Refactor git command package to improve security and maintainability (#22678)

This PR follows #21535 (and replace #22592)

## Review without space diff

https://github.com/go-gitea/gitea/pull/22678/files?diff=split&w=1

## Purpose of this PR

1. Make git module command completely safe (risky user inputs won't be
passed as argument option anymore)
2. Avoid low-level mistakes like
https://github.com/go-gitea/gitea/pull/22098#discussion_r1045234918
3. Remove deprecated and dirty `CmdArgCheck` function, hide the `CmdArg`
type
4. Simplify code when using git command

## The main idea of this PR

* Move the `git.CmdArg` to the `internal` package, then no other package
except `git` could use it. Then developers could never do
`AddArguments(git.CmdArg(userInput))` any more.
* Introduce `git.ToTrustedCmdArgs`, it's for user-provided and already
trusted arguments. It's only used in a few cases, for example: use git
arguments from config file, help unit test with some arguments.
* Introduce `AddOptionValues` and `AddOptionFormat`, they make code more
clear and simple:
    * Before: `AddArguments("-m").AddDynamicArguments(message)`
    * After: `AddOptionValues("-m", message)`
    * -
* Before: `AddArguments(git.CmdArg(fmt.Sprintf("--author='%s <%s>'",
sig.Name, sig.Email)))`
* After: `AddOptionFormat("--author='%s <%s>'", sig.Name, sig.Email)`

## FAQ

### Why these changes were not done in #21535 ?

#21535 is mainly a search&replace, it did its best to not change too
much logic.

Making the framework better needs a lot of changes, so this separate PR
is needed as the second step.


### The naming of `AddOptionXxx`

According to git's manual, the `--xxx` part is called `option`.

### How can it guarantee that `internal.CmdArg` won't be not misused?

Go's specification guarantees that. Trying to access other package's
internal package causes compilation error.

And, `golangci-lint` also denies the git/internal package. Only the
`git/command.go` can use it carefully.

### There is still a `ToTrustedCmdArgs`, will it still allow developers
to make mistakes and pass untrusted arguments?

Generally speaking, no. Because when using `ToTrustedCmdArgs`, the code
will be very complex (see the changes for examples). Then developers and
reviewers can know that something might be unreasonable.

### Why there was a `CmdArgCheck` and why it's removed?

At the moment of #21535, to reduce unnecessary changes, `CmdArgCheck`
was introduced as a hacky patch. Now, almost all code could be written
as `cmd := NewCommand(); cmd.AddXxx(...)`, then there is no need for
`CmdArgCheck` anymore.


### Why many codes for `signArg == ""` is deleted?

Because in the old code, `signArg` could never be empty string, it's
either `-S[key-id]` or `--no-gpg-sign`. So the `signArg == ""` is just
dead code.

---------

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

13 files changed, 149 insertions, 211 deletions

diff --git a/services/cron/tasks_basic.go b/services/cron/tasks_basic.go
index 05aef6623d..aad0e39591 100644
--- a/services/cron/tasks_basic.go
+++ b/services/cron/tasks_basic.go
@@ -59,11 +59,7 @@ func registerRepoHealthCheck() {
 	}, func(ctx context.Context, _ *user_model.User, config Config) error {
 		rhcConfig := config.(*RepoHealthCheckConfig)
 		// the git args are set by config, they can be safe to be trusted
-		args := make([]git.CmdArg, 0, len(rhcConfig.Args))
-		for _, arg := range rhcConfig.Args {
-			args = append(args, git.CmdArg(arg))
-		}
-		return repo_service.GitFsckRepos(ctx, rhcConfig.Timeout, args)
+		return repo_service.GitFsckRepos(ctx, rhcConfig.Timeout, git.ToTrustedCmdArgs(rhcConfig.Args))
 	})
 }
 
diff --git a/services/cron/tasks_extended.go b/services/cron/tasks_extended.go
index 520d940edf..3e0dbd132e 100644
--- a/services/cron/tasks_extended.go
+++ b/services/cron/tasks_extended.go
@@ -61,11 +61,7 @@ func registerGarbageCollectRepositories() {
 	}, func(ctx context.Context, _ *user_model.User, config Config) error {
 		rhcConfig := config.(*RepoHealthCheckConfig)
 		// the git args are set by config, they can be safe to be trusted
-		args := make([]git.CmdArg, 0, len(rhcConfig.Args))
-		for _, arg := range rhcConfig.Args {
-			args = append(args, git.CmdArg(arg))
-		}
-		return repo_service.GitGcRepos(ctx, rhcConfig.Timeout, args...)
+		return repo_service.GitGcRepos(ctx, rhcConfig.Timeout, git.ToTrustedCmdArgs(rhcConfig.Args))
 	})
 }
 
diff --git a/services/gitdiff/gitdiff.go b/services/gitdiff/gitdiff.go
index d3ee93ec94..4a74c1a894 100644
--- a/services/gitdiff/gitdiff.go
+++ b/services/gitdiff/gitdiff.go
@@ -1056,7 +1056,7 @@ type DiffOptions struct {
 	MaxLines           int
 	MaxLineCharacters  int
 	MaxFiles           int
-	WhitespaceBehavior git.CmdArg
+	WhitespaceBehavior git.TrustedCmdArgs
 	DirectComparison   bool
 }
 
