Merge Queue & Branch Protection

Strict status checks

"Require branches to be up to date before merging" is the difference between a green check that means something and one that does not.

Without it, a PR can merge on a green run against a base from three days ago — the checks passed against code that no longer exists. With it, the head must be current, so every merge is gated on a run against the real post-merge state.

The cost is rebase churn on busy repositories. That is what merge queues solve.

What a merge queue actually does

The queue builds a speculative merge of your PR on top of the queue ahead of it, runs checks against that combination, and merges only if it passes. This gives strict-check correctness without every author manually rebasing.