fix: address third round of PR review feedback

- Remove nil check on ctx in gitCmd (callers always provide non-nil ctx)
- Remove stdin parameter from gitPipeline (no production caller uses it)
- Rewrite isExitStatus to use run.ExitCoder interface instead of string
  parsing, as suggested by reviewer
- Remove unused errors and os/exec imports
- Update tests to use gitCmd directly for stdin-based scenarios

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: unknwon

blob.go

@@ -34,5 +34,5 @@ func (b *Blob) Bytes(ctx context.Context) ([]byte, error) {
 // Pipeline reads the content of the blob and pipes stdout and stderr to
 // supplied io.Writer.
 func (b *Blob) Pipeline(ctx context.Context, stdout, stderr io.Writer) error {
-	return gitPipeline(ctx, b.parent.repo.path, []string{"show", b.id.String()}, nil, stdout, stderr, nil)
+	return gitPipeline(ctx, b.parent.repo.path, []string{"show", b.id.String()}, nil, stdout, stderr)
 }

command.go

@@ -7,11 +7,9 @@ package git
 import (
 	"bytes"
 	"context"
-	"errors"
 	"fmt"
 	"io"
 	"os"
-	"os/exec"
 	"strconv"
 	"strings"
 	"time"
@@ -33,9 +31,6 @@ const DefaultTimeout = time.Minute
 // variables and working directory. If the context does not already have a
 // deadline, DefaultTimeout will be applied automatically.
 func gitCmd(ctx context.Context, dir string, args []string, envs []string) (*run.Command, context.CancelFunc) {
-	if ctx == nil {
-		ctx = context.Background()
-	}
 	cancel := func() {}
 
 	// Apply default timeout if the context doesn't already have a deadline.
@@ -109,13 +104,10 @@ func gitRun(ctx context.Context, dir string, args []string, envs []string) ([]by
 
 // gitPipeline executes a git command in the given directory, streaming stdout
 // to the given writer. If stderr writer is provided and the command fails,
-// stderr content extracted from the error is written to it. stdin is optional.
-func gitPipeline(ctx context.Context, dir string, args []string, envs []string, stdout, stderr io.Writer, stdin io.Reader) error {
+// stderr content extracted from the error is written to it.
+func gitPipeline(ctx context.Context, dir string, args []string, envs []string, stdout, stderr io.Writer) error {
 	cmd, cancel := gitCmd(ctx, dir, args, envs)
 	defer cancel()
-	if stdin != nil {
-		cmd = cmd.Input(stdin)
-	}
 
 	var buf *bytes.Buffer
 	w := stdout
@@ -216,15 +208,10 @@ func mapContextError(err error, ctx context.Context) error {
 }
 
 // isExitStatus reports whether err represents a specific process exit status
-// code. It handles both the bare "exit status N" format and the
-// "exit status N: <stderr>" format produced by sourcegraph/run.
+// code, using the run.ExitCoder interface provided by sourcegraph/run.
 func isExitStatus(err error, code int) bool {
-	if err == nil {
-		return false
-	}
-	prefix := fmt.Sprintf("exit status %d", code)
-	msg := err.Error()
-	return msg == prefix || strings.HasPrefix(msg, prefix+":")
+	exitCoder, ok := err.(run.ExitCoder)
+	return ok && exitCoder.ExitCode() == code
 }
 
 // extractStderr attempts to extract the stderr portion from a sourcegraph/run
@@ -233,10 +220,6 @@ func extractStderr(err error) string {
 	if err == nil {
 		return ""
 	}
-	var exitErr *exec.ExitError
-	if errors.As(err, &exitErr) && len(exitErr.Stderr) > 0 {
-		return string(exitErr.Stderr)
-	}
 	msg := err.Error()
 	// sourcegraph/run error format: "exit status N: <stderr>"
 	if idx := strings.Index(msg, ": "); idx >= 0 && strings.HasPrefix(msg, "exit status") {

command_test.go

@@ -26,9 +26,13 @@ func TestGitRun_ContextTimeout(t *testing.T) {
 		ctx, cancel := context.WithTimeout(context.Background(), 100*time.Millisecond)
 		defer cancel()
 
-		// Use a blocking reader so the command starts successfully and blocks
-		// reading stdin until the context deadline fires.
-		err := gitPipeline(ctx, "", []string{"hash-object", "--stdin"}, nil, io.Discard, io.Discard, blockingReader{cancel: ctx.Done()})
+		// Use gitCmd directly with a blocking stdin so the command starts
+		// successfully and blocks reading until the context deadline fires.
+		cmd, timeoutCancel := gitCmd(ctx, "", []string{"hash-object", "--stdin"}, nil)
+		defer timeoutCancel()
+
+		err := cmd.Input(blockingReader{cancel: ctx.Done()}).StdOut().Run().Stream(io.Discard)
+		err = mapContextError(err, ctx)
 		assert.Equal(t, ErrExecTimeout, err)
 	})
 }
@@ -46,7 +50,7 @@ func (r blockingReader) Read(p []byte) (int, error) {
 	return 0, io.EOF
 }
 
-func TestGitPipeline_ContextCancellation(t *testing.T) {
+func TestGitCmd_ContextCancellation(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 
 	// Cancel in the background after a short delay so the command is already
@@ -58,7 +62,11 @@ func TestGitPipeline_ContextCancellation(t *testing.T) {
 		close(done)
 	}()
 
-	err := gitPipeline(ctx, "", []string{"hash-object", "--stdin"}, nil, io.Discard, io.Discard, blockingReader{cancel: done})
+	cmd, timeoutCancel := gitCmd(ctx, "", []string{"hash-object", "--stdin"}, nil)
+	defer timeoutCancel()
+
+	err := cmd.Input(blockingReader{cancel: done}).StdOut().Run().Stream(io.Discard)
+	err = mapContextError(err, ctx)
 	assert.ErrorIs(t, err, context.Canceled)
 	// Must NOT be ErrExecTimeout — cancellation is distinct from deadline.
 	assert.NotEqual(t, ErrExecTimeout, err)

repo.go

@@ -448,7 +448,7 @@ func (r *Repository) ShowNameStatus(ctx context.Context, rev string, opts ...Sho
 	args = append(args, opt.Args...)
 	args = append(args, "--end-of-options", rev)
 
-	err := gitPipeline(ctx, r.path, args, opt.Envs, w, nil, nil)
+	err := gitPipeline(ctx, r.path, args, opt.Envs, w, nil)
 	_ = w.Close() // Close writer to exit parsing goroutine
 	if err != nil {
 		return nil, err

repo_diff.go

@@ -59,7 +59,7 @@ func (r *Repository) Diff(ctx context.Context, rev string, maxFiles, maxFileLine
 	done := make(chan SteamParseDiffResult)
 	go StreamParseDiff(stdout, done, maxFiles, maxFileLines, maxLineChars)
 
-	err = gitPipeline(ctx, r.path, args, opt.Envs, w, nil, nil)
+	err = gitPipeline(ctx, r.path, args, opt.Envs, w, nil)
 	_ = w.Close() // Close writer to exit parsing goroutine
 	if err != nil {
 		return nil, err
@@ -132,7 +132,7 @@ func (r *Repository) RawDiff(ctx context.Context, rev string, diffType RawDiffFo
 		return fmt.Errorf("invalid diffType: %s", diffType)
 	}
 
-	if err = gitPipeline(ctx, r.path, args, opt.Envs, w, nil, nil); err != nil {
+	if err = gitPipeline(ctx, r.path, args, opt.Envs, w, nil); err != nil {
 		return err
 	}
 	return nil