@@ -1071,38 +1071,22 @@ func GetDiff(gitRepo *git.Repository, opts *DiffOptions, files ...string) (*Diff
 		return nil, err
 	}
 
-	argsLength := 6
-	if len(opts.WhitespaceBehavior) > 0 {
-		argsLength++
-	}
-	if len(opts.SkipTo) > 0 {
-		argsLength++
-	}
-	if len(files) > 0 {
-		argsLength += len(files) + 1
-	}
-
-	diffArgs := make([]git.CmdArg, 0, argsLength)
+	cmdDiff := git.NewCommand(gitRepo.Ctx)
 	if (len(opts.BeforeCommitID) == 0 || opts.BeforeCommitID == git.EmptySHA) && commit.ParentCount() == 0 {
-		diffArgs = append(diffArgs, "diff", "--src-prefix=\\a/", "--dst-prefix=\\b/", "-M")
-		if len(opts.WhitespaceBehavior) != 0 {
-			diffArgs = append(diffArgs, opts.WhitespaceBehavior)
-		}
-		// append empty tree ref
-		diffArgs = append(diffArgs, "4b825dc642cb6eb9a060e54bf8d69288fbee4904")
-		diffArgs = append(diffArgs, git.CmdArgCheck(opts.AfterCommitID))
+		cmdDiff.AddArguments("diff", "--src-prefix=\\a/", "--dst-prefix=\\b/", "-M").
+			AddArguments(opts.WhitespaceBehavior...).
+			AddArguments("4b825dc642cb6eb9a060e54bf8d69288fbee4904"). // append empty tree ref
+			AddDynamicArguments(opts.AfterCommitID)
 	} else {
 		actualBeforeCommitID := opts.BeforeCommitID
 		if len(actualBeforeCommitID) == 0 {
 			parentCommit, _ := commit.Parent(0)
 			actualBeforeCommitID = parentCommit.ID.String()
 		}
-		diffArgs = append(diffArgs, "diff", "--src-prefix=\\a/", "--dst-prefix=\\b/", "-M")
-		if len(opts.WhitespaceBehavior) != 0 {
-			diffArgs = append(diffArgs, opts.WhitespaceBehavior)
-		}
-		diffArgs = append(diffArgs, git.CmdArgCheck(actualBeforeCommitID))
-		diffArgs = append(diffArgs, git.CmdArgCheck(opts.AfterCommitID))
+
+		cmdDiff.AddArguments("diff", "--src-prefix=\\a/", "--dst-prefix=\\b/", "-M").
+			AddArguments(opts.WhitespaceBehavior...).
+			AddDynamicArguments(actualBeforeCommitID, opts.AfterCommitID)
 		opts.BeforeCommitID = actualBeforeCommitID
 	}
 
@@ -1111,16 +1095,11 @@ func GetDiff(gitRepo *git.Repository, opts *DiffOptions, files ...string) (*Diff
 	// the skipping for us
 	parsePatchSkipToFile := opts.SkipTo
 	if opts.SkipTo != "" && git.CheckGitVersionAtLeast("2.31") == nil {
-		diffArgs = append(diffArgs, git.CmdArg("--skip-to="+opts.SkipTo))
+		cmdDiff.AddOptionFormat("--skip-to=%s", opts.SkipTo)
 		parsePatchSkipToFile = ""
 	}
 
-	if len(files) > 0 {
-		diffArgs = append(diffArgs, "--")
-		for _, file := range files {
-			diffArgs = append(diffArgs, git.CmdArg(file)) // it's safe to cast it to CmdArg because there is a "--" before
-		}
-	}
+	cmdDiff.AddDashesAndList(files...)
 
 	reader, writer := io.Pipe()
 	defer func() {
@@ -1128,10 +1107,9 @@ func GetDiff(gitRepo *git.Repository, opts *DiffOptions, files ...string) (*Diff
 		_ = writer.Close()
 	}()
 
-	go func(ctx context.Context, diffArgs []git.CmdArg, repoPath string, writer *io.PipeWriter) {
-		cmd := git.NewCommand(ctx, diffArgs...)
-		cmd.SetDescription(fmt.Sprintf("GetDiffRange [repo_path: %s]", repoPath))
-		if err := cmd.Run(&git.RunOpts{
+	go func() {
+		cmdDiff.SetDescription(fmt.Sprintf("GetDiffRange [repo_path: %s]", repoPath))
+		if err := cmdDiff.Run(&git.RunOpts{
 			Timeout: time.Duration(setting.Git.Timeout.Default) * time.Second,
 			Dir:     repoPath,
 			Stderr:  os.Stderr,
@@ -1141,7 +1119,7 @@ func GetDiff(gitRepo *git.Repository, opts *DiffOptions, files ...string) (*Diff
 		}
 
 		_ = writer.Close()
-	}(gitRepo.Ctx, diffArgs, repoPath, writer)
+	}()
 
 	diff, err := ParsePatch(opts.MaxLines, opts.MaxLineCharacters, opts.MaxFiles, reader, parsePatchSkipToFile)
 	if err != nil {
@@ -1201,16 +1179,16 @@ func GetDiff(gitRepo *git.Repository, opts *DiffOptions, files ...string) (*Diff
 		separator = ".."
 	}
 
