From 98016b0ac61c3e078a4df34f1ec5d2792958dcd4 Mon Sep 17 00:00:00 2001
From: Chongyu Zhu <i@lembacon.com>
Date: Sun, 21 Oct 2018 08:58:16 +0800
Subject: [PATCH] pathname: `atomic_write` shouldn't make dir sticky unless
 world writable

---
 Library/Homebrew/extend/pathname.rb | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/Library/Homebrew/extend/pathname.rb b/Library/Homebrew/extend/pathname.rb
index 1f67eab52b..513e112908 100644
--- a/Library/Homebrew/extend/pathname.rb
+++ b/Library/Homebrew/extend/pathname.rb
@@ -165,13 +165,14 @@ class Pathname
     # The enclosing `mktmpdir` and the `chmod` are a workaround
     # for https://github.com/rails/rails/pull/34037.
     Dir.mktmpdir(".d", dirname) do |tmpdir|
+      should_fix_sticky_bit = dirname.world_writable? && !dirname.sticky?
+      FileUtils.chmod "+t", dirname if should_fix_sticky_bit
       begin
-        FileUtils.chmod "+t", dirname
-      rescue Errno::EPERM
-        :ignore
-      end
-      File.atomic_write(self, tmpdir) do |file|
-        file.write(content)
+        File.atomic_write(self, tmpdir) do |file|
+          file.write(content)
+        end
+      ensure
+        FileUtils.chmod "-t", dirname if should_fix_sticky_bit
       end
     end
   end