(w, file.AST)
+	return failures
+}
+
+// Name returns the rule name.
+func (r *ModifiesParamRule) Name() string {
+	return "modifies-parameter"
+}
+
+type lintModifiesParamRule struct {
+	params    map[string]bool
+	onFailure func(lint.Failure)
+}
+
+func retrieveParamNames(pl []*ast.Field) map[string]bool {
+	result := make(map[string]bool, len(pl))
+	for _, p := range pl {
+		for _, n := range p.Names {
+			if n.Name == "_" {
+				continue
+			}
+
+			result[n.Name] = true
+		}
+	}
+	return result
+}
+
+func (w lintModifiesParamRule) Visit(node ast.Node) ast.Visitor {
+	switch v := node.(type) {
+	case *ast.FuncDecl:
+		w.params = retrieveParamNames(v.Type.Params.List)
+	case *ast.IncDecStmt:
+		if id, ok := v.X.(*ast.Ident); ok {
+			checkParam(id, &w)
+		}
+	case *ast.AssignStmt:
+		lhs := v.Lhs
+		for _, e := range lhs {
+			id, ok := e.(*ast.Ident)
+			if ok {
+				checkParam(id, &w)
+			}
+		}
+	}
+
+	return w
+}
+
+func checkParam(id *ast.Ident, w *lintModifiesParamRule) {
+	if w.params[id.Name] {
+		w.onFailure(lint.Failure{
+			Confidence: 0.5, // confidence is low because of shadow variables
+			Node:       id,
+			Category:   "bad practice",
+			Failure:    fmt.Sprintf("parameter '%s' seems to be modified", id),
+		})
+	}
+}

vendor/github.com/mgechev/revive/rule/modifies-value-receiver.go

@@ -0,0 +1,134 @@
+package rule
+
+import (
+	"go/ast"
+	"strings"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// ModifiesValRecRule lints assignments to value method-receivers.
+type ModifiesValRecRule struct{}
+
+// Apply applies the rule to given file.
+func (r *ModifiesValRecRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	onFailure := func(failure lint.Failure) {
+		failures = append(failures, failure)
+	}
+
+	w := lintModifiesValRecRule{file: file, onFailure: onFailure}
+	file.Pkg.TypeCheck()
+	ast.Walk(w, file.AST)
+
+	return failures
+}
+
+// Name returns the rule name.
+func (r *ModifiesValRecRule) Name() string {
+	return "modifies-value-receiver"
+}
+
+type lintModifiesValRecRule struct {
+	file      *lint.File
+	onFailure func(lint.Failure)
+}
+
+func (w lintModifiesValRecRule) Visit(node ast.Node) ast.Visitor {
+	switch n := node.(type) {
+	case *ast.FuncDecl:
+		if n.Recv == nil {
+			return nil // skip, not a method
+		}
+
+		receiver := n.Recv.List[0]
+		if _, ok := receiver.Type.(*ast.StarExpr); ok {
+			return nil // skip, method with pointer receiver
+		}
+
+		if w.skipType(receiver.Type) {
+			return nil // skip, receiver is a map or array
+		}
+
+		if len(receiver.Names) < 1 {
+			return nil // skip, anonymous receiver
+		}
+
+		receiverName := receiver.Names[0].Name
+		if receiverName == "_" {
+			return nil // skip, anonymous receiver
+		}
+
+		fselect := func(n ast.Node) bool {
+			// look for assignments with the receiver in the right hand
+			asgmt, ok := n.(*ast.AssignStmt)
+			if !ok {
+				return false
+			}
+
+			for _, exp := range asgmt.Lhs {
+				switch e := exp.(type) {
+				case *ast.IndexExpr: // receiver...[] = ...
+					continue
+				case *ast.StarExpr: // *receiver = ...
+					continue
+				case *ast.SelectorExpr: // receiver.field = ...
+					name := w.getNameFromExpr(e.X)
+					if name == "" || name != receiverName {
+						continue
+					}
+
+					if w.skipType(ast.Expr(e.Sel)) {
+						continue
+					}
+
+				case *ast.Ident: // receiver := ...
+					if e.Name != receiverName {
+						continue
+					}
+				default:
+					continue
+				}
+
+				return true
+			}
+
+			return false
+		}
+
+		assignmentsToReceiver := pick(n.Body, fselect, nil)
+
+		for _, assignment := range assignmentsToReceiver {
+			w.onFailure(lint.Failure{
+				Node:       assignment,
+				Confidence: 1,
+				Failure:    "suspicious assignment to a by-value method receiver",
+			})
+		}
+	}
+
+	return w
+}
+
+func (w lintModifiesValRecRule) skipType(t ast.Expr) bool {
+	rt := w.file.Pkg.TypeOf(t)
+	if rt == nil {
+		return false
+	}
+
+	rt = rt.Underlying()
+	rtName := rt.String()
+
+	// skip when receiver is a map or array
+	return strings.HasPrefix(rtName, "[]") || strings.HasPrefix(rtName, "map[")
+}
+
+func (lintModifiesValRecRule) getNameFromExpr(ie ast.Expr) string {
+	ident, ok := ie.(*ast.Ident)
+	if !ok {
+		return ""
+	}
+
+	return ident.Name
+}

vendor/github.com/mgechev/revive/rule/package-comments.go

@@ -0,0 +1,121 @@
+package rule
+
+import (
+	"fmt"
+	"go/ast"
+	"go/token"
+	"strings"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// PackageCommentsRule lints the package comments. It complains if
+// there is no package comment, or if it is not of the right form.
+// This has a notable false positive in that a package comment
+// could rightfully appear in a different file of the same package,
+// but that's not easy to fix since this linter is file-oriented.
+type PackageCommentsRule struct{}
+
+// Apply applies the rule to given file.
+func (r *PackageCommentsRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	if isTest(file) {
+		return failures
+	}
+
+	onFailure := func(failure lint.Failure) {
+		failures = append(failures, failure)
+	}
+
+	fileAst := file.AST
+	w := &lintPackageComments{fileAst, file, onFailure}
+	ast.Walk(w, fileAst)
+	return failures
+}
+
+// Name returns the rule name.
+func (r *PackageCommentsRule) Name() string {
+	return "package-comments"
+}
+
+type lintPackageComments struct {
+	fileAst   *ast.File
+	file      *lint.File
+	onFailure func(lint.Failure)
+}
+
+func (l *lintPackageComments) Visit(_ ast.Node) ast.Visitor {
+	if l.file.IsTest() {
+		return nil
+	}
+
+	const ref = styleGuideBase + "#package-comments"
+	prefix := "Package " + l.fileAst.Name.Name + " "
+
+	// Look for a detached package comment.
+	// First, scan for the last comment that occurs before the "package" keyword.
+	var lastCG *ast.CommentGroup
+	for _, cg := range l.fileAst.Comments {
+		if cg.Pos() > l.fileAst.Package {
+			// Gone past "package" keyword.
+			break
+		}
+		lastCG = cg
+	}
+	if lastCG != nil && strings.HasPrefix(lastCG.Text(), prefix) {
+		endPos := l.file.ToPosition(lastCG.End())
+		pkgPos := l.file.ToPosition(l.fileAst.Package)
+		if endPos.Line+1 < pkgPos.Line {
+			// There isn't a great place to anchor this error;
+			// the start of the blank lines between the doc and the package statement
+			// is at least pointing at the location of the problem.
+			pos := token.Position{
+				Filename: endPos.Filename,
+				// Offset not set; it is non-trivial, and doesn't appear to be needed.
+				Line:   endPos.Line + 1,
+				Column: 1,
+			}
+			l.onFailure(lint.Failure{
+				Category: "comments",
+				Position: lint.FailurePosition{
+					Start: pos,
+					End:   pos,
+				},
+				Confidence: 0.9,
+				Failure:    "package comment is detached; there should be no blank lines between it and the package statement",
+			})
+			return nil
+		}
+	}
+
+	if l.fileAst.Doc == nil {
+		l.onFailure(lint.Failure{
+			Category:   "comments",
+			Node:       l.fileAst,
+			Confidence: 0.2,
+			Failure:    "should have a package comment, unless it's in another file for this package",
+		})
+		return nil
+	}
+	s := l.fileAst.Doc.Text()
+	if ts := strings.TrimLeft(s, " \t"); ts != s {
+		l.onFailure(lint.Failure{
+			Category:   "comments",
+			Node:       l.fileAst.Doc,
+			Confidence: 1,
+			Failure:    "package comment should not have leading space",
+		})
+		s = ts
+	}
+	// Only non-main packages need to keep to this form.
+	if !l.file.Pkg.IsMain() && !strings.HasPrefix(s, prefix) {
+		l.onFailure(lint.Failure{
+			Category:   "comments",
+			Node:       l.fileAst.Doc,
+			Confidence: 1,
+			Failure:    fmt.Sprintf(`package comment should be of the form "%s..."`, prefix),
+		})
+	}
+	return nil
+}

