From 78d2c617edad58da6ba537c9b65a80ac0d1b3574 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=B6ran=20Karl?=
 <3951388+JoeKar@users.noreply.github.com>
Date: Mon, 14 Jul 2025 22:38:41 +0200
Subject: [PATCH] util: Hash the path in `DetermineEscapePath()`

...in case the escaped path exceeds the file name length limit
---
 internal/util/util.go | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/internal/util/util.go b/internal/util/util.go
index d0f20022..86351853 100644
--- a/internal/util/util.go
+++ b/internal/util/util.go
@@ -3,6 +3,7 @@ package util
 import (
 	"archive/zip"
 	"bytes"
+	"crypto/md5"
 	"errors"
 	"fmt"
 	"io"
@@ -450,6 +451,10 @@ func AppendBackupSuffix(path string) string {
 	return path + ".micro-backup"
 }
 
+func HashStringMd5(str string) string {
+	return fmt.Sprintf("%x", md5.Sum([]byte(str)))
+}
+
 // EscapePathUrl encodes the path in URL query form
 func EscapePathUrl(path string) string {
 	return url.QueryEscape(filepath.ToSlash(path))
@@ -469,6 +474,8 @@ func EscapePathLegacy(path string) string {
 // using URL encoding (preferred, since it encodes unambiguously) or
 // legacy encoding with '%' (for backward compatibility, if the legacy-escaped
 // path exists in the given directory).
+// In case the length of the escaped path (plus the backup extension) exceeds
+// the filename length limit, a hash of the path is returned instead.
 func DetermineEscapePath(dir string, path string) string {
 	url := filepath.Join(dir, EscapePathUrl(path))
 	if _, err := os.Stat(url); err == nil {
@@ -480,6 +487,10 @@ func DetermineEscapePath(dir string, path string) string {
 		return legacy
 	}
 
+	if len(url)+len(".micro-backup") > 255 {
+		return filepath.Join(dir, HashStringMd5(path))
+	}
+
 	return url
 }