@@ -0,0 +1,35 @@
+package git
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"os/exec"
+)
+
+func IsGitRepo(ctx context.Context, wd string) (bool, string, error) {
+	root, err := showRoot(ctx, wd)
+	if err != nil {
+		var exitErr *exec.ExitError
+		if errors.As(err, &exitErr) {
+			if exitErr.ExitCode() == 128 {
+				return false, wd, nil
+			}
+		}
+
+		return false, wd, err
+	}
+
+	return root != "", root, nil
+}
+
+func showRoot(ctx context.Context, wd string) (string, error) {
+	cmd := exec.CommandContext(ctx, "git", "rev-parse", "--show-toplevel")
+	cmd.Dir = wd
+	rr, err := cmd.Output()
+	if err != nil {
+		return "", err
+	}
+
+	return string(bytes.TrimSpace(rr)), nil
+}