vendor/github.com/mgechev/revive/rule/range-val-address.go

@@ -0,0 +1,113 @@
+package rule
+
+import (
+	"fmt"
+	"go/ast"
+	"go/token"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// RangeValAddress lints
+type RangeValAddress struct{}
+
+// Apply applies the rule to given file.
+func (r *RangeValAddress) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	walker := rangeValAddress{
+		onFailure: func(failure lint.Failure) {
+			failures = append(failures, failure)
+		},
+	}
+
+	ast.Walk(walker, file.AST)
+
+	return failures
+}
+
+// Name returns the rule name.
+func (r *RangeValAddress) Name() string {
+	return "range-val-address"
+}
+
+type rangeValAddress struct {
+	onFailure func(lint.Failure)
+}
+
+func (w rangeValAddress) Visit(node ast.Node) ast.Visitor {
+	n, ok := node.(*ast.RangeStmt)
+	if !ok {
+		return w
+	}
+
+	value, ok := n.Value.(*ast.Ident)
+	if !ok {
+		return w
+	}
+
+	ast.Walk(rangeBodyVisitor{
+		valueID:   value.Obj,
+		onFailure: w.onFailure,
+	}, n.Body)
+
+	return w
+}
+
+type rangeBodyVisitor struct {
+	valueID   *ast.Object
+	onFailure func(lint.Failure)
+}
+
+func (bw rangeBodyVisitor) Visit(node ast.Node) ast.Visitor {
+	asgmt, ok := node.(*ast.AssignStmt)
+	if !ok {
+		return bw
+	}
+
+	for _, exp := range asgmt.Lhs {
+		e, ok := exp.(*ast.IndexExpr)
+		if !ok {
+			continue
+		}
+		if bw.isAccessingRangeValueAddress(e.Index) { // e.g. a[&value]...
+			bw.onFailure(bw.newFailure(e.Index))
+		}
+	}
+
+	for _, exp := range asgmt.Rhs {
+		switch e := exp.(type) {
+		case *ast.UnaryExpr: // e.g. ...&value
+			if bw.isAccessingRangeValueAddress(e) {
+				bw.onFailure(bw.newFailure(e))
+			}
+		case *ast.CallExpr:
+			if fun, ok := e.Fun.(*ast.Ident); ok && fun.Name == "append" { // e.g. ...append(arr, &value)
+				for _, v := range e.Args {
+					if bw.isAccessingRangeValueAddress(v) {
+						bw.onFailure(bw.newFailure(e))
+					}
+				}
+			}
+		}
+	}
+	return bw
+}
+
+func (bw rangeBodyVisitor) isAccessingRangeValueAddress(exp ast.Expr) bool {
+	u, ok := exp.(*ast.UnaryExpr)
+	if !ok {
+		return false
+	}
+
+	v, ok := u.X.(*ast.Ident)
+	return ok && u.Op == token.AND && v.Obj == bw.valueID
+}
+
+func (bw rangeBodyVisitor) newFailure(node ast.Node) lint.Failure {
+	return lint.Failure{
+		Node:       node,
+		Confidence: 1,
+		Failure:    fmt.Sprintf("suspicious assignment of '%s'. range-loop variables always have the same address", bw.valueID.Name),
+	}
+}

vendor/github.com/mgechev/revive/rule/range-val-in-closure.go

@@ -0,0 +1,111 @@
+package rule
+
+import (
+	"fmt"
+	"go/ast"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// RangeValInClosureRule lints given else constructs.
+type RangeValInClosureRule struct{}
+
+// Apply applies the rule to given file.
+func (r *RangeValInClosureRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	walker := rangeValInClosure{
+		onFailure: func(failure lint.Failure) {
+			failures = append(failures, failure)
+		},
+	}
+
+	ast.Walk(walker, file.AST)
+
+	return failures
+}
+
+// Name returns the rule name.
+func (r *RangeValInClosureRule) Name() string {
+	return "range-val-in-closure"
+}
+
+type rangeValInClosure struct {
+	onFailure func(lint.Failure)
+}
+
+func (w rangeValInClosure) Visit(node ast.Node) ast.Visitor {
+
+	// Find the variables updated by the loop statement.
+	var vars []*ast.Ident
+	addVar := func(expr ast.Expr) {
+		if id, ok := expr.(*ast.Ident); ok {
+			vars = append(vars, id)
+		}
+	}
+	var body *ast.BlockStmt
+	switch n := node.(type) {
+	case *ast.RangeStmt:
+		body = n.Body
+		addVar(n.Key)
+		addVar(n.Value)
+	case *ast.ForStmt:
+		body = n.Body
+		switch post := n.Post.(type) {
+		case *ast.AssignStmt:
+			// e.g. for p = head; p != nil; p = p.next
+			for _, lhs := range post.Lhs {
+				addVar(lhs)
+			}
+		case *ast.IncDecStmt:
+			// e.g. for i := 0; i < n; i++
+			addVar(post.X)
+		}
+	}
+	if vars == nil {
+		return w
+	}
+
+	// Inspect a go or defer statement
+	// if it's the last one in the loop body.
+	// (We give up if there are following statements,
+	// because it's hard to prove go isn't followed by wait,
+	// or defer by return.)
+	if len(body.List) == 0 {
+		return w
+	}
+	var last *ast.CallExpr
+	switch s := body.List[len(body.List)-1].(type) {
+	case *ast.GoStmt:
+		last = s.Call
+	case *ast.DeferStmt:
+		last = s.Call
+	default:
+		return w
+	}
+	lit, ok := last.Fun.(*ast.FuncLit)
+	if !ok {
+		return w
+	}
+	if lit.Type == nil {
+		// Not referring to a variable (e.g. struct field name)
+		return w
+	}
+	ast.Inspect(lit.Body, func(n ast.Node) bool {
+		id, ok := n.(*ast.Ident)
+		if !ok || id.Obj == nil {
+			return true
+		}
+		for _, v := range vars {
+			if v.Obj == id.Obj {
+				w.onFailure(lint.Failure{
+					Confidence: 1,
+					Failure:    fmt.Sprintf("loop variable %v captured by func literal", id.Name),
+					Node:       n,
+				})
+			}
+		}
+		return true
+	})
+	return w
+}

vendor/github.com/mgechev/revive/rule/range.go

@@ -0,0 +1,82 @@
+package rule
+
+import (
+	"fmt"
+	"go/ast"
+	"strings"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// RangeRule lints given else constructs.
+type RangeRule struct{}
+
+// Apply applies the rule to given file.
+func (r *RangeRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	onFailure := func(failure lint.Failure) {
+		failures = append(failures, failure)
+	}
+
+	w := &lintRanges{file, onFailure}
+	ast.Walk(w, file.AST)
+	return failures
+}
+
+// Name returns the rule name.
+func (r *RangeRule) Name() string {
+	return "range"
+}
+
+type lintRanges struct {
+	file      *lint.File
+	onFailure func(lint.Failure)
+}
+
+func (w *lintRanges) Visit(node ast.Node) ast.Visitor {
+	rs, ok := node.(*ast.RangeStmt)
+	if !ok {
+		return w
+	}
+	if rs.Value == nil {
+		// for x = range m { ... }
+		return w // single var form
+	}
+	if !isIdent(rs.Value, "_") {
+		// for ?, y = range m { ... }
+		return w
+	}
+
+	newRS := *rs // shallow copy
+	newRS.Value = nil
+
+	w.onFailure(lint.Failure{
+		Failure:         fmt.Sprintf("should omit 2nd value from range; this loop is equivalent to `for %s %s range ...`", w.file.Render(rs.Key), rs.Tok),
+		Confidence:      1,
+		Node:            rs.Value,
+		ReplacementLine: firstLineOf(w.file, &newRS, rs),
+	})
+
+	return w
+}
+
+func firstLineOf(f *lint.File, node, match ast.Node) string {
+	line := f.Render(node)
+	if i := strings.Index(line, "\n"); i >= 0 {
+		line = line[:i]
+	}
+	return indentOf(f, match) + line
+}
+
+func indentOf(f *lint.File, node ast.Node) string {
+	line := srcLine(f.Content(), f.ToPosition(node.Pos()))
+	for i, r := range line {
+		switch r {
+		case ' ', '\t':
+		default:
+			return line[:i]
+		}
+	}
+	return line // unusual or empty line
+}

vendor/github.com/mgechev/revive/rule/receiver-naming.go

@@ -0,0 +1,81 @@
+package rule
+
+import (
+	"fmt"
+	"go/ast"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// ReceiverNamingRule lints given else constructs.
+type ReceiverNamingRule struct{}
+
+// Apply applies the rule to given file.
+func (r *ReceiverNamingRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	fileAst := file.AST
+	walker := lintReceiverName{
+		onFailure: func(failure lint.Failure) {
+			failures = append(failures, failure)
+		},
+		typeReceiver: map[string]string{},
+	}
+
+	ast.Walk(walker, fileAst)
+
+	return failures
+}
+
+// Name returns the rule name.
+func (r *ReceiverNamingRule) Name() string {
+	return "receiver-naming"
+}
+
+type lintReceiverName struct {
+	onFailure    func(lint.Failure)
+	typeReceiver map[string]string
+}
+
+func (w lintReceiverName) Visit(n ast.Node) ast.Visitor {
+	fn, ok := n.(*ast.FuncDecl)
+	if !ok || fn.Recv == nil || len(fn.Recv.List) == 0 {
+		return w
+	}
+	names := fn.Recv.List[0].Names
+	if len(names) < 1 {
+		return w
+	}
+	name := names[0].Name
+	const ref = styleGuideBase + "#receiver-names"
+	if name == "_" {
+		w.onFailure(lint.Failure{
+			Node:       n,
+			Confidence: 1,
+			Category:   "naming",
+			Failure:    "receiver name should not be an underscore, omit the name if it is unused",
+		})
+		return w
+	}
+	if name == "this" || name == "self" {
+		w.onFailure(lint.Failure{
+			Node:       n,
+			Confidence: 1,
+			Category:   "naming",
+			Failure:    `receiver name should be a reflection of its identity; don't use generic names such as "this" or "self"`,
+		})
+		return w
+	}
+	recv := receiverType(fn)
+	if prev, ok := w.typeReceiver[recv]; ok && prev != name {
+		w.onFailure(lint.Failure{
+			Node:       n,
+			Confidence: 1,
+			Category:   "naming",
+			Failure:    fmt.Sprintf("receiver name %s should be consistent with previous receiver name %s for %s", name, prev, recv),
+		})
+		return w
+	}
+	w.typeReceiver[recv] = name
+	return w
+}