-	shortstatArgs := []git.CmdArg{git.CmdArgCheck(opts.BeforeCommitID + separator + opts.AfterCommitID)}
+	diffPaths := []string{opts.BeforeCommitID + separator + opts.AfterCommitID}
 	if len(opts.BeforeCommitID) == 0 || opts.BeforeCommitID == git.EmptySHA {
-		shortstatArgs = []git.CmdArg{git.EmptyTreeSHA, git.CmdArgCheck(opts.AfterCommitID)}
+		diffPaths = []string{git.EmptyTreeSHA, opts.AfterCommitID}
 	}
-	diff.NumFiles, diff.TotalAddition, diff.TotalDeletion, err = git.GetDiffShortStat(gitRepo.Ctx, repoPath, shortstatArgs...)
+	diff.NumFiles, diff.TotalAddition, diff.TotalDeletion, err = git.GetDiffShortStat(gitRepo.Ctx, repoPath, nil, diffPaths...)
 	if err != nil && strings.Contains(err.Error(), "no merge base") {
 		// git >= 2.28 now returns an error if base and head have become unrelated.
 		// previously it would return the results of git diff --shortstat base head so let's try that...
-		shortstatArgs = []git.CmdArg{git.CmdArgCheck(opts.BeforeCommitID), git.CmdArgCheck(opts.AfterCommitID)}
-		diff.NumFiles, diff.TotalAddition, diff.TotalDeletion, err = git.GetDiffShortStat(gitRepo.Ctx, repoPath, shortstatArgs...)
+		diffPaths = []string{opts.BeforeCommitID, opts.AfterCommitID}
+		diff.NumFiles, diff.TotalAddition, diff.TotalDeletion, err = git.GetDiffShortStat(gitRepo.Ctx, repoPath, nil, diffPaths...)
 	}
 	if err != nil {
 		return nil, err
@@ -1324,17 +1302,17 @@ func CommentMustAsDiff(c *issues_model.Comment) *Diff {
 }
 
 // GetWhitespaceFlag returns git diff flag for treating whitespaces
-func GetWhitespaceFlag(whitespaceBehavior string) git.CmdArg {
-	whitespaceFlags := map[string]string{
-		"ignore-all":    "-w",
-		"ignore-change": "-b",
-		"ignore-eol":    "--ignore-space-at-eol",
-		"show-all":      "",
+func GetWhitespaceFlag(whitespaceBehavior string) git.TrustedCmdArgs {
+	whitespaceFlags := map[string]git.TrustedCmdArgs{
+		"ignore-all":    {"-w"},
+		"ignore-change": {"-b"},
+		"ignore-eol":    {"--ignore-space-at-eol"},
+		"show-all":      nil,
 	}
 
 	if flag, ok := whitespaceFlags[whitespaceBehavior]; ok {
-		return git.CmdArg(flag)
+		return flag
 	}
 	log.Warn("unknown whitespace behavior: %q, default to 'show-all'", whitespaceBehavior)
-	return ""
+	return nil
 }
diff --git a/services/gitdiff/gitdiff_test.go b/services/gitdiff/gitdiff_test.go
index 267f0e4cff..eb9ed862e8 100644
--- a/services/gitdiff/gitdiff_test.go
+++ b/services/gitdiff/gitdiff_test.go
@@ -626,7 +626,7 @@ func TestGetDiffRangeWithWhitespaceBehavior(t *testing.T) {
 		return
 	}
 	defer gitRepo.Close()
-	for _, behavior := range []git.CmdArg{"-w", "--ignore-space-at-eol", "-b", ""} {
+	for _, behavior := range []git.TrustedCmdArgs{{"-w"}, {"--ignore-space-at-eol"}, {"-b"}, nil} {
 		diffs, err := GetDiff(gitRepo,
 			&DiffOptions{
 				AfterCommitID:      "bd7063cc7c04689c4d082183d32a604ed27a24f9",
diff --git a/services/mirror/mirror_pull.go b/services/mirror/mirror_pull.go
index 98e8d122a5..7dee90352e 100644
--- a/services/mirror/mirror_pull.go
+++ b/services/mirror/mirror_pull.go
@@ -203,11 +203,11 @@ func runSync(ctx context.Context, m *repo_model.Mirror) ([]*mirrorSyncResult, bo
 
 	log.Trace("SyncMirrors [repo: %-v]: running git remote update...", m.Repo)
 
-	gitArgs := []git.CmdArg{"remote", "update"}
+	cmd := git.NewCommand(ctx, "remote", "update")
 	if m.EnablePrune {
-		gitArgs = append(gitArgs, "--prune")
+		cmd.AddArguments("--prune")
 	}
-	gitArgs = append(gitArgs, git.CmdArgCheck(m.GetRemoteName()))
+	cmd.AddDynamicArguments(m.GetRemoteName())
 
 	remoteURL, remoteErr := git.GetRemoteURL(ctx, repoPath, m.GetRemoteName())
 	if remoteErr != nil {
@@ -217,7 +217,7 @@ func runSync(ctx context.Context, m *repo_model.Mirror) ([]*mirrorSyncResult, bo
 
