STAC-25458: run the CI workflows on merge_group - #496
Merged
LouisParkin merged 1 commit intoAug 25, 2026
Conversation
Prerequisite for enabling a merge queue on the default branch. The queue requires the three 'CI success (...)' roll-up checks to report on the speculative merge commit, so the workflows have to listen on merge_group before the ruleset is created. Enabling the queue first would leave every queued PR waiting on checks that never start until it is ejected. The trigger is inert until a queue exists, so this is safe to merge on its own. No publishing runs on merge_group: every publish, sign and Cerberus job is already gated on event_name == 'push', as is the await-verification barrier. The fork guards are spelled event_name != 'pull_request', which is true for merge_group, so the build and test jobs do run in the queue - which is the point. Cache saves are excluded from merge_group. Actions caches written from a merge_group run are scoped to the throwaway gh-readonly-queue ref, so they could never be restored by a later build; only the ~270MB per arch of storage churn would be real. Restores are left ungated, so queue runs still read the default branch caches. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
LouisLotter
approved these changes
Aug 25, 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
2 participants
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Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be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.
Adds a
merge_group:trigger to the three CI workflows, as the prerequisite for enabling a merge queue on the default branch.The queue requires the
CI success (...)checks to report on the speculative merge commit, so the workflows must listen onmerge_groupbefore the ruleset is created — otherwise every queued PR waits on checks that never start. The trigger is inert until a queue exists, so this is safe to merge on its own.Nothing publishes from the queue: publish, sign, Cerberus and the await-verification barrier are all already gated on
event_name == 'push'. Cache saves are excluded frommerge_groupbecause caches written there are scoped to the throwawaygh-readonly-queueref and could never be restored; restores stay ungated so queue runs still read the default-branch caches.Validation: all three workflows parse, Zizmor 1.29.0 clean (no findings).
Ref STAC-25458.