vendor/github.com/mgechev/revive/rule/redefines-builtin-id.go

@@ -0,0 +1,145 @@
+package rule
+
+import (
+	"fmt"
+	"github.com/mgechev/revive/lint"
+	"go/ast"
+	"go/token"
+)
+
+// RedefinesBuiltinIDRule warns when a builtin identifier is shadowed.
+type RedefinesBuiltinIDRule struct{}
+
+// Apply applies the rule to given file.
+func (r *RedefinesBuiltinIDRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	var builtInConstAndVars = map[string]bool{
+		"true":  true,
+		"false": true,
+		"iota":  true,
+		"nil":   true,
+	}
+
+	var builtFunctions = map[string]bool{
+		"append":  true,
+		"cap":     true,
+		"close":   true,
+		"complex": true,
+		"copy":    true,
+		"delete":  true,
+		"imag":    true,
+		"len":     true,
+		"make":    true,
+		"new":     true,
+		"panic":   true,
+		"print":   true,
+		"println": true,
+		"real":    true,
+		"recover": true,
+	}
+
+	var builtInTypes = map[string]bool{
+		"ComplexType": true,
+		"FloatType":   true,
+		"IntegerType": true,
+		"Type":        true,
+		"Type1":       true,
+		"bool":        true,
+		"byte":        true,
+		"complex128":  true,
+		"complex64":   true,
+		"error":       true,
+		"float32":     true,
+		"float64":     true,
+		"int":         true,
+		"int16":       true,
+		"int32":       true,
+		"int64":       true,
+		"int8":        true,
+		"rune":        true,
+		"string":      true,
+		"uint":        true,
+		"uint16":      true,
+		"uint32":      true,
+		"uint64":      true,
+		"uint8":       true,
+		"uintptr":     true,
+	}
+
+	onFailure := func(failure lint.Failure) {
+		failures = append(failures, failure)
+	}
+
+	astFile := file.AST
+	w := &lintRedefinesBuiltinID{builtInConstAndVars, builtFunctions, builtInTypes, onFailure}
+	ast.Walk(w, astFile)
+
+	return failures
+}
+
+// Name returns the rule name.
+func (r *RedefinesBuiltinIDRule) Name() string {
+	return "redefines-builtin-id"
+}
+
+type lintRedefinesBuiltinID struct {
+	constsAndVars map[string]bool
+	funcs         map[string]bool
+	types         map[string]bool
+	onFailure     func(lint.Failure)
+}
+
+func (w *lintRedefinesBuiltinID) Visit(node ast.Node) ast.Visitor {
+	switch n := node.(type) {
+	case *ast.GenDecl:
+		if n.Tok != token.TYPE {
+			return nil // skip if not type declaration
+		}
+		typeSpec, ok := n.Specs[0].(*ast.TypeSpec)
+		if !ok {
+			return nil
+		}
+		id := typeSpec.Name.Name
+		if w.types[id] {
+			w.addFailure(n, fmt.Sprintf("redefinition of the built-in type %s", id))
+		}
+	case *ast.FuncDecl:
+		if n.Recv != nil {
+			return w // skip methods
+		}
+
+		id := n.Name.Name
+		if w.funcs[id] {
+			w.addFailure(n, fmt.Sprintf("redefinition of the built-in function %s", id))
+		}
+	case *ast.AssignStmt:
+		for _, e := range n.Lhs {
+			id, ok := e.(*ast.Ident)
+			if !ok {
+				continue
+			}
+
+			if w.constsAndVars[id.Name] {
+				var msg string
+				if n.Tok == token.DEFINE {
+					msg = fmt.Sprintf("assignment creates a shadow of built-in identifier %s", id.Name)
+				} else {
+					msg = fmt.Sprintf("assignment modifies built-in identifier %s", id.Name)
+				}
+				w.addFailure(n, msg)
+			}
+		}
+	}
+
+	return w
+}
+
+func (w lintRedefinesBuiltinID) addFailure(node ast.Node, msg string) {
+	w.onFailure(lint.Failure{
+		Confidence: 1,
+		Node:       node,
+		Category:   "logic",
+		Failure:    msg,
+	})
+}

vendor/github.com/mgechev/revive/rule/string-of-int.go

@@ -0,0 +1,95 @@
+package rule
+
+import (
+	"go/ast"
+	"go/types"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// StringOfIntRule warns when logic expressions contains Boolean literals.
+type StringOfIntRule struct{}
+
+// Apply applies the rule to given file.
+func (r *StringOfIntRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	onFailure := func(failure lint.Failure) {
+		failures = append(failures, failure)
+	}
+
+	astFile := file.AST
+	file.Pkg.TypeCheck()
+
+	w := &lintStringInt{file, onFailure}
+	ast.Walk(w, astFile)
+
+	return failures
+}
+
+// Name returns the rule name.
+func (r *StringOfIntRule) Name() string {
+	return "string-of-int"
+}
+
+type lintStringInt struct {
+	file      *lint.File
+	onFailure func(lint.Failure)
+}
+
+func (w *lintStringInt) Visit(node ast.Node) ast.Visitor {
+	ce, ok := node.(*ast.CallExpr)
+	if !ok {
+		return w
+	}
+
+	if !w.isCallStringCast(ce.Fun) {
+		return w
+	}
+
+	if !w.isIntExpression(ce.Args) {
+		return w
+	}
+
+	w.onFailure(lint.Failure{
+		Confidence: 1,
+		Node:       ce,
+		Failure:    "dubious convertion of an integer into a string, use strconv.Itoa",
+	})
+
+	return w
+}
+
+func (w *lintStringInt) isCallStringCast(e ast.Expr) bool {
+	t := w.file.Pkg.TypeOf(e)
+	if t == nil {
+		return false
+	}
+
+	tb, _ := t.Underlying().(*types.Basic)
+
+	return tb != nil && tb.Kind() == types.String
+}
+
+func (w *lintStringInt) isIntExpression(es []ast.Expr) bool {
+	if len(es) != 1 {
+		return false
+	}
+
+	t := w.file.Pkg.TypeOf(es[0])
+	if t == nil {
+		return false
+	}
+
+	ut, _ := t.Underlying().(*types.Basic)
+	if ut == nil || ut.Info()&types.IsInteger == 0 {
+		return false
+	}
+
+	switch ut.Kind() {
+	case types.Byte, types.Rune, types.UntypedRune:
+		return false
+	}
+
+	return true
+}

