Fall back to Process.gid if we aren't a member of the file's group

1 files changed, 4 insertions, 1 deletions

diff --git a/Library/Homebrew/extend/pathname.rb b/Library/Homebrew/extend/pathname.rb
index cb76c8910..c9c233144 100644
--- a/Library/Homebrew/extend/pathname.rb
+++ b/Library/Homebrew/extend/pathname.rb
@@ -110,8 +110,11 @@ class Pathname
 
     FileUtils.mv tf.path, self
 
+    uid = Process.uid
+    gid = Process.groups.delete(old_stat.gid) { Process.gid }
+
     begin
-      chown(old_stat.uid, old_stat.gid)
+      chown(uid, gid)
       chmod(old_stat.mode)
     rescue Errno::EPERM
     end