From f72b9824f3d650ba587a5ff9f82164685fbb0ccf Mon Sep 17 00:00:00 2001
From: Sergey Sharybin <sergey@blender.org>
Date: Wed, 4 Nov 2020 11:39:40 +0100
Subject: [PATCH] Do not overwrite files if they did not change

This causes an extra file read, but the benefit is that it is easier
to compare data on the file system, quickly see what did actually change
and what did not.
---
 scripts/gitolite/rebuild_gitolite.php | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/scripts/gitolite/rebuild_gitolite.php b/scripts/gitolite/rebuild_gitolite.php
index a19be6c898..c549526075 100755
--- a/scripts/gitolite/rebuild_gitolite.php
+++ b/scripts/gitolite/rebuild_gitolite.php
@@ -24,6 +24,17 @@ function endswith($string, $suffix) {
                 $suffix_length) == $suffix;
 }
 
+function file_put_contents_if_different($file_name, $content) {
+  if (file_exists($file_name)) {
+    $current_content = file_get_contents($file_name);
+    if ($current_content == $content) {
+      return;
+    }
+  }
+
+  file_put_contents($file_name, $content);
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // Phabricator access list traversal.
 
@@ -76,8 +87,8 @@ class Configuration {
 
     if (!array_key_exists($config_user_name, $this->used_keys)) {
       $this->used_keys[$config_user_name] = true;
-      file_put_contents("$this->keys_directory/$config_user_name.pub",
-                        $full_key_content);
+      file_put_contents_if_different("$this->keys_directory/$config_user_name.pub",
+                                     $full_key_content);
     }
 
     return $config_user_name;
@@ -110,7 +121,7 @@ class Configuration {
       $new_config .= $line . "\n";
     }
 
-    file_put_contents($this->config_file, trim($new_config) . "\n");
+    file_put_contents_if_different($this->config_file, trim($new_config) . "\n");
   }
 
   protected function getNonPhabtricatorUsers($configuration_value) {