vendor/github.com/mgechev/revive/rule/struct-tag.go

@@ -0,0 +1,236 @@
+package rule
+
+import (
+	"fmt"
+	"go/ast"
+	"strconv"
+	"strings"
+
+	"github.com/fatih/structtag"
+	"github.com/mgechev/revive/lint"
+)
+
+// StructTagRule lints struct tags.
+type StructTagRule struct{}
+
+// Apply applies the rule to given file.
+func (r *StructTagRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	onFailure := func(failure lint.Failure) {
+		failures = append(failures, failure)
+	}
+
+	w := lintStructTagRule{onFailure: onFailure}
+
+	ast.Walk(w, file.AST)
+
+	return failures
+}
+
+// Name returns the rule name.
+func (r *StructTagRule) Name() string {
+	return "struct-tag"
+}
+
+type lintStructTagRule struct {
+	onFailure  func(lint.Failure)
+	usedTagNbr map[string]bool // list of used tag numbers
+}
+
+func (w lintStructTagRule) Visit(node ast.Node) ast.Visitor {
+	switch n := node.(type) {
+	case *ast.StructType:
+		if n.Fields == nil || n.Fields.NumFields() < 1 {
+			return nil // skip empty structs
+		}
+		w.usedTagNbr = map[string]bool{} // init
+		for _, f := range n.Fields.List {
+			if f.Tag != nil {
+				w.checkTaggedField(f)
+			}
+		}
+	}
+
+	return w
+
+}
+
+// checkTaggedField checks the tag of the given field.
+// precondition: the field has a tag
+func (w lintStructTagRule) checkTaggedField(f *ast.Field) {
+	if len(f.Names) > 0 && !f.Names[0].IsExported() {
+		w.addFailure(f, "tag on not-exported field "+f.Names[0].Name)
+	}
+
+	tags, err := structtag.Parse(strings.Trim(f.Tag.Value, "`"))
+	if err != nil || tags == nil {
+		w.addFailure(f.Tag, "malformed tag")
+		return
+	}
+
+	for _, tag := range tags.Tags() {
+		switch key := tag.Key; key {
+		case "asn1":
+			msg, ok := w.checkASN1Tag(f.Type, tag)
+			if !ok {
+				w.addFailure(f.Tag, msg)
+			}
+		case "bson":
+			msg, ok := w.checkBSONTag(tag.Options)
+			if !ok {
+				w.addFailure(f.Tag, msg)
+			}
+		case "default":
+			if !w.typeValueMatch(f.Type, tag.Name) {
+				w.addFailure(f.Tag, "field's type and default value's type mismatch")
+			}
+		case "json":
+			msg, ok := w.checkJSONTag(tag.Name, tag.Options)
+			if !ok {
+				w.addFailure(f.Tag, msg)
+			}
+		case "protobuf":
+			// Not implemented yet
+		case "required":
+			if tag.Name != "true" && tag.Name != "false" {
+				w.addFailure(f.Tag, "required should be 'true' or 'false'")
+			}
+		case "xml":
+			msg, ok := w.checkXMLTag(tag.Options)
+			if !ok {
+				w.addFailure(f.Tag, msg)
+			}
+		case "yaml":
+			msg, ok := w.checkYAMLTag(tag.Options)
+			if !ok {
+				w.addFailure(f.Tag, msg)
+			}
+		default:
+			// unknown key
+		}
+	}
+}
+
+func (w lintStructTagRule) checkASN1Tag(t ast.Expr, tag *structtag.Tag) (string, bool) {
+	checkList := append(tag.Options, tag.Name)
+	for _, opt := range checkList {
+		switch opt {
+		case "application", "explicit", "generalized", "ia5", "omitempty", "optional", "set", "utf8":
+
+		default:
+			if strings.HasPrefix(opt, "tag:") {
+				parts := strings.Split(opt, ":")
+				tagNumber := parts[1]
+				if w.usedTagNbr[tagNumber] {
+					return fmt.Sprintf("duplicated tag number %s", tagNumber), false
+				}
+				w.usedTagNbr[tagNumber] = true
+
+				continue
+			}
+
+			if strings.HasPrefix(opt, "default:") {
+				parts := strings.Split(opt, ":")
+				if len(parts) < 2 {
+					return "malformed default for ASN1 tag", false
+				}
+				if !w.typeValueMatch(t, parts[1]) {
+					return "field's type and default value's type mismatch", false
+				}
+
+				continue
+			}
+
+			return fmt.Sprintf("unknown option '%s' in ASN1 tag", opt), false
+		}
+	}
+
+	return "", true
+}
+
+func (w lintStructTagRule) checkBSONTag(options []string) (string, bool) {
+	for _, opt := range options {
+		switch opt {
+		case "inline", "minsize", "omitempty":
+		default:
+			return fmt.Sprintf("unknown option '%s' in BSON tag", opt), false
+		}
+	}
+
+	return "", true
+}
+
+func (w lintStructTagRule) checkJSONTag(name string, options []string) (string, bool) {
+	for _, opt := range options {
+		switch opt {
+		case "omitempty", "string":
+		case "":
+			// special case for JSON key "-"
+			if name != "-" {
+				return "option can not be empty in JSON tag", false	
+			}
+		default:
+			return fmt.Sprintf("unknown option '%s' in JSON tag", opt), false
+		}
+	}
+
+	return "", true
+}
+
+func (w lintStructTagRule) checkXMLTag(options []string) (string, bool) {
+	for _, opt := range options {
+		switch opt {
+		case "any", "attr", "cdata", "chardata", "comment", "innerxml", "omitempty", "typeattr":
+		default:
+			return fmt.Sprintf("unknown option '%s' in XML tag", opt), false
+		}
+	}
+
+	return "", true
+}
+
+func (w lintStructTagRule) checkYAMLTag(options []string) (string, bool) {
+	for _, opt := range options {
+		switch opt {
+		case "flow", "inline", "omitempty":
+		default:
+			return fmt.Sprintf("unknown option '%s' in YAML tag", opt), false
+		}
+	}
+
+	return "", true
+}
+
+func (w lintStructTagRule) typeValueMatch(t ast.Expr, val string) bool {
+	tID, ok := t.(*ast.Ident)
+	if !ok {
+		return true
+	}
+
+	typeMatches := true
+	switch tID.Name {
+	case "bool":
+		typeMatches = val == "true" || val == "false"
+	case "float64":
+		_, err := strconv.ParseFloat(val, 64)
+		typeMatches = err == nil
+	case "int":
+		_, err := strconv.ParseInt(val, 10, 64)
+		typeMatches = err == nil
+	case "string":
+	case "nil":
+	default:
+		// unchecked type
+	}
+
+	return typeMatches
+}
+
+func (w lintStructTagRule) addFailure(n ast.Node, msg string) {
+	w.onFailure(lint.Failure{
+		Node:       n,
+		Failure:    msg,
+		Confidence: 1,
+	})
+}

vendor/github.com/mgechev/revive/rule/superfluous-else.go

@@ -0,0 +1,114 @@
+package rule
+
+import (
+	"fmt"
+	"go/ast"
+	"go/token"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// SuperfluousElseRule lints given else constructs.
+type SuperfluousElseRule struct{}
+
+// Apply applies the rule to given file.
+func (r *SuperfluousElseRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+	onFailure := func(failure lint.Failure) {
+		failures = append(failures, failure)
+	}
+
+	var branchingFunctions = map[string]map[string]bool{
+		"os": map[string]bool{"Exit": true},
+		"log": map[string]bool{
+			"Fatal":   true,
+			"Fatalf":  true,
+			"Fatalln": true,
+			"Panic":   true,
+			"Panicf":  true,
+			"Panicln": true,
+		},
+	}
+
+	w := lintSuperfluousElse{make(map[*ast.IfStmt]bool), onFailure, branchingFunctions}
+	ast.Walk(w, file.AST)
+	return failures
+}
+
+// Name returns the rule name.
+func (r *SuperfluousElseRule) Name() string {
+	return "superfluous-else"
+}
+
+type lintSuperfluousElse struct {
+	ignore             map[*ast.IfStmt]bool
+	onFailure          func(lint.Failure)
+	branchingFunctions map[string]map[string]bool
+}
+
+func (w lintSuperfluousElse) Visit(node ast.Node) ast.Visitor {
+	ifStmt, ok := node.(*ast.IfStmt)
+	if !ok || ifStmt.Else == nil {
+		return w
+	}
+	if w.ignore[ifStmt] {
+		if elseif, ok := ifStmt.Else.(*ast.IfStmt); ok {
+			w.ignore[elseif] = true
+		}
+		return w
+	}
+	if elseif, ok := ifStmt.Else.(*ast.IfStmt); ok {
+		w.ignore[elseif] = true
+		return w
+	}
+	if _, ok := ifStmt.Else.(*ast.BlockStmt); !ok {
+		// only care about elses without conditions
+		return w
+	}
+	if len(ifStmt.Body.List) == 0 {
+		return w
+	}
+	shortDecl := false // does the if statement have a ":=" initialization statement?
+	if ifStmt.Init != nil {
+		if as, ok := ifStmt.Init.(*ast.AssignStmt); ok && as.Tok == token.DEFINE {
+			shortDecl = true
+		}
+	}
+	extra := ""
+	if shortDecl {
+		extra = " (move short variable declaration to its own line if necessary)"
+	}
+
+	lastStmt := ifStmt.Body.List[len(ifStmt.Body.List)-1]
+	switch stmt := lastStmt.(type) {
+	case *ast.BranchStmt:
+		token := stmt.Tok.String()
+		if token != "fallthrough" {
+			w.onFailure(newFailure(ifStmt.Else, "if block ends with a "+token+" statement, so drop this else and outdent its block"+extra))
+		}
+	case *ast.ExprStmt:
+		if ce, ok := stmt.X.(*ast.CallExpr); ok { // it's a function call
+			if fc, ok := ce.Fun.(*ast.SelectorExpr); ok {
+				if id, ok := fc.X.(*ast.Ident); ok {
+					fn := fc.Sel.Name
+					pkg := id.Name
+					if w.branchingFunctions[pkg][fn] { // it's a call to a branching function
+						w.onFailure(
+							newFailure(ifStmt.Else, fmt.Sprintf("if block ends with call to %s.%s function, so drop this else and outdent its block%s", pkg, fn, extra)))
+					}
+				}
+			}
+		}
+	}
+
+	return w
+}
+
+func newFailure(node ast.Node, msg string) lint.Failure {
+	return lint.Failure{
+		Confidence: 1,
+		Node:       node,
+		Category:   "indent",
+		Failure:    msg,
+	}
+}

