Merge a branch into main

I need to merge feature/auth into main for tomorrow's deploy. Merge the branch feature/auth into local main, but first verify main is up to date with origin/main and that feature/auth has no failing tests. If merge conflicts appear, stop and list the conflicting files. After a clean merge, run the test suite and report failures before proceeding to push.

Before merging feature/auth into main, make the candidate easy to approve for the release manager. Pull together a short summary of what feature/auth changes, show the risk areas (authentication, sessions, migrations), surface any database migration or API contract changes up top, and list what to run locally to validate the merge quickly.

I merged feature/auth into main locally and now the test suite fails in modules unrelated to auth. The CI passed on the feature branch before merge. I worry the merge brought in a hidden change or a flaky test. I cannot tell which. Diagnose the likely causes and recommend the best next steps to isolate whether this is a merge regression, a flaky test, or environment drift.

Over multiple releases, merges into main frequently introduce regressions or unexpected failures that break my team's deployments. I want to stop firefighting and reduce these surprises. Identify the habitual mistakes that cause this and propose one practical change to our merge process that will reduce regressions without adding much overhead.