 	stdoutBuilder := strings.Builder{}
 	stderrBuilder := strings.Builder{}
-	if err := git.NewCommand(ctx, gitArgs...).
+	if err := cmd.
 		SetDescription(fmt.Sprintf("Mirror.runSync: %s", m.Repo.FullName())).
 		Run(&git.RunOpts{
 			Timeout: timeout,
@@ -243,7 +243,7 @@ func runSync(ctx context.Context, m *repo_model.Mirror) ([]*mirrorSyncResult, bo
 				// Successful prune - reattempt mirror
 				stderrBuilder.Reset()
 				stdoutBuilder.Reset()
-				if err = git.NewCommand(ctx, gitArgs...).
+				if err = cmd.
 					SetDescription(fmt.Sprintf("Mirror.runSync: %s", m.Repo.FullName())).
 					Run(&git.RunOpts{
 						Timeout: timeout,
diff --git a/services/mirror/mirror_push.go b/services/mirror/mirror_push.go
index c0c68a3f54..2c1b00b60c 100644
--- a/services/mirror/mirror_push.go
+++ b/services/mirror/mirror_push.go
@@ -37,10 +37,10 @@ func AddPushMirrorRemote(ctx context.Context, m *repo_model.PushMirror, addr str
 		if _, _, err := cmd.RunStdString(&git.RunOpts{Dir: path}); err != nil {
 			return err
 		}
-		if _, _, err := git.NewCommand(ctx, "config", "--add", git.CmdArg("remote."+m.RemoteName+".push"), "+refs/heads/*:refs/heads/*").RunStdString(&git.RunOpts{Dir: path}); err != nil {
+		if _, _, err := git.NewCommand(ctx, "config", "--add").AddDynamicArguments("remote."+m.RemoteName+".push", "+refs/heads/*:refs/heads/*").RunStdString(&git.RunOpts{Dir: path}); err != nil {
 			return err
 		}
-		if _, _, err := git.NewCommand(ctx, "config", "--add", git.CmdArg("remote."+m.RemoteName+".push"), "+refs/tags/*:refs/tags/*").RunStdString(&git.RunOpts{Dir: path}); err != nil {
+		if _, _, err := git.NewCommand(ctx, "config", "--add").AddDynamicArguments("remote."+m.RemoteName+".push", "+refs/tags/*:refs/tags/*").RunStdString(&git.RunOpts{Dir: path}); err != nil {
 			return err
 		}
 		return nil
diff --git a/services/pull/merge.go b/services/pull/merge.go
index 7ffbdb78b0..edd5b601da 100644
--- a/services/pull/merge.go
+++ b/services/pull/merge.go
@@ -370,16 +370,16 @@ func rawMerge(ctx context.Context, pr *issues_model.PullRequest, doer *user_mode
 	sig := doer.NewGitSig()
 	committer := sig
 
-	// Determine if we should sign
-	var signArg git.CmdArg
-	sign, keyID, signer, _ := asymkey_service.SignMerge(ctx, pr, doer, tmpBasePath, "HEAD", trackingBranch)
+	// Determine if we should sign. If no signKeyID, use --no-gpg-sign to countermand the sign config (from gitconfig)
+	var signArgs git.TrustedCmdArgs
+	sign, signKeyID, signer, _ := asymkey_service.SignMerge(ctx, pr, doer, tmpBasePath, "HEAD", trackingBranch)
 	if sign {
-		signArg = git.CmdArg("-S" + keyID)
 		if pr.BaseRepo.GetTrustModel() == repo_model.CommitterTrustModel || pr.BaseRepo.GetTrustModel() == repo_model.CollaboratorCommitterTrustModel {
 			committer = signer
 		}
+		signArgs = git.ToTrustedCmdArgs([]string{"-S" + signKeyID})
 	} else {
-		signArg = git.CmdArg("--no-gpg-sign")
+		signArgs = append(signArgs, "--no-gpg-sign")
 	}
 
 	commitTimeStr := time.Now().Format(time.RFC3339)
@@ -403,7 +403,7 @@ func rawMerge(ctx context.Context, pr *issues_model.PullRequest, doer *user_mode
 			return "", err
 		}
 