vendor/github.com/mgechev/revive/rule/time-naming.go

@@ -0,0 +1,93 @@
+package rule
+
+import (
+	"fmt"
+	"go/ast"
+	"go/types"
+	"strings"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// TimeNamingRule lints given else constructs.
+type TimeNamingRule struct{}
+
+// Apply applies the rule to given file.
+func (r *TimeNamingRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	onFailure := func(failure lint.Failure) {
+		failures = append(failures, failure)
+	}
+
+	w := &lintTimeNames{file, onFailure}
+
+	file.Pkg.TypeCheck()
+	ast.Walk(w, file.AST)
+	return failures
+}
+
+// Name returns the rule name.
+func (r *TimeNamingRule) Name() string {
+	return "time-naming"
+}
+
+type lintTimeNames struct {
+	file      *lint.File
+	onFailure func(lint.Failure)
+}
+
+func (w *lintTimeNames) Visit(node ast.Node) ast.Visitor {
+	v, ok := node.(*ast.ValueSpec)
+	if !ok {
+		return w
+	}
+	for _, name := range v.Names {
+		origTyp := w.file.Pkg.TypeOf(name)
+		// Look for time.Duration or *time.Duration;
+		// the latter is common when using flag.Duration.
+		typ := origTyp
+		if pt, ok := typ.(*types.Pointer); ok {
+			typ = pt.Elem()
+		}
+		if !isNamedType(typ, "time", "Duration") {
+			continue
+		}
+		suffix := ""
+		for _, suf := range timeSuffixes {
+			if strings.HasSuffix(name.Name, suf) {
+				suffix = suf
+				break
+			}
+		}
+		if suffix == "" {
+			continue
+		}
+		w.onFailure(lint.Failure{
+			Category:   "time",
+			Confidence: 0.9,
+			Node:       v,
+			Failure:    fmt.Sprintf("var %s is of type %v; don't use unit-specific suffix %q", name.Name, origTyp, suffix),
+		})
+	}
+	return w
+}
+
+// timeSuffixes is a list of name suffixes that imply a time unit.
+// This is not an exhaustive list.
+var timeSuffixes = []string{
+	"Sec", "Secs", "Seconds",
+	"Msec", "Msecs",
+	"Milli", "Millis", "Milliseconds",
+	"Usec", "Usecs", "Microseconds",
+	"MS", "Ms",
+}
+
+func isNamedType(typ types.Type, importPath, name string) bool {
+	n, ok := typ.(*types.Named)
+	if !ok {
+		return false
+	}
+	tn := n.Obj()
+	return tn != nil && tn.Pkg() != nil && tn.Pkg().Path() == importPath && tn.Name() == name
+}

vendor/github.com/mgechev/revive/rule/unexported-return.go

@@ -0,0 +1,106 @@
+package rule
+
+import (
+	"fmt"
+	"go/ast"
+	"go/types"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// UnexportedReturnRule lints given else constructs.
+type UnexportedReturnRule struct{}
+
+// Apply applies the rule to given file.
+func (r *UnexportedReturnRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	fileAst := file.AST
+	walker := lintUnexportedReturn{
+		file:    file,
+		fileAst: fileAst,
+		onFailure: func(failure lint.Failure) {
+			failures = append(failures, failure)
+		},
+	}
+
+	file.Pkg.TypeCheck()
+	ast.Walk(walker, fileAst)
+
+	return failures
+}
+
+// Name returns the rule name.
+func (r *UnexportedReturnRule) Name() string {
+	return "unexported-return"
+}
+
+type lintUnexportedReturn struct {
+	file      *lint.File
+	fileAst   *ast.File
+	onFailure func(lint.Failure)
+}
+
+func (w lintUnexportedReturn) Visit(n ast.Node) ast.Visitor {
+	fn, ok := n.(*ast.FuncDecl)
+	if !ok {
+		return w
+	}
+	if fn.Type.Results == nil {
+		return nil
+	}
+	if !fn.Name.IsExported() {
+		return nil
+	}
+	thing := "func"
+	if fn.Recv != nil && len(fn.Recv.List) > 0 {
+		thing = "method"
+		if !ast.IsExported(receiverType(fn)) {
+			// Don't report exported methods of unexported types,
+			// such as private implementations of sort.Interface.
+			return nil
+		}
+	}
+	for _, ret := range fn.Type.Results.List {
+		typ := w.file.Pkg.TypeOf(ret.Type)
+		if exportedType(typ) {
+			continue
+		}
+		w.onFailure(lint.Failure{
+			Category:   "unexported-type-in-api",
+			Node:       ret.Type,
+			Confidence: 0.8,
+			Failure: fmt.Sprintf("exported %s %s returns unexported type %s, which can be annoying to use",
+				thing, fn.Name.Name, typ),
+		})
+		break // only flag one
+	}
+	return nil
+}
+
+// exportedType reports whether typ is an exported type.
+// It is imprecise, and will err on the side of returning true,
+// such as for composite types.
+func exportedType(typ types.Type) bool {
+	switch T := typ.(type) {
+	case *types.Named:
+		obj := T.Obj()
+		switch {
+		// Builtin types have no package.
+		case obj.Pkg() == nil:
+		case obj.Exported():
+		default:
+			_, ok := T.Underlying().(*types.Interface)
+			return ok
+		}
+		return true
+	case *types.Map:
+		return exportedType(T.Key()) && exportedType(T.Elem())
+	case interface {
+		Elem() types.Type
+	}: // array, slice, pointer, chan
+		return exportedType(T.Elem())
+	}
+	// Be conservative about other types, such as struct, interface, etc.
+	return true
+}

vendor/github.com/mgechev/revive/rule/unhandled-error.go

@@ -0,0 +1,120 @@
+package rule
+
+import (
+	"fmt"
+	"go/ast"
+	"go/types"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// UnhandledErrorRule lints given else constructs.
+type UnhandledErrorRule struct{}
+
+type ignoreListType map[string]struct{}
+
+// Apply applies the rule to given file.
+func (r *UnhandledErrorRule) Apply(file *lint.File, args lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	ignoreList := make(ignoreListType, len(args))
+
+	for _, arg := range args {
+		argStr, ok := arg.(string)
+		if !ok {
+			panic(fmt.Sprintf("Invalid argument to the unhandled-error rule. Expecting a string, got %T", arg))
+		}
+
+		ignoreList[argStr] = struct{}{}
+	}
+
+	walker := &lintUnhandledErrors{
+		ignoreList: ignoreList,
+		pkg:        file.Pkg,
+		onFailure: func(failure lint.Failure) {
+			failures = append(failures, failure)
+		},
+	}
+
+	file.Pkg.TypeCheck()
+	ast.Walk(walker, file.AST)
+
+	return failures
+}
+
+// Name returns the rule name.
+func (r *UnhandledErrorRule) Name() string {
+	return "unhandled-error"
+}
+
+type lintUnhandledErrors struct {
+	ignoreList ignoreListType
+	pkg        *lint.Package
+	onFailure  func(lint.Failure)
+}
+
+// Visit looks for statements that are function calls.
+// If the called function returns a value of type error a failure will be created.
+func (w *lintUnhandledErrors) Visit(node ast.Node) ast.Visitor {
+	switch n := node.(type) {
+	case *ast.ExprStmt:
+		fCall, ok := n.X.(*ast.CallExpr)
+		if !ok {
+			return nil // not a function call
+		}
+
+		funcType := w.pkg.TypeOf(fCall)
+		if funcType == nil {
+			return nil // skip, type info not available
+		}
+
+		switch t := funcType.(type) {
+		case *types.Named:
+			if !w.isTypeError(t) {
+				return nil // func call does not return an error
+			}
+
+			w.addFailure(fCall)
+		default:
+			retTypes, ok := funcType.Underlying().(*types.Tuple)
+			if !ok {
+				return nil // skip, unable to retrieve return type of the called function
+			}
+
+			if w.returnsAnError(retTypes) {
+				w.addFailure(fCall)
+			}
+		}
+	}
+	return w
+}
+
+func (w *lintUnhandledErrors) addFailure(n *ast.CallExpr) {
+	funcName := gofmt(n.Fun)
+	if _, mustIgnore := w.ignoreList[funcName]; mustIgnore {
+		return
+	}
+
+	w.onFailure(lint.Failure{
+		Category:   "bad practice",
+		Confidence: 1,
+		Node:       n,
+		Failure:    fmt.Sprintf("Unhandled error in call to function %v", funcName),
+	})
+}
+
+func (*lintUnhandledErrors) isTypeError(t *types.Named) bool {
+	const errorTypeName = "_.error"
+
+	return t.Obj().Id() == errorTypeName
+}
+
+func (w *lintUnhandledErrors) returnsAnError(tt *types.Tuple) bool {
+	for i := 0; i < tt.Len(); i++ {
+		nt, ok := tt.At(i).Type().(*types.Named)
+		if ok && w.isTypeError(nt) {
+			return true
+		}
+	}
+	return false
+}

