Clean environment variables when running git hooks

CHANGELOG

@@ -135,6 +135,7 @@ v 8.12.0 (unreleased)
   - Return 204 instead of 404 for /ci/api/v1/builds/register.json if no builds are scheduled for a runner !6225
   - Fix Gitlab::Popen.popen thread-safety issue
   - Add specs to removing project (Katarzyna Kobierska Ula Budziszewska)
+  - Clean environment variables when running git hooks
 
 v 8.11.6
   - Fix unnecessary horizontal scroll area in pipeline visualizations. !6005

lib/gitlab/git/hook.rb

@@ -17,6 +17,7 @@ module Gitlab
       def trigger(gl_id, oldrev, newrev, ref)
         return [true, nil] unless exists?
 
+        Bundler.with_clean_env do
           case name
           when "pre-receive", "post-receive"
             call_receive_hook(gl_id, oldrev, newrev, ref)
@@ -24,6 +25,7 @@ module Gitlab
             call_update_hook(gl_id, oldrev, newrev, ref)
           end
         end
+      end
 
       private