-		if err := commitAndSignNoAuthor(ctx, pr, message, signArg, tmpBasePath, env); err != nil {
+		if err := commitAndSignNoAuthor(ctx, pr, message, signArgs, tmpBasePath, env); err != nil {
 			log.Error("Unable to make final commit: %v", err)
 			return "", err
 		}
@@ -505,7 +505,7 @@ func rawMerge(ctx context.Context, pr *issues_model.PullRequest, doer *user_mode
 			return "", err
 		}
 		if mergeStyle == repo_model.MergeStyleRebaseMerge {
-			if err := commitAndSignNoAuthor(ctx, pr, message, signArg, tmpBasePath, env); err != nil {
+			if err := commitAndSignNoAuthor(ctx, pr, message, signArgs, tmpBasePath, env); err != nil {
 				log.Error("Unable to make final commit: %v", err)
 				return "", err
 			}
@@ -523,35 +523,22 @@ func rawMerge(ctx context.Context, pr *issues_model.PullRequest, doer *user_mode
 			return "", fmt.Errorf("LoadPoster: %w", err)
 		}
 		sig := pr.Issue.Poster.NewGitSig()
-		if signArg == "" {
-			if err := git.NewCommand(ctx, "commit", git.CmdArg(fmt.Sprintf("--author='%s <%s>'", sig.Name, sig.Email)), "-m").AddDynamicArguments(message).
-				Run(&git.RunOpts{
-					Env:    env,
-					Dir:    tmpBasePath,
-					Stdout: &outbuf,
-					Stderr: &errbuf,
-				}); err != nil {
-				log.Error("git commit [%s:%s -> %s:%s]: %v\n%s\n%s", pr.HeadRepo.FullName(), pr.HeadBranch, pr.BaseRepo.FullName(), pr.BaseBranch, err, outbuf.String(), errbuf.String())
-				return "", fmt.Errorf("git commit [%s:%s -> %s:%s]: %w\n%s\n%s", pr.HeadRepo.FullName(), pr.HeadBranch, pr.BaseRepo.FullName(), pr.BaseBranch, err, outbuf.String(), errbuf.String())
-			}
-		} else {
-			if setting.Repository.PullRequest.AddCoCommitterTrailers && committer.String() != sig.String() {
-				// add trailer
-				message += fmt.Sprintf("\nCo-authored-by: %s\nCo-committed-by: %s\n", sig.String(), sig.String())
-			}
-			if err := git.NewCommand(ctx, "commit").
-				AddArguments(signArg).
-				AddArguments(git.CmdArg(fmt.Sprintf("--author='%s <%s>'", sig.Name, sig.Email))).
-				AddArguments("-m").AddDynamicArguments(message).
-				Run(&git.RunOpts{
-					Env:    env,
-					Dir:    tmpBasePath,
-					Stdout: &outbuf,
-					Stderr: &errbuf,
-				}); err != nil {
-				log.Error("git commit [%s:%s -> %s:%s]: %v\n%s\n%s", pr.HeadRepo.FullName(), pr.HeadBranch, pr.BaseRepo.FullName(), pr.BaseBranch, err, outbuf.String(), errbuf.String())
-				return "", fmt.Errorf("git commit [%s:%s -> %s:%s]: %w\n%s\n%s", pr.HeadRepo.FullName(), pr.HeadBranch, pr.BaseRepo.FullName(), pr.BaseBranch, err, outbuf.String(), errbuf.String())
-			}
+		if setting.Repository.PullRequest.AddCoCommitterTrailers && committer.String() != sig.String() {
+			// add trailer
+			message += fmt.Sprintf("\nCo-authored-by: %s\nCo-committed-by: %s\n", sig.String(), sig.String())
+		}
+		if err := git.NewCommand(ctx, "commit").
+			AddArguments(signArgs...).
+			AddOptionFormat("--author='%s <%s>'", sig.Name, sig.Email).
+			AddOptionValues("-m", message).
+			Run(&git.RunOpts{
+				Env:    env,
+				Dir:    tmpBasePath,
+				Stdout: &outbuf,
+				Stderr: &errbuf,
+			}); err != nil {
+			log.Error("git commit [%s:%s -> %s:%s]: %v\n%s\n%s", pr.HeadRepo.FullName(), pr.HeadBranch, pr.BaseRepo.FullName(), pr.BaseBranch, err, outbuf.String(), errbuf.String())
+			return "", fmt.Errorf("git commit [%s:%s -> %s:%s]: %w\n%s\n%s", pr.HeadRepo.FullName(), pr.HeadBranch, pr.BaseRepo.FullName(), pr.BaseBranch, err, outbuf.String(), errbuf.String())
 		}
 		outbuf.Reset()
 		errbuf.Reset()
@@ -649,30 +636,17 @@ func rawMerge(ctx context.Context, pr *issues_model.PullRequest, doer *user_mode
 	return mergeCommitID, nil
 }
 
-func commitAndSignNoAuthor(ctx context.Context, pr *issues_model.PullRequest, message string, signArg git.CmdArg, tmpBasePath string, env []string) error {
+func commitAndSignNoAuthor(ctx context.Context, pr *issues_model.PullRequest, message string, signArgs git.TrustedCmdArgs, tmpBasePath string, env []string) error {
 	var outbuf, errbuf strings.Builder
-	if signArg == "" {
-		if err := git.NewCommand(ctx, "commit", "-m").AddDynamicArguments(message).
-			Run(&git.RunOpts{
-				Env:    env,
-				Dir:    tmpBasePath,
-				Stdout: &outbuf,
-				Stderr: &errbuf,
-			}); err != nil {
-			log.Error("git commit [%s:%s -> %s:%s]: %v\n%s\n%s", pr.HeadRepo.FullName(), pr.HeadBranch, pr.BaseRepo.FullName(), pr.BaseBranch, err, outbuf.String(), errbuf.String())
-			return fmt.Errorf("git commit [%s:%s -> %s:%s]: %w\n%s\n%s", pr.HeadRepo.FullName(), pr.HeadBranch, pr.BaseRepo.FullName(), pr.BaseBranch, err, outbuf.String(), errbuf.String())
-		}
-	} else {
-		if err := git.NewCommand(ctx, "commit").AddArguments(signArg).AddArguments("-m").AddDynamicArguments(message).
-			Run(&git.RunOpts{
-				Env:    env,
-				Dir:    tmpBasePath,
-				Stdout: &outbuf,
-				Stderr: &errbuf,
-			}); err != nil {
-			log.Error("git commit [%s:%s -> %s:%s]: %v\n%s\n%s", pr.HeadRepo.FullName(), pr.HeadBranch, pr.BaseRepo.FullName(), pr.BaseBranch, err, outbuf.String(), errbuf.String())
-			return fmt.Errorf("git commit [%s:%s -> %s:%s]: %w\n%s\n%s", pr.HeadRepo.FullName(), pr.HeadBranch, pr.BaseRepo.FullName(), pr.BaseBranch, err, outbuf.String(), errbuf.String())
-		}
+	if err := git.NewCommand(ctx, "commit").AddArguments(signArgs...).AddOptionValues("-m", message).
+		Run(&git.RunOpts{
+			Env:    env,
+			Dir:    tmpBasePath,
+			Stdout: &outbuf,
+			Stderr: &errbuf,
+		}); err != nil {
+		log.Error("git commit [%s:%s -> %s:%s]: %v\n%s\n%s", pr.HeadRepo.FullName(), pr.HeadBranch, pr.BaseRepo.FullName(), pr.BaseBranch, err, outbuf.String(), errbuf.String())
+		return fmt.Errorf("git commit [%s:%s -> %s:%s]: %w\n%s\n%s", pr.HeadRepo.FullName(), pr.HeadBranch, pr.BaseRepo.FullName(), pr.BaseBranch, err, outbuf.String(), errbuf.String())
 	}
 	return nil
 }
diff --git a/services/pull/patch.go b/services/pull/patch.go
index a3084196bb..c2ccc75bdc 100644
--- a/services/pull/patch.go
+++ b/services/pull/patch.go
@@ -376,16 +376,16 @@ func checkConflicts(ctx context.Context, pr *issues_model.PullRequest, gitRepo *
 	prConfig := prUnit.PullRequestsConfig()
 