vendor/github.com/mgechev/revive/rule/unnecessary-stmt.go

@@ -0,0 +1,107 @@
+package rule
+
+import (
+	"go/ast"
+	"go/token"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// UnnecessaryStmtRule warns on unnecessary statements.
+type UnnecessaryStmtRule struct{}
+
+// Apply applies the rule to given file.
+func (r *UnnecessaryStmtRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+	onFailure := func(failure lint.Failure) {
+		failures = append(failures, failure)
+	}
+
+	w := lintUnnecessaryStmtRule{onFailure}
+	ast.Walk(w, file.AST)
+	return failures
+}
+
+// Name returns the rule name.
+func (r *UnnecessaryStmtRule) Name() string {
+	return "unnecessary-stmt"
+}
+
+type lintUnnecessaryStmtRule struct {
+	onFailure func(lint.Failure)
+}
+
+func (w lintUnnecessaryStmtRule) Visit(node ast.Node) ast.Visitor {
+	switch n := node.(type) {
+	case *ast.FuncDecl:
+		if n.Body == nil || n.Type.Results != nil {
+			return w
+		}
+		stmts := n.Body.List
+		if len(stmts) == 0 {
+			return w
+		}
+
+		lastStmt := stmts[len(stmts)-1]
+		rs, ok := lastStmt.(*ast.ReturnStmt)
+		if !ok {
+			return w
+		}
+
+		if len(rs.Results) == 0 {
+			w.newFailure(lastStmt, "omit unnecessary return statement")
+		}
+
+	case *ast.SwitchStmt:
+		w.checkSwitchBody(n.Body)
+	case *ast.TypeSwitchStmt:
+		w.checkSwitchBody(n.Body)
+	case *ast.CaseClause:
+		if n.Body == nil {
+			return w
+		}
+		stmts := n.Body
+		if len(stmts) == 0 {
+			return w
+		}
+
+		lastStmt := stmts[len(stmts)-1]
+		rs, ok := lastStmt.(*ast.BranchStmt)
+		if !ok {
+			return w
+		}
+
+		if rs.Tok == token.BREAK && rs.Label == nil {
+			w.newFailure(lastStmt, "omit unnecessary break at the end of case clause")
+		}
+	}
+
+	return w
+}
+
+func (w lintUnnecessaryStmtRule) checkSwitchBody(b *ast.BlockStmt) {
+	cases := b.List
+	if len(cases) != 1 {
+		return
+	}
+
+	cc, ok := cases[0].(*ast.CaseClause)
+	if !ok {
+		return
+	}
+
+	if len(cc.List) > 1 { // skip cases with multiple expressions
+		return
+	}
+
+	w.newFailure(b, "switch with only one case can be replaced by an if-then")
+}
+
+func (w lintUnnecessaryStmtRule) newFailure(node ast.Node, msg string) {
+	w.onFailure(lint.Failure{
+		Confidence: 1,
+		Node:       node,
+		Category:   "style",
+		Failure:    msg,
+	})
+}

vendor/github.com/mgechev/revive/rule/unreachable-code.go

@@ -0,0 +1,114 @@
+package rule
+
+import (
+	"go/ast"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// UnreachableCodeRule lints unreachable code.
+type UnreachableCodeRule struct{}
+
+// Apply applies the rule to given file.
+func (r *UnreachableCodeRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+	onFailure := func(failure lint.Failure) {
+		failures = append(failures, failure)
+	}
+
+	var branchingFunctions = map[string]map[string]bool{
+		"os": map[string]bool{"Exit": true},
+		"log": map[string]bool{
+			"Fatal":   true,
+			"Fatalf":  true,
+			"Fatalln": true,
+			"Panic":   true,
+			"Panicf":  true,
+			"Panicln": true,
+		},
+	}
+
+	w := lintUnreachableCode{onFailure, branchingFunctions}
+	ast.Walk(w, file.AST)
+	return failures
+}
+
+// Name returns the rule name.
+func (r *UnreachableCodeRule) Name() string {
+	return "unreachable-code"
+}
+
+type lintUnreachableCode struct {
+	onFailure          func(lint.Failure)
+	branchingFunctions map[string]map[string]bool
+}
+
+func (w lintUnreachableCode) Visit(node ast.Node) ast.Visitor {
+	blk, ok := node.(*ast.BlockStmt)
+	if !ok {
+		return w
+	}
+
+	if len(blk.List) < 2 {
+		return w
+	}
+loop:
+	for i, stmt := range blk.List[:len(blk.List)-1] {
+		// println("iterating ", len(blk.List))
+		next := blk.List[i+1]
+		if _, ok := next.(*ast.LabeledStmt); ok {
+			continue // skip if next statement is labeled
+		}
+
+		switch s := stmt.(type) {
+		case *ast.ReturnStmt:
+			w.onFailure(newUnreachableCodeFailure(s))
+			break loop
+		case *ast.BranchStmt:
+			token := s.Tok.String()
+			if token != "fallthrough" {
+				w.onFailure(newUnreachableCodeFailure(s))
+				break loop
+			}
+		case *ast.ExprStmt:
+			ce, ok := s.X.(*ast.CallExpr)
+			if !ok {
+				continue
+			}
+			// it's a function call
+			fc, ok := ce.Fun.(*ast.SelectorExpr)
+			if !ok {
+				continue
+			}
+
+			id, ok := fc.X.(*ast.Ident)
+
+			if !ok {
+				continue
+			}
+			fn := fc.Sel.Name
+			pkg := id.Name
+			if !w.branchingFunctions[pkg][fn] { // it isn't a call to a branching function
+				continue
+			}
+
+			if _, ok := next.(*ast.ReturnStmt); ok { // return statement needed to satisfy function signature
+				continue
+			}
+
+			w.onFailure(newUnreachableCodeFailure(s))
+			break loop
+		}
+	}
+
+	return w
+}
+
+func newUnreachableCodeFailure(node ast.Node) lint.Failure {
+	return lint.Failure{
+		Confidence: 1,
+		Node:       node,
+		Category:   "logic",
+		Failure:    "unreachable code after this statement",
+	}
+}

vendor/github.com/mgechev/revive/rule/unused-param.go

@@ -0,0 +1,102 @@
+package rule
+
+import (
+	"fmt"
+	"go/ast"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// UnusedParamRule lints unused params in functions.
+type UnusedParamRule struct{}
+
+// Apply applies the rule to given file.
+func (r *UnusedParamRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	onFailure := func(failure lint.Failure) {
+		failures = append(failures, failure)
+	}
+
+	w := lintUnusedParamRule{onFailure: onFailure}
+
+	ast.Walk(w, file.AST)
+
+	return failures
+}
+
+// Name returns the rule name.
+func (r *UnusedParamRule) Name() string {
+	return "unused-parameter"
+}
+
+type lintUnusedParamRule struct {
+	onFailure func(lint.Failure)
+}
+
+func (w lintUnusedParamRule) Visit(node ast.Node) ast.Visitor {
+	switch n := node.(type) {
+	case *ast.FuncDecl:
+		params := retrieveNamedParams(n.Type.Params)
+		if len(params) < 1 {
+			return nil // skip, func without parameters
+		}
+
+		if n.Body == nil {
+			return nil // skip, is a function prototype
+		}
+
+		// inspect the func body looking for references to parameters
+		fselect := func(n ast.Node) bool {
+			ident, isAnID := n.(*ast.Ident)
+
+			if !isAnID {
+				return false
+			}
+
+			_, isAParam := params[ident.Obj]
+			if isAParam {
+				params[ident.Obj] = false // mark as used
+			}
+
+			return false
+		}
+		_ = pick(n.Body, fselect, nil)
+
+		for _, p := range n.Type.Params.List {
+			for _, n := range p.Names {
+				if params[n.Obj] {
+					w.onFailure(lint.Failure{
+						Confidence: 1,
+						Node:       n,
+						Category:   "bad practice",
+						Failure:    fmt.Sprintf("parameter '%s' seems to be unused, consider removing or renaming it as _", n.Name),
+					})
+				}
+			}
+		}
+
+		return nil // full method body already inspected
+	}
+
+	return w
+}
+
+func retrieveNamedParams(params *ast.FieldList) map[*ast.Object]bool {
+	result := map[*ast.Object]bool{}
+	if params.List == nil {
+		return result
+	}
+
+	for _, p := range params.List {
+		for _, n := range p.Names {
+			if n.Name == "_" {
+				continue
+			}
+
+			result[n.Obj] = true
+		}
+	}
+
+	return result
+}

vendor/github.com/mgechev/revive/rule/unused-receiver.go

@@ -0,0 +1,77 @@
+package rule
+
+import (
+	"fmt"
+	"go/ast"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// UnusedReceiverRule lints unused params in functions.
+type UnusedReceiverRule struct{}
+
+// Apply applies the rule to given file.
+func (_ *UnusedReceiverRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	onFailure := func(failure lint.Failure) {
+		failures = append(failures, failure)
+	}
+
+	w := lintUnusedReceiverRule{onFailure: onFailure}
+
+	ast.Walk(w, file.AST)
+
+	return failures
+}
+
+// Name returns the rule name.
+func (_ *UnusedReceiverRule) Name() string {
+	return "unused-receiver"
+}
+
+type lintUnusedReceiverRule struct {
+	onFailure func(lint.Failure)
+}
+
+func (w lintUnusedReceiverRule) Visit(node ast.Node) ast.Visitor {
+	switch n := node.(type) {
+	case *ast.FuncDecl:
+		if n.Recv == nil {
+			return nil // skip this func decl, not a method
+		}
+
+		rec := n.Recv.List[0] // safe to access only the first (unique) element of the list
+		if len(rec.Names) < 1 {
+			return nil // the receiver is anonymous: func (aType) Foo(...) ...
+		}
+
+		recID := rec.Names[0]
+		if recID.Name == "_" {
+			return nil // the receiver is already named _
+		}
+
+		// inspect the func body looking for references to the receiver id
+		fselect := func(n ast.Node) bool {
+			ident, isAnID := n.(*ast.Ident)
+
+			return isAnID && ident.Obj == recID.Obj
+		}
+		refs2recID := pick(n.Body, fselect, nil)
+
+		if len(refs2recID) > 0 {
+			return nil // the receiver is referenced in the func body
+		}
+
+		w.onFailure(lint.Failure{
+			Confidence: 1,
+			Node:       recID,
+			Category:   "bad practice",
+			Failure:    fmt.Sprintf("method receiver '%s' is not referenced in method's body, consider removing or renaming it as _", recID.Name),
+		})
+
+		return nil // full method body already inspected
+	}
+
+	return w
+}

