Serve .patch for pull requests (#3305)

* Serve .patch for pull requests

Closes #3259
Updates "git" module, for GetFormatPatch

* Handle io.Copy error

vendor/code.gitea.io/git/MAINTAINERS

@@ -7,6 +7,7 @@ Kim Carlbäcker <kim.carlbacker@gmail.com> (@bkcsoft)
 LefsFlare <nobody@nobody.tld> (@LefsFlarey)
 Lunny Xiao <xiaolunwen@gmail.com> (@lunny)
 Matthias Loibl <mail@matthiasloibl.com> (@metalmatze)
+Morgan Bazalgette <the@howl.moe> (@thehowl)
 Rachid Zarouali <nobody@nobody.tld> (@xinity)
 Rémy Boulanouar <admin@dblk.org> (@DblK)
 Sandro Santilli <strk@kbt.io> (@strk)

vendor/code.gitea.io/git/command.go

@@ -17,6 +17,9 @@ import (
 var (
 	// GlobalCommandArgs global command args for external package setting
 	GlobalCommandArgs []string
+
+	// DefaultCommandExecutionTimeout default command execution timeout duration
+	DefaultCommandExecutionTimeout = 60 * time.Second
 )
 
 // Command represents a command with its subcommands or arguments.
@@ -50,7 +53,7 @@ func (c *Command) AddArguments(args ...string) *Command {
 // it pipes stdout and stderr to given io.Writer.
 func (c *Command) RunInDirTimeoutPipeline(timeout time.Duration, dir string, stdout, stderr io.Writer) error {
 	if timeout == -1 {
-		timeout = 60 * time.Second
+		timeout = DefaultCommandExecutionTimeout
 	}
 
 	if len(dir) == 0 {

vendor/code.gitea.io/git/repo_pull.go

@@ -5,8 +5,10 @@
 package git
 
 import (
+	"bytes"
 	"container/list"
 	"fmt"
+	"io"
 	"strconv"
 	"strings"
 	"time"
@@ -73,3 +75,15 @@ func (repo *Repository) GetPullRequestInfo(basePath, baseBranch, headBranch stri
 func (repo *Repository) GetPatch(base, head string) ([]byte, error) {
 	return NewCommand("diff", "-p", "--binary", base, head).RunInDirBytes(repo.Path)
 }
+
+// GetFormatPatch generates and returns format-patch data between given revisions.
+func (repo *Repository) GetFormatPatch(base, head string) (io.Reader, error) {
+	stdout := new(bytes.Buffer)
+	stderr := new(bytes.Buffer)
+
+	if err := NewCommand("format-patch", "--binary", "--stdout", base+"..."+head).
+		RunInDirPipeline(repo.Path, stdout, stderr); err != nil {
+		return nil, concatenateError(err, stderr.String())
+	}
+	return stdout, nil
+}