Refactor git command stdio pipe (#36422)

Most potential deadlock problems should have been fixed, and new code is
unlikely to cause new problems with the new design.

Also raise the minimum Git version required to 2.6.0 (released in 2015)

services/repository/branch.go

@@ -264,12 +264,12 @@ func checkBranchName(ctx context.Context, repo *repo_model.Repository, name stri
 			return git_model.ErrBranchAlreadyExists{
 				BranchName: name,
 			}
-		// If branchRefName like a/b but we want to create a branch named a then we have a conflict
+		// If branchRefName like "a/b" but we want to create a branch named a then we have a conflict
 		case strings.HasPrefix(branchRefName, name+"/"):
 			return git_model.ErrBranchNameConflict{
 				BranchName: branchRefName,
 			}
-			// Conversely if branchRefName like a but we want to create a branch named a/b then we also have a conflict
+			// Conversely if branchRefName like "a" but we want to create a branch named "a/b" then we also have a conflict
 		case strings.HasPrefix(name, branchRefName+"/"):
 			return git_model.ErrBranchNameConflict{
 				BranchName: branchRefName,
@@ -281,7 +281,6 @@ func checkBranchName(ctx context.Context, repo *repo_model.Repository, name stri
 		}
 		return nil
 	})
-
 	return err
 }
 

services/repository/contributors_graph.go

@@ -8,7 +8,6 @@ import (
 	"context"
 	"errors"
 	"fmt"
-	"io"
 	"strconv"
 	"strings"
 	"sync"
@@ -122,10 +121,11 @@ func getExtendedCommitStats(repo *git.Repository, revision string /*, limit int
 	// AddOptionFormat("--max-count=%d", limit)
 	gitCmd.AddDynamicArguments(baseCommit.ID.String())
 
-	var stdoutReader io.ReadCloser
+	stdoutReader, stdoutReaderClose := gitCmd.MakeStdoutPipe()
+	defer stdoutReaderClose()
+
 	var extendedCommitStats []*ExtendedCommitStats
 	err = gitCmd.WithDir(repo.Path).
-		WithStdoutReader(&stdoutReader).
 		WithPipelineFunc(func(ctx gitcmd.Context) error {
 			scanner := bufio.NewScanner(stdoutReader)
 

services/repository/files/patch.go

@@ -170,7 +170,7 @@ func ApplyDiffPatch(ctx context.Context, repo *repo_model.Repository, doer *user
 	}
 
 	if err := cmdApply.WithDir(t.basePath).
-		WithStdin(strings.NewReader(opts.Content)).
+		WithStdinBytes([]byte(opts.Content)).
 		RunWithStderr(ctx); err != nil {
 		return nil, fmt.Errorf("git apply error: %w", err)
 	}

services/repository/files/temp_repo.go

@@ -117,7 +117,7 @@ func (t *TemporaryUploadRepository) LsFiles(ctx context.Context, filenames ...st
 	stdOut := new(bytes.Buffer)
 	if err := gitcmd.NewCommand("ls-files", "-z").AddDashesAndList(filenames...).
 		WithDir(t.basePath).
-		WithStdout(stdOut).
+		WithStdoutBuffer(stdOut).
 		RunWithStderr(ctx); err != nil {
 		return nil, fmt.Errorf("unable to run git ls-files for temporary repo of: %s, error: %w", t.repo.FullName(), err)
 	}
@@ -155,7 +155,7 @@ func (t *TemporaryUploadRepository) RemoveFilesFromIndex(ctx context.Context, fi
 
 	if err := gitcmd.NewCommand("update-index", "--remove", "-z", "--index-info").
 		WithDir(t.basePath).
-		WithStdin(stdIn).
+		WithStdinBytes(stdIn.Bytes()).
 		RunWithStderr(ctx); err != nil {
 		return fmt.Errorf("unable to update-index for temporary repo: %q, error: %w", t.repo.FullName(), err)
 	}
@@ -167,8 +167,8 @@ func (t *TemporaryUploadRepository) HashObjectAndWrite(ctx context.Context, cont
 	stdOut := new(bytes.Buffer)
 	if err := gitcmd.NewCommand("hash-object", "-w", "--stdin").
 		WithDir(t.basePath).
-		WithStdout(stdOut).
-		WithStdin(content).
+		WithStdoutBuffer(stdOut).
+		WithStdinCopy(content).
 		RunWithStderr(ctx); err != nil {
 		return "", fmt.Errorf("unable to hash-object to temporary repo: %s, error: %w", t.repo.FullName(), err)
 	}
@@ -330,8 +330,8 @@ func (t *TemporaryUploadRepository) CommitTree(ctx context.Context, opts *Commit
 	if err := cmdCommitTree.
 		WithEnv(env).
 		WithDir(t.basePath).
-		WithStdout(stdout).
-		WithStdin(messageBytes).
+		WithStdoutBuffer(stdout).
+		WithStdinBytes(messageBytes.Bytes()).
 		RunWithStderr(ctx); err != nil {
 		return "", fmt.Errorf("unable to commit-tree in temporary repo: %s Error: %w", t.repo.FullName(), err)
 	}
@@ -363,11 +363,12 @@ func (t *TemporaryUploadRepository) Push(ctx context.Context, doer *user_model.U
 // DiffIndex returns a Diff of the current index to the head
 func (t *TemporaryUploadRepository) DiffIndex(ctx context.Context) (*gitdiff.Diff, error) {
 	var diff *gitdiff.Diff
-	var stdoutReader io.ReadCloser
-	err := gitcmd.NewCommand("diff-index", "--src-prefix=\\a/", "--dst-prefix=\\b/", "--cached", "-p", "HEAD").
-		WithTimeout(30 * time.Second).
+	cmd := gitcmd.NewCommand("diff-index", "--src-prefix=\\a/", "--dst-prefix=\\b/", "--cached", "-p", "HEAD")
+	stdoutReader, stdoutReaderClose := cmd.MakeStdoutPipe()
+	defer stdoutReaderClose()
+
+	err := cmd.WithTimeout(30 * time.Second).
 		WithDir(t.basePath).
-		WithStdoutReader(&stdoutReader).
 		WithPipelineFunc(func(ctx gitcmd.Context) error {
 			var diffErr error
 			diff, diffErr = gitdiff.ParsePatch(ctx, setting.Git.MaxGitDiffLines, setting.Git.MaxGitDiffLineCharacters, setting.Git.MaxGitDiffFiles, stdoutReader, "")

services/repository/gitgraph/graph.go

@@ -6,7 +6,6 @@ package gitgraph
 import (
 	"bufio"
 	"bytes"
-	"io"
 
 	"code.gitea.io/gitea/modules/git"
 	"code.gitea.io/gitea/modules/git/gitcmd"
@@ -45,10 +44,10 @@ func GetCommitGraph(r *git.Repository, page, maxAllowedColors int, hidePRRefs bo
 
 	commitsToSkip := setting.UI.GraphMaxCommitNum * (page - 1)
 
-	var stdoutReader io.ReadCloser
+	stdoutReader, stdoutReaderClose := graphCmd.MakeStdoutPipe()
+	defer stdoutReaderClose()
 	if err := graphCmd.
 		WithDir(r.Path).
-		WithStdoutReader(&stdoutReader).
 		WithPipelineFunc(func(ctx gitcmd.Context) error {
 			scanner := bufio.NewScanner(stdoutReader)
 			parser := &Parser{}