vendor/github.com/mgechev/revive/rule/utils.go

@@ -0,0 +1,191 @@
+package rule
+
+import (
+	"bytes"
+	"fmt"
+	"go/ast"
+	"go/printer"
+	"go/token"
+	"go/types"
+	"regexp"
+	"strings"
+
+	"github.com/mgechev/revive/lint"
+)
+
+const styleGuideBase = "https://golang.org/wiki/CodeReviewComments"
+
+// isBlank returns whether id is the blank identifier "_".
+// If id == nil, the answer is false.
+func isBlank(id *ast.Ident) bool { return id != nil && id.Name == "_" }
+
+func isTest(f *lint.File) bool {
+	return strings.HasSuffix(f.Name, "_test.go")
+}
+
+var commonMethods = map[string]bool{
+	"Error":     true,
+	"Read":      true,
+	"ServeHTTP": true,
+	"String":    true,
+	"Write":     true,
+}
+
+func receiverType(fn *ast.FuncDecl) string {
+	switch e := fn.Recv.List[0].Type.(type) {
+	case *ast.Ident:
+		return e.Name
+	case *ast.StarExpr:
+		if id, ok := e.X.(*ast.Ident); ok {
+			return id.Name
+		}
+	}
+	// The parser accepts much more than just the legal forms.
+	return "invalid-type"
+}
+
+var knownNameExceptions = map[string]bool{
+	"LastInsertId": true, // must match database/sql
+	"kWh":          true,
+}
+
+func isCgoExported(f *ast.FuncDecl) bool {
+	if f.Recv != nil || f.Doc == nil {
+		return false
+	}
+
+	cgoExport := regexp.MustCompile(fmt.Sprintf("(?m)^//export %s$", regexp.QuoteMeta(f.Name.Name)))
+	for _, c := range f.Doc.List {
+		if cgoExport.MatchString(c.Text) {
+			return true
+		}
+	}
+	return false
+}
+
+var allCapsRE = regexp.MustCompile(`^[A-Z0-9_]+$`)
+
+func isIdent(expr ast.Expr, ident string) bool {
+	id, ok := expr.(*ast.Ident)
+	return ok && id.Name == ident
+}
+
+var zeroLiteral = map[string]bool{
+	"false": true, // bool
+	// runes
+	`'\x00'`: true,
+	`'\000'`: true,
+	// strings
+	`""`: true,
+	"``": true,
+	// numerics
+	"0":   true,
+	"0.":  true,
+	"0.0": true,
+	"0i":  true,
+}
+
+func validType(T types.Type) bool {
+	return T != nil &&
+		T != types.Typ[types.Invalid] &&
+		!strings.Contains(T.String(), "invalid type") // good but not foolproof
+}
+
+func isPkgDot(expr ast.Expr, pkg, name string) bool {
+	sel, ok := expr.(*ast.SelectorExpr)
+	return ok && isIdent(sel.X, pkg) && isIdent(sel.Sel, name)
+}
+
+func srcLine(src []byte, p token.Position) string {
+	// Run to end of line in both directions if not at line start/end.
+	lo, hi := p.Offset, p.Offset+1
+	for lo > 0 && src[lo-1] != '\n' {
+		lo--
+	}
+	for hi < len(src) && src[hi-1] != '\n' {
+		hi++
+	}
+	return string(src[lo:hi])
+}
+
+// pick yields a list of nodes by picking them from a sub-ast with root node n.
+// Nodes are selected by applying the fselect function
+// f function is applied to each selected node before inseting it in the final result.
+// If f==nil then it defaults to the identity function (ie it returns the node itself)
+func pick(n ast.Node, fselect func(n ast.Node) bool, f func(n ast.Node) []ast.Node) []ast.Node {
+	var result []ast.Node
+
+	if n == nil {
+		return result
+	}
+
+	if f == nil {
+		f = func(n ast.Node) []ast.Node { return []ast.Node{n} }
+	}
+
+	onSelect := func(n ast.Node) {
+		result = append(result, f(n)...)
+	}
+	p := picker{fselect: fselect, onSelect: onSelect}
+	ast.Walk(p, n)
+	return result
+}
+
+func pickFromExpList(l []ast.Expr, fselect func(n ast.Node) bool, f func(n ast.Node) []ast.Node) []ast.Node {
+	result := make([]ast.Node, 0)
+	for _, e := range l {
+		result = append(result, pick(e, fselect, f)...)
+	}
+	return result
+}
+
+type picker struct {
+	fselect  func(n ast.Node) bool
+	onSelect func(n ast.Node)
+}
+
+func (p picker) Visit(node ast.Node) ast.Visitor {
+	if p.fselect == nil {
+		return nil
+	}
+
+	if p.fselect(node) {
+		p.onSelect(node)
+	}
+
+	return p
+}
+
+// isBoolOp returns true if the given token corresponds to
+// a bool operator
+func isBoolOp(t token.Token) bool {
+	switch t {
+	case token.LAND, token.LOR, token.EQL, token.NEQ:
+		return true
+	}
+
+	return false
+}
+
+const (
+	trueName  = "true"
+	falseName = "false"
+)
+
+func isExprABooleanLit(n ast.Node) (lexeme string, ok bool) {
+	oper, ok := n.(*ast.Ident)
+
+	if !ok {
+		return "", false
+	}
+
+	return oper.Name, (oper.Name == trueName || oper.Name == falseName)
+}
+
+// gofmt returns a string representation of the expression.
+func gofmt(x ast.Expr) string {
+	buf := bytes.Buffer{}
+	fs := token.NewFileSet()
+	printer.Fprint(&buf, fs, x)
+	return buf.String()
+}

vendor/github.com/mgechev/revive/rule/var-declarations.go

@@ -0,0 +1,120 @@
+package rule
+
+import (
+	"fmt"
+	"go/ast"
+	"go/token"
+	"go/types"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// VarDeclarationsRule lints given else constructs.
+type VarDeclarationsRule struct{}
+
+// Apply applies the rule to given file.
+func (r *VarDeclarationsRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	fileAst := file.AST
+	walker := &lintVarDeclarations{
+		file:    file,
+		fileAst: fileAst,
+		onFailure: func(failure lint.Failure) {
+			failures = append(failures, failure)
+		},
+	}
+
+	file.Pkg.TypeCheck()
+	ast.Walk(walker, fileAst)
+
+	return failures
+}
+
+// Name returns the rule name.
+func (r *VarDeclarationsRule) Name() string {
+	return "var-declaration"
+}
+
+type lintVarDeclarations struct {
+	fileAst   *ast.File
+	file      *lint.File
+	lastGen   *ast.GenDecl
+	onFailure func(lint.Failure)
+}
+
+func (w *lintVarDeclarations) Visit(node ast.Node) ast.Visitor {
+	switch v := node.(type) {
+	case *ast.GenDecl:
+		if v.Tok != token.CONST && v.Tok != token.VAR {
+			return nil
+		}
+		w.lastGen = v
+		return w
+	case *ast.ValueSpec:
+		if w.lastGen.Tok == token.CONST {
+			return nil
+		}
+		if len(v.Names) > 1 || v.Type == nil || len(v.Values) == 0 {
+			return nil
+		}
+		rhs := v.Values[0]
+		// An underscore var appears in a common idiom for compile-time interface satisfaction,
+		// as in "var _ Interface = (*Concrete)(nil)".
+		if isIdent(v.Names[0], "_") {
+			return nil
+		}
+		// If the RHS is a zero value, suggest dropping it.
+		zero := false
+		if lit, ok := rhs.(*ast.BasicLit); ok {
+			zero = zeroLiteral[lit.Value]
+		} else if isIdent(rhs, "nil") {
+			zero = true
+		}
+		if zero {
+			w.onFailure(lint.Failure{
+				Confidence: 0.9,
+				Node:       rhs,
+				Category:   "zero-value",
+				Failure:    fmt.Sprintf("should drop = %s from declaration of var %s; it is the zero value", w.file.Render(rhs), v.Names[0]),
+			})
+			return nil
+		}
+		lhsTyp := w.file.Pkg.TypeOf(v.Type)
+		rhsTyp := w.file.Pkg.TypeOf(rhs)
+
+		if !validType(lhsTyp) || !validType(rhsTyp) {
+			// Type checking failed (often due to missing imports).
+			return nil
+		}
+
+		if !types.Identical(lhsTyp, rhsTyp) {
+			// Assignment to a different type is not redundant.
+			return nil
+		}
+
+		// The next three conditions are for suppressing the warning in situations
+		// where we were unable to typecheck.
+
+		// If the LHS type is an interface, don't warn, since it is probably a
+		// concrete type on the RHS. Note that our feeble lexical check here
+		// will only pick up interface{} and other literal interface types;
+		// that covers most of the cases we care to exclude right now.
+		if _, ok := v.Type.(*ast.InterfaceType); ok {
+			return nil
+		}
+		// If the RHS is an untyped const, only warn if the LHS type is its default type.
+		if defType, ok := w.file.IsUntypedConst(rhs); ok && !isIdent(v.Type, defType) {
+			return nil
+		}
+
+		w.onFailure(lint.Failure{
+			Category:   "type-inference",
+			Confidence: 0.8,
+			Node:       v.Type,
+			Failure:    fmt.Sprintf("should omit type %s from declaration of var %s; it will be inferred from the right-hand side", w.file.Render(v.Type), v.Names[0]),
+		})
+		return nil
+	}
+	return w
+}