 	// 6. Prepare the arguments to apply the patch against the index
-	args := []git.CmdArg{"apply", "--check", "--cached"}
+	cmdApply := git.NewCommand(gitRepo.Ctx, "apply", "--check", "--cached")
 	if prConfig.IgnoreWhitespaceConflicts {
-		args = append(args, "--ignore-whitespace")
+		cmdApply.AddArguments("--ignore-whitespace")
 	}
 	is3way := false
 	if git.CheckGitVersionAtLeast("2.32.0") == nil {
-		args = append(args, "--3way")
+		cmdApply.AddArguments("--3way")
 		is3way = true
 	}
-	args = append(args, git.CmdArgCheck(patchPath))
+	cmdApply.AddDynamicArguments(patchPath)
 
 	// 7. Prep the pipe:
 	//   - Here we could do the equivalent of:
@@ -407,71 +407,70 @@ func checkConflicts(ctx context.Context, pr *issues_model.PullRequest, gitRepo *
 
 	// 8. Run the check command
 	conflict = false
-	err = git.NewCommand(gitRepo.Ctx, args...).
-		Run(&git.RunOpts{
-			Dir:    tmpBasePath,
-			Stderr: stderrWriter,
-			PipelineFunc: func(ctx context.Context, cancel context.CancelFunc) error {
-				// Close the writer end of the pipe to begin processing
-				_ = stderrWriter.Close()
-				defer func() {
-					// Close the reader on return to terminate the git command if necessary
-					_ = stderrReader.Close()
-				}()
-
-				const prefix = "error: patch failed:"
-				const errorPrefix = "error: "
-				const threewayFailed = "Failed to perform three-way merge..."
-				const appliedPatchPrefix = "Applied patch to '"
-				const withConflicts = "' with conflicts."
-
-				conflicts := make(container.Set[string])
-
-				// Now scan the output from the command
-				scanner := bufio.NewScanner(stderrReader)
-				for scanner.Scan() {
-					line := scanner.Text()
-					log.Trace("PullRequest[%d].testPatch: stderr: %s", pr.ID, line)
-					if strings.HasPrefix(line, prefix) {
-						conflict = true
-						filepath := strings.TrimSpace(strings.Split(line[len(prefix):], ":")[0])
-						conflicts.Add(filepath)
-					} else if is3way && line == threewayFailed {
-						conflict = true
-					} else if strings.HasPrefix(line, errorPrefix) {
-						conflict = true
-						for _, suffix := range patchErrorSuffices {
-							if strings.HasSuffix(line, suffix) {
-								filepath := strings.TrimSpace(strings.TrimSuffix(line[len(errorPrefix):], suffix))
-								if filepath != "" {
-									conflicts.Add(filepath)
-								}
-								break
+	err = cmdApply.Run(&git.RunOpts{
+		Dir:    tmpBasePath,
+		Stderr: stderrWriter,
+		PipelineFunc: func(ctx context.Context, cancel context.CancelFunc) error {
+			// Close the writer end of the pipe to begin processing
+			_ = stderrWriter.Close()
+			defer func() {
+				// Close the reader on return to terminate the git command if necessary
+				_ = stderrReader.Close()
+			}()
+
+			const prefix = "error: patch failed:"
+			const errorPrefix = "error: "
+			const threewayFailed = "Failed to perform three-way merge..."
+			const appliedPatchPrefix = "Applied patch to '"
+			const withConflicts = "' with conflicts."
+
+			conflicts := make(container.Set[string])
+
+			// Now scan the output from the command
+			scanner := bufio.NewScanner(stderrReader)
+			for scanner.Scan() {
+				line := scanner.Text()
+				log.Trace("PullRequest[%d].testPatch: stderr: %s", pr.ID, line)
+				if strings.HasPrefix(line, prefix) {
+					conflict = true
+					filepath := strings.TrimSpace(strings.Split(line[len(prefix):], ":")[0])
+					conflicts.Add(filepath)
+				} else if is3way && line == threewayFailed {
+					conflict = true
+				} else if strings.HasPrefix(line, errorPrefix) {
+					conflict = true
+					for _, suffix := range patchErrorSuffices {
+						if strings.HasSuffix(line, suffix) {
+							filepath := strings.TrimSpace(strings.TrimSuffix(line[len(errorPrefix):], suffix))
+							if filepath != "" {
+								conflicts.Add(filepath)
 							}
-						}
-					} else if is3way && strings.HasPrefix(line, appliedPatchPrefix) && strings.HasSuffix(line, withConflicts) {
-						conflict = true
-						filepath := strings.TrimPrefix(strings.TrimSuffix(line, withConflicts), appliedPatchPrefix)
-						if filepath != "" {
-							conflicts.Add(filepath)
+							break
 						}
 					}
-					// only list 10 conflicted files
-					if len(conflicts) >= 10 {
-						break
+				} else if is3way && strings.HasPrefix(line, appliedPatchPrefix) && strings.HasSuffix(line, withConflicts) {
+					conflict = true
+					filepath := strings.TrimPrefix(strings.TrimSuffix(line, withConflicts), appliedPatchPrefix)
+					if filepath != "" {
+						conflicts.Add(filepath)
 					}
 				}
+				// only list 10 conflicted files
+				if len(conflicts) >= 10 {
+					break
+				}
+			}
 
