Return 400 error when Branches API receives an invalid regex

Vasilii Iakliushinrequested to merge
vi-fix-regexp-error-handling into master

What does this MR do and why?

Sentry error: https://new-sentry.gitlab.net/organizations/gitlab/issues/1805395

Problem

Regexp parser can raise 'RegexpError' exception that is currently unhandled. As a result, the user will see a 500 server error.

Solution

Capture 'RegexpError' exception and respond with 400 error with an message explaining what is wrong.

How to set up and validate locally

  1. Visit http://gdk.test:3000/api/v4/projects/1/repository/branches?regex=wrong(
  2. It should return an 400 error with an error message

Screenshot_2025-08-08_at_17.09.46

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Edited by Vasilii Iakliushin

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