func revIsHash()

in cmd/git-sync/main.go [955:975]

• 15 lines of code
• 4 McCabe index (conditional complexity)

func revIsHash(ctx context.Context, rev, gitRoot string) (bool, error) {
	// If git doesn't identify rev as a commit, we're done.
	output, err := cmdRunner.Run(ctx, gitRoot, *flGitCmd, "cat-file", "-t", rev)
	if err != nil {
		return false, err
	}
	o := strings.Trim(string(output), "\n")
	if o != "commit" {
		return false, nil
	}

	// `git cat-file -t` also returns "commit" for tags. If rev is already a git
	// hash, the output will be the same hash as the input.  Of course, a user
	// could specify "abc" and match "abcdef12345678", so we just do a prefix
	// match.
	output, err = localHashForRev(ctx, rev, gitRoot)
	if err != nil {
		return false, err
	}
	return strings.HasPrefix(output, rev), nil
}