-				if len(conflicts) > 0 {
-					pr.ConflictedFiles = make([]string, 0, len(conflicts))
-					for key := range conflicts {
-						pr.ConflictedFiles = append(pr.ConflictedFiles, key)
-					}
+			if len(conflicts) > 0 {
+				pr.ConflictedFiles = make([]string, 0, len(conflicts))
+				for key := range conflicts {
+					pr.ConflictedFiles = append(pr.ConflictedFiles, key)
 				}
+			}
 
-				return nil
-			},
-		})
+			return nil
+		},
+	})
 
 	// 9. Check if the found conflictedfiles is non-zero, "err" could be non-nil, so we should ignore it if we found conflicts.
 	// Note: `"err" could be non-nil` is due that if enable 3-way merge, it doesn't return any error on found conflicts.
diff --git a/services/repository/check.go b/services/repository/check.go
index e9d65aea4a..3a1f0b7f30 100644
--- a/services/repository/check.go
+++ b/services/repository/check.go
@@ -23,7 +23,7 @@ import (
 )
 
 // GitFsckRepos calls 'git fsck' to check repository health.
-func GitFsckRepos(ctx context.Context, timeout time.Duration, args []git.CmdArg) error {
+func GitFsckRepos(ctx context.Context, timeout time.Duration, args git.TrustedCmdArgs) error {
 	log.Trace("Doing: GitFsck")
 
 	if err := db.Iterate(
@@ -47,10 +47,10 @@ func GitFsckRepos(ctx context.Context, timeout time.Duration, args []git.CmdArg)
 }
 
 // GitFsckRepo calls 'git fsck' to check an individual repository's health.
-func GitFsckRepo(ctx context.Context, repo *repo_model.Repository, timeout time.Duration, args []git.CmdArg) error {
+func GitFsckRepo(ctx context.Context, repo *repo_model.Repository, timeout time.Duration, args git.TrustedCmdArgs) error {
 	log.Trace("Running health check on repository %-v", repo)
 	repoPath := repo.RepoPath()
-	if err := git.Fsck(ctx, repoPath, timeout, args...); err != nil {
+	if err := git.Fsck(ctx, repoPath, timeout, args); err != nil {
 		log.Warn("Failed to health check repository (%-v): %v", repo, err)
 		if err = system_model.CreateRepositoryNotice("Failed to health check repository (%s): %v", repo.FullName(), err); err != nil {
 			log.Error("CreateRepositoryNotice: %v", err)
@@ -60,9 +60,8 @@ func GitFsckRepo(ctx context.Context, repo *repo_model.Repository, timeout time.
 }
 
 // GitGcRepos calls 'git gc' to remove unnecessary files and optimize the local repository
-func GitGcRepos(ctx context.Context, timeout time.Duration, args ...git.CmdArg) error {
+func GitGcRepos(ctx context.Context, timeout time.Duration, args git.TrustedCmdArgs) error {
 	log.Trace("Doing: GitGcRepos")
-	args = append([]git.CmdArg{"gc"}, args...)
 
 	if err := db.Iterate(
 		ctx,
@@ -86,9 +85,9 @@ func GitGcRepos(ctx context.Context, timeout time.Duration, args ...git.CmdArg)
 }
 
 // GitGcRepo calls 'git gc' to remove unnecessary files and optimize the local repository
-func GitGcRepo(ctx context.Context, repo *repo_model.Repository, timeout time.Duration, args []git.CmdArg) error {
+func GitGcRepo(ctx context.Context, repo *repo_model.Repository, timeout time.Duration, args git.TrustedCmdArgs) error {
 	log.Trace("Running git gc on %-v", repo)
-	command := git.NewCommand(ctx, args...).
+	command := git.NewCommand(ctx, "gc").AddArguments(args...).
 		SetDescription(fmt.Sprintf("Repository Garbage Collection: %s", repo.FullName()))
 	var stdout string
 	var err error
diff --git a/services/repository/files/patch.go b/services/repository/files/patch.go
index 73ee0fa815..f65199cfcb 100644
--- a/services/repository/files/patch.go
+++ b/services/repository/files/patch.go
@@ -141,14 +141,12 @@ func ApplyDiffPatch(ctx context.Context, repo *repo_model.Repository, doer *user
 	stdout := &strings.Builder{}
 	stderr := &strings.Builder{}
 
