fix(settings): set squash-merge default message to blank - #519
Merged
Conversation
…github squash_merge_commit_message=COMMIT_MESSAGES (GitHub's default) aggregates every squashed commit's message, trailers included, into the merge commit whenever --body is omitted -- the actual mechanism behind the Co-authored-by trailer that reappeared on both #516 and #517 in one day. A pre-merge commit-lint check cannot catch this: the trailer is synthesized into a commit that does not exist until merge time. Sets squash_merge_commit_title=PR_TITLE and squash_merge_commit_message=BLANK via the repos API so there is nothing to synthesize a trailer from, regardless of --body. Adds the setting and its rationale to decisions/0013-repository-settings-baseline.md. Org-wide audit/rollout tracked in #518.
ss-o
added
type:maintenance
This was referenced Aug 16, 2026
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Summary
Documents and applies the actual fix for the
Co-authored-bytrailer that reappeared on both #516 and #517 (same day, the latter being the PR that added CI enforcement against it — which structurally can't catch this, since GitHub synthesizes the trailer into a commit that doesn't exist until merge time).Root cause
squash_merge_commit_message: COMMIT_MESSAGES(GitHub's default) aggregates every squashed commit's full message — trailers included — into the merge commit whenever a squash merge runs without an explicit--body.Fix (already applied to this repo via API, this PR documents it)
Squash merges now default to the PR title only, no body — nothing left to synthesize a trailer from.
Change
Adds a row + rationale to
decisions/0013-repository-settings-baseline.md's settings baseline table, required uniformly across all classes (it's a plain repo API setting, not a ruleset, so it isn't class-scaled).Scope
z-shell/.githubonly. Org-wide audit/rollout tracked in #518.Refs #518