"demo.key" file creation in UI not blocked by secret prevention Push Rules

Summary

A large Self-Managed Ultimate customer tried to use the option to prevent pushing secrets to the repository but was still able to create a file named demo.key by using the browser-based file creation flow.

Steps to reproduce

1. Enable the option to prevent pushing secrets
2. Go to a project and use the + button to add a new file with a name that should be blocked

Example Project

Example project is not available.

Video snippet here (team members only)

What is the current bug behavior?

File is allowed to be created

What is the expected correct behavior?

File is not allowed to be created

Relevant logs and/or screenshots

See video above

Output of checks

Can be gathered if needed

Results of GitLab environment info

Can be gathered if needed.

Version 14.9.2, Self-Managed, Ultimate

Expand for output related to GitLab environment info

(For installations with omnibus-gitlab package run and paste the output of:
`sudo gitlab-rake gitlab:env:info`)

(For installations from source run and paste the output of:
`sudo -u git -H bundle exec rake gitlab:env:info RAILS_ENV=production`)

Results of GitLab application Check

Can be gathered if needed

Expand for output related to the GitLab application check

(For installations with omnibus-gitlab package run and paste the output of:
sudo gitlab-rake gitlab:check SANITIZE=true)
(For installations from source run and paste the output of:
sudo -u git -H bundle exec rake gitlab:check RAILS_ENV=production SANITIZE=true)
(we will only investigate if the tests are passing)

Possible fixes