Function getRepoChanges

agent/agentgit/agentgit.go:353–394

getRepoChanges reads the current state of a git repository using the git CLI. It returns branch, remote origin, and a unified diff.

(ctx context.Context, logger slog.Logger, gitBin string, repoRoot string)

// getRepoChanges reads the current state of a git repository using
// the git CLI. It returns branch, remote origin, and a unified diff.
func getRepoChanges(ctx context.Context, logger slog.Logger, gitBin string, repoRoot string) (codersdk.WorkspaceAgentRepoChanges, error) {
	result := codersdk.WorkspaceAgentRepoChanges{
		RepoRoot: repoRoot,
	}

	// Verify this is still a valid git repository before doing
	// anything else. This catches deleted repos early.
	verifyCmd := exec.CommandContext(ctx, gitBin, "-C", repoRoot, "rev-parse", "--git-dir")
	if err := verifyCmd.Run(); err != nil {
		return result, xerrors.Errorf("not a git repository: %w", err)
	}

	// Read branch name.
	branchCmd := exec.CommandContext(ctx, gitBin, "-C", repoRoot, "symbolic-ref", "--short", "HEAD")
	if out, err := branchCmd.Output(); err == nil {
		result.Branch = strings.TrimSpace(string(out))
	} else {
		logger.Debug(ctx, "failed to read HEAD", slog.F("root", repoRoot), slog.Error(err))
	}

	// Read remote origin URL.
	remoteCmd := exec.CommandContext(ctx, gitBin, "-C", repoRoot, "config", "--get", "remote.origin.url")
	if out, err := remoteCmd.Output(); err == nil {
		result.RemoteOrigin = strings.TrimSpace(string(out))
	}

	// Compute unified diff.
	// `git diff HEAD` shows both staged and unstaged changes vs HEAD.
	// For repos with no commits yet, fall back to showing untracked
	// files only.
	diff, err := computeGitDiff(ctx, logger, gitBin, repoRoot)
	if err != nil {
		return result, xerrors.Errorf("compute diff: %w", err)
	}

	result.UnifiedDiff = diff
	if len(result.UnifiedDiff) > maxTotalDiffSize {
		result.UnifiedDiff = "Total diff too large to show. Size: " + humanize.IBytes(uint64(len(result.UnifiedDiff))) + ". Showing branch and remote only."
	}

	return result, nil
}

// computeGitDiff produces a unified diff string for the repository by
// combining `git diff HEAD` (staged + unstaged changes) with diffs