vendor/github.com/mgechev/revive/rule/var-naming.go

@@ -0,0 +1,230 @@
+package rule
+
+import (
+	"fmt"
+	"go/ast"
+	"go/token"
+	"strings"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// VarNamingRule lints given else constructs.
+type VarNamingRule struct{}
+
+// Apply applies the rule to given file.
+func (r *VarNamingRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	var whitelist []string
+	var blacklist []string
+
+	if len(arguments) >= 1 {
+		whitelist = getList(arguments[0], "whitelist")
+	}
+
+	if len(arguments) >= 2 {
+		blacklist = getList(arguments[1], "blacklist")
+	}
+
+	fileAst := file.AST
+	walker := lintNames{
+		file:      file,
+		fileAst:   fileAst,
+		whitelist: whitelist,
+		blacklist: blacklist,
+		onFailure: func(failure lint.Failure) {
+			failures = append(failures, failure)
+		},
+	}
+
+	// Package names need slightly different handling than other names.
+	if strings.Contains(walker.fileAst.Name.Name, "_") && !strings.HasSuffix(walker.fileAst.Name.Name, "_test") {
+		walker.onFailure(lint.Failure{
+			Failure:    "don't use an underscore in package name",
+			Confidence: 1,
+			Node:       walker.fileAst,
+			Category:   "naming",
+		})
+	}
+
+	ast.Walk(&walker, fileAst)
+
+	return failures
+}
+
+// Name returns the rule name.
+func (r *VarNamingRule) Name() string {
+	return "var-naming"
+}
+
+func checkList(fl *ast.FieldList, thing string, w *lintNames) {
+	if fl == nil {
+		return
+	}
+	for _, f := range fl.List {
+		for _, id := range f.Names {
+			check(id, thing, w)
+		}
+	}
+}
+
+func check(id *ast.Ident, thing string, w *lintNames) {
+	if id.Name == "_" {
+		return
+	}
+	if knownNameExceptions[id.Name] {
+		return
+	}
+
+	// Handle two common styles from other languages that don't belong in Go.
+	if len(id.Name) >= 5 && allCapsRE.MatchString(id.Name) && strings.Contains(id.Name, "_") {
+		w.onFailure(lint.Failure{
+			Failure:    "don't use ALL_CAPS in Go names; use CamelCase",
+			Confidence: 0.8,
+			Node:       id,
+			Category:   "naming",
+		})
+		return
+	}
+	if len(id.Name) > 2 && id.Name[0] == 'k' && id.Name[1] >= 'A' && id.Name[1] <= 'Z' {
+		should := string(id.Name[1]+'a'-'A') + id.Name[2:]
+		w.onFailure(lint.Failure{
+			Failure:    fmt.Sprintf("don't use leading k in Go names; %s %s should be %s", thing, id.Name, should),
+			Confidence: 0.8,
+			Node:       id,
+			Category:   "naming",
+		})
+	}
+
+	should := lint.Name(id.Name, w.whitelist, w.blacklist)
+	if id.Name == should {
+		return
+	}
+
+	if len(id.Name) > 2 && strings.Contains(id.Name[1:], "_") {
+		w.onFailure(lint.Failure{
+			Failure:    fmt.Sprintf("don't use underscores in Go names; %s %s should be %s", thing, id.Name, should),
+			Confidence: 0.9,
+			Node:       id,
+			Category:   "naming",
+		})
+		return
+	}
+	w.onFailure(lint.Failure{
+		Failure:    fmt.Sprintf("%s %s should be %s", thing, id.Name, should),
+		Confidence: 0.8,
+		Node:       id,
+		Category:   "naming",
+	})
+}
+
+type lintNames struct {
+	file                   *lint.File
+	fileAst                *ast.File
+	lastGen                *ast.GenDecl
+	genDeclMissingComments map[*ast.GenDecl]bool
+	onFailure              func(lint.Failure)
+	whitelist              []string
+	blacklist              []string
+}
+
+func (w *lintNames) Visit(n ast.Node) ast.Visitor {
+	switch v := n.(type) {
+	case *ast.AssignStmt:
+		if v.Tok == token.ASSIGN {
+			return w
+		}
+		for _, exp := range v.Lhs {
+			if id, ok := exp.(*ast.Ident); ok {
+				check(id, "var", w)
+			}
+		}
+	case *ast.FuncDecl:
+		if w.file.IsTest() && (strings.HasPrefix(v.Name.Name, "Example") || strings.HasPrefix(v.Name.Name, "Test") || strings.HasPrefix(v.Name.Name, "Benchmark")) {
+			return w
+		}
+
+		thing := "func"
+		if v.Recv != nil {
+			thing = "method"
+		}
+
+		// Exclude naming warnings for functions that are exported to C but
+		// not exported in the Go API.
+		// See https://github.com/golang/lint/issues/144.
+		if ast.IsExported(v.Name.Name) || !isCgoExported(v) {
+			check(v.Name, thing, w)
+		}
+
+		checkList(v.Type.Params, thing+" parameter", w)
+		checkList(v.Type.Results, thing+" result", w)
+	case *ast.GenDecl:
+		if v.Tok == token.IMPORT {
+			return w
+		}
+		var thing string
+		switch v.Tok {
+		case token.CONST:
+			thing = "const"
+		case token.TYPE:
+			thing = "type"
+		case token.VAR:
+			thing = "var"
+		}
+		for _, spec := range v.Specs {
+			switch s := spec.(type) {
+			case *ast.TypeSpec:
+				check(s.Name, thing, w)
+			case *ast.ValueSpec:
+				for _, id := range s.Names {
+					check(id, thing, w)
+				}
+			}
+		}
+	case *ast.InterfaceType:
+		// Do not check interface method names.
+		// They are often constrainted by the method names of concrete types.
+		for _, x := range v.Methods.List {
+			ft, ok := x.Type.(*ast.FuncType)
+			if !ok { // might be an embedded interface name
+				continue
+			}
+			checkList(ft.Params, "interface method parameter", w)
+			checkList(ft.Results, "interface method result", w)
+		}
+	case *ast.RangeStmt:
+		if v.Tok == token.ASSIGN {
+			return w
+		}
+		if id, ok := v.Key.(*ast.Ident); ok {
+			check(id, "range var", w)
+		}
+		if id, ok := v.Value.(*ast.Ident); ok {
+			check(id, "range var", w)
+		}
+	case *ast.StructType:
+		for _, f := range v.Fields.List {
+			for _, id := range f.Names {
+				check(id, "struct field", w)
+			}
+		}
+	}
+	return w
+}
+
+func getList(arg interface{}, argName string) []string {
+	temp, ok := arg.([]interface{})
+	if !ok {
+		panic(fmt.Sprintf("Invalid argument to the var-naming rule. Expecting a %s of type slice with initialisms, got %T", argName, arg))
+	}
+	var list []string
+	for _, v := range temp {
+		if val, ok := v.(string); ok {
+			list = append(list, val)
+		} else {
+			panic(fmt.Sprintf("Invalid %s values of the var-naming rule. Expecting slice of strings but got element of type %T", val, arg))
+		}
+	}
+	return list
+}

vendor/github.com/mgechev/revive/rule/waitgroup-by-value.go

@@ -0,0 +1,66 @@
+package rule
+
+import (
+	"go/ast"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// WaitGroupByValueRule lints sync.WaitGroup passed by copy in functions.
+type WaitGroupByValueRule struct{}
+
+// Apply applies the rule to given file.
+func (r *WaitGroupByValueRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	onFailure := func(failure lint.Failure) {
+		failures = append(failures, failure)
+	}
+
+	w := lintWaitGroupByValueRule{onFailure: onFailure}
+	ast.Walk(w, file.AST)
+	return failures
+}
+
+// Name returns the rule name.
+func (r *WaitGroupByValueRule) Name() string {
+	return "waitgroup-by-value"
+}
+
+type lintWaitGroupByValueRule struct {
+	onFailure func(lint.Failure)
+}
+
+func (w lintWaitGroupByValueRule) Visit(node ast.Node) ast.Visitor {
+	// look for function declarations
+	fd, ok := node.(*ast.FuncDecl)
+	if !ok {
+		return w
+	}
+
+	// Check all function's parameters
+	for _, field := range fd.Type.Params.List {
+		if !w.isWaitGroup(field.Type) {
+			continue
+		}
+
+		w.onFailure(lint.Failure{
+			Confidence: 1,
+			Node:       field,
+			Failure:    "sync.WaitGroup passed by value, the function will get a copy of the original one",
+		})
+	}
+
+	return nil
+}
+
+func (lintWaitGroupByValueRule) isWaitGroup(ft ast.Expr) bool {
+	se, ok := ft.(*ast.SelectorExpr)
+	if !ok {
+		return false
+	}
+
+	x, _ := se.X.(*ast.Ident)
+	sel := se.Sel.Name
+	return x.Name == "sync" && sel == "WaitGroup"
+}