GitLab Connector: hard-coded master branch makes a 404 error

[ThomaciousD]

The current implementation of the Onyx GitLab connector assumes the branch name to be master when accessing repository files. This assumption causes 404 errors when working with repositories that use a different default branch name, such as main or other custom branch names.

The issue specifically arises in the following part of the code:

onyx/backend/onyx/connectors/gitlab/connector.py

Line 92 in 6551d6b

file_path=file["path"], ref="master"

This causes the API calls to fail when the repository does not have a master branch.

[rkuo-danswer]

Hi ... is it possible to put in a connector test that exercises both the happy and not happy paths for this?

I tried running main (without this PR) against against a random gitlab project without a master default branch, but the connector actually appeared to work (https://gitlab.com/snakster/default-branch-test).