[Bug] [spike] Wrong commit used for core testing

[emmyoop]

Is this a new bug in dbt-common?

• I believe this is a new bug in dbt-common
• I have searched the existing issues, and I could not find an existing issue for this bug

Current Behavior

When we put a PR into the merge queue it uses the wrong commit on dbt_common to run tests against. This is because tox reinstalls all dependencies so overriding the dep isn't working as written.

Expected Behavior

Use the temporary merge commit to run tests to mock the state after merge

Steps To Reproduce

1. Open a Pr
2. Add PR to merge queue
3. observe the commit checked out for dbt-common in PR

Relevant log output

No response

Additional Context

No response

[emmyoop]

I'm not actually sure if this is a problem. See comment in PR for more context. Going to monitor the next real merge to be sure.

[emmyoop]

This is still not working. The commit it shows in CI as the one used on the merge seems to be accurate. However, I just successfully merged a PR with passing core tests that then immediately began failing CI in dbt-core.