Update to go-git v5.1.0 (#11936)

Signed-off-by: Andrew Thornton <art27@cantab.net>

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

vendor/github.com/imdario/mergo/mergo.go

@@ -0,0 +1,97 @@
+// Copyright 2013 Dario Castañé. All rights reserved.
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Based on src/pkg/reflect/deepequal.go from official
+// golang's stdlib.
+
+package mergo
+
+import (
+	"errors"
+	"reflect"
+)
+
+// Errors reported by Mergo when it finds invalid arguments.
+var (
+	ErrNilArguments                = errors.New("src and dst must not be nil")
+	ErrDifferentArgumentsTypes     = errors.New("src and dst must be of same type")
+	ErrNotSupported                = errors.New("only structs and maps are supported")
+	ErrExpectedMapAsDestination    = errors.New("dst was expected to be a map")
+	ErrExpectedStructAsDestination = errors.New("dst was expected to be a struct")
+)
+
+// During deepMerge, must keep track of checks that are
+// in progress.  The comparison algorithm assumes that all
+// checks in progress are true when it reencounters them.
+// Visited are stored in a map indexed by 17 * a1 + a2;
+type visit struct {
+	ptr  uintptr
+	typ  reflect.Type
+	next *visit
+}
+
+// From src/pkg/encoding/json/encode.go.
+func isEmptyValue(v reflect.Value) bool {
+	switch v.Kind() {
+	case reflect.Array, reflect.Map, reflect.Slice, reflect.String:
+		return v.Len() == 0
+	case reflect.Bool:
+		return !v.Bool()
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return v.Int() == 0
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		return v.Uint() == 0
+	case reflect.Float32, reflect.Float64:
+		return v.Float() == 0
+	case reflect.Interface, reflect.Ptr:
+		if v.IsNil() {
+			return true
+		}
+		return isEmptyValue(v.Elem())
+	case reflect.Func:
+		return v.IsNil()
+	case reflect.Invalid:
+		return true
+	}
+	return false
+}
+
+func resolveValues(dst, src interface{}) (vDst, vSrc reflect.Value, err error) {
+	if dst == nil || src == nil {
+		err = ErrNilArguments
+		return
+	}
+	vDst = reflect.ValueOf(dst).Elem()
+	if vDst.Kind() != reflect.Struct && vDst.Kind() != reflect.Map {
+		err = ErrNotSupported
+		return
+	}
+	vSrc = reflect.ValueOf(src)
+	// We check if vSrc is a pointer to dereference it.
+	if vSrc.Kind() == reflect.Ptr {
+		vSrc = vSrc.Elem()
+	}
+	return
+}
+
+// Traverses recursively both values, assigning src's fields values to dst.
+// The map argument tracks comparisons that have already been seen, which allows
+// short circuiting on recursive types.
+func deeper(dst, src reflect.Value, visited map[uintptr]*visit, depth int) (err error) {
+	if dst.CanAddr() {
+		addr := dst.UnsafeAddr()
+		h := 17 * addr
+		seen := visited[h]
+		typ := dst.Type()
+		for p := seen; p != nil; p = p.next {
+			if p.ptr == addr && p.typ == typ {
+				return nil
+			}
+		}
+		// Remember, remember...
+		visited[h] = &visit{addr, typ, seen}
+	}
+	return // TODO refactor
+}