CI_MERGE_REQUEST_DIFF_BASE_SHA is not set when MR doesn't contain any commits

Everyone can contribute. Help move this issue forward while earning points, leveling up and collecting rewards.

• Close this issue

Summary

If MR doesn't contain any commits and CI runs, CI_MERGE_REQUEST_DIFF_BASE_SHA is not set, despite the documentation saying:

These variables are available when:

• The pipelines are merge request pipelines.
• The merge request is open.

| CI_MERGE_REQUEST_DIFF_BASE_SHA | 13.7 | all | The base SHA of the merge request diff. |

Steps to reproduce

1. Create a CI pipeline that uses or displays CI_MERGE_REQUEST_DIFF_BASE_SHA
2. Create an empty MR that runs CI (this is disabled by default, so bug #219583 (closed) can be used
3. Check CI job to see how CI_MERGE_REQUEST_DIFF_BASE_SHA is used or displayed

Example Project

Woodz1/gitlab-bug-repros!2

What is the current bug behavior?

CI_MERGE_REQUEST_DIFF_BASE_SHA is not set

What is the expected correct behavior?

CI_MERGE_REQUEST_DIFF_BASE_SHA is set to the base commit for this MR

Relevant logs and/or screenshots

https://gitlab.com/Woodz1/gitlab-bug-repros/-/jobs/3067742250

Output of checks

This bug happens on GitLab.com

Results of GitLab environment info

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

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