WIP

revgrep.go

@@ -411,8 +411,50 @@ func GitPatch(revisionFrom, revisionTo string) (io.Reader, []string, error) {
 func gitDiff(extraArgs ...string) *exec.Cmd {
 	cmd := exec.Command("git", "diff", "--color=never", "--no-ext-diff")
 
+	if isSupportedByGit(2, 41, 0) {
+		cmd.Args = append(cmd.Args, "--default-prefix")
+	}
+
 	cmd.Args = append(cmd.Args, "--relative")
 	cmd.Args = append(cmd.Args, extraArgs...)
 
 	return cmd
 }
+
+func isSupportedByGit(major, minor, patch int) bool {
+	output, err := exec.Command("git", "version").CombinedOutput()
+	if err != nil {
+		return false
+	}
+
+	fmt.Println(string(output))
+
+	parts := bytes.Split(bytes.TrimSpace(output), []byte(" "))
+	if len(parts) < 3 {
+		return false
+	}
+
+	v := string(parts[2])
+	if v == "" {
+		return false
+	}
+
+	vp := regexp.MustCompile(`^(\d+)\.(\d+)(?:\.(\d+))?$`).FindStringSubmatch(v)
+
+	currentMajor, err := strconv.Atoi(vp[1])
+	if err != nil {
+		return false
+	}
+
+	currentMinor, err := strconv.Atoi(vp[2])
+	if err != nil {
+		return false
+	}
+
+	currentPatch, err := strconv.Atoi(vp[3])
+	if err != nil {
+		return false
+	}
+
+	return currentMajor*1_000_000_000+currentMinor*1_000_000+currentPatch*1_000 >= major*1_000_000_000+minor*1_000_000+patch*1_000
+}