-	args := []git.CmdArg{"apply", "--index", "--recount", "--cached", "--ignore-whitespace", "--whitespace=fix", "--binary"}
-
+	cmdApply := git.NewCommand(ctx, "apply", "--index", "--recount", "--cached", "--ignore-whitespace", "--whitespace=fix", "--binary")
 	if git.CheckGitVersionAtLeast("2.32") == nil {
-		args = append(args, "-3")
+		cmdApply.AddArguments("-3")
 	}
 
-	cmd := git.NewCommand(ctx, args...)
-	if err := cmd.Run(&git.RunOpts{
+	if err := cmdApply.Run(&git.RunOpts{
 		Dir:    t.basePath,
 		Stdout: stdout,
 		Stderr: stderr,
diff --git a/services/repository/files/temp_repo.go b/services/repository/files/temp_repo.go
index 1f3375cdcc..a086d15a4f 100644
--- a/services/repository/files/temp_repo.go
+++ b/services/repository/files/temp_repo.go
@@ -233,11 +233,9 @@ func (t *TemporaryUploadRepository) CommitTreeWithDate(parent string, author, co
 	_, _ = messageBytes.WriteString(message)
 	_, _ = messageBytes.WriteString("\n")
 
-	var args []git.CmdArg
+	cmdCommitTree := git.NewCommand(t.ctx, "commit-tree").AddDynamicArguments(treeHash)
 	if parent != "" {
-		args = []git.CmdArg{"commit-tree", git.CmdArgCheck(treeHash), "-p", git.CmdArgCheck(parent)}
-	} else {
-		args = []git.CmdArg{"commit-tree", git.CmdArgCheck(treeHash)}
+		cmdCommitTree.AddOptionValues("-p", parent)
 	}
 
 	var sign bool
@@ -249,7 +247,7 @@ func (t *TemporaryUploadRepository) CommitTreeWithDate(parent string, author, co
 		sign, keyID, signer, _ = asymkey_service.SignInitialCommit(t.ctx, t.repo.RepoPath(), author)
 	}
 	if sign {
-		args = append(args, git.CmdArg("-S"+keyID))
+		cmdCommitTree.AddOptionFormat("-S%s", keyID)
 		if t.repo.GetTrustModel() == repo_model.CommitterTrustModel || t.repo.GetTrustModel() == repo_model.CollaboratorCommitterTrustModel {
 			if committerSig.Name != authorSig.Name || committerSig.Email != authorSig.Email {
 				// Add trailers
@@ -264,7 +262,7 @@ func (t *TemporaryUploadRepository) CommitTreeWithDate(parent string, author, co
 			committerSig = signer
 		}
 	} else {
-		args = append(args, "--no-gpg-sign")
+		cmdCommitTree.AddArguments("--no-gpg-sign")
 	}
 
 	if signoff {
@@ -281,7 +279,7 @@ func (t *TemporaryUploadRepository) CommitTreeWithDate(parent string, author, co
 
 	stdout := new(bytes.Buffer)
 	stderr := new(bytes.Buffer)
-	if err := git.NewCommand(t.ctx, args...).
+	if err := cmdCommitTree.
 		Run(&git.RunOpts{
 			Env:    env,
 			Dir:    t.basePath,
@@ -364,7 +362,7 @@ func (t *TemporaryUploadRepository) DiffIndex() (*gitdiff.Diff, error) {
 			t.repo.FullName(), err, stderr)
 	}
 
-	diff.NumFiles, diff.TotalAddition, diff.TotalDeletion, err = git.GetDiffShortStat(t.ctx, t.basePath, "--cached", "HEAD")
+	diff.NumFiles, diff.TotalAddition, diff.TotalDeletion, err = git.GetDiffShortStat(t.ctx, t.basePath, git.TrustedCmdArgs{"--cached"}, "HEAD")
 	if err != nil {
 		return nil, err
 	}
diff --git a/services/repository/files/update.go b/services/repository/files/update.go
index 58b7a5e082..45a4692396 100644
--- a/services/repository/files/update.go
+++ b/services/repository/files/update.go
@@ -370,7 +370,7 @@ func CreateOrUpdateRepoFile(ctx context.Context, repo *repo_model.Repository, do
 	if setting.LFS.StartServer && hasOldBranch {
 		// Check there is no way this can return multiple infos
 		filename2attribute2info, err := t.gitRepo.CheckAttribute(git.CheckAttributeOpts{
-			Attributes: []git.CmdArg{"filter"},
+			Attributes: []string{"filter"},
 			Filenames:  []string{treePath},
 			CachedOnly: true,
 		})
diff --git a/services/repository/files/upload.go b/services/repository/files/upload.go
index e7289dd60d..cf2f7019b6 100644
--- a/services/repository/files/upload.go
+++ b/services/repository/files/upload.go
@@ -96,7 +96,7 @@ func UploadRepoFiles(ctx context.Context, repo *repo_model.Repository, doer *use
 	var filename2attribute2info map[string]map[string]string
 	if setting.LFS.StartServer {
 		filename2attribute2info, err = t.gitRepo.CheckAttribute(git.CheckAttributeOpts{
-			Attributes: []git.CmdArg{"filter"},
+			Attributes: []string{"filter"},
 			Filenames:  names,
 			CachedOnly: true,
 		})