fix(gh): fix re-run button on Pull Requests by chmouel · Pull Request #2597 · tektoncd/pipelines-as-code

chmouel · 2026-03-19T13:51:52Z

📝 Description of the Change

GitHub check_run and check_suite rerequests for fork PRs can have
a null head_branch and an empty pull_requests list. PAC was falling
back to treating these events as push events, causing the Re-run
button on PRs to have no effect.

When head_branch is null, fall back to looking up the associated PR
by commit SHA before deciding the event type. If a PR is found,
process as a PR rerequest. If not, return a clear error.

output.mp4

🔗 Linked Issue

Jira https://redhat.atlassian.net/browse/SRVKP-11161

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✅ Submitter Checklist

chmouel · 2026-03-19T14:42:14Z

/gemini review

Copilot

Pull request overview

This PR fixes GitHub check_run / check_suite “rerequested” handling for fork PRs where the webhook payload can have head_branch: null and an empty pull_requests list, by falling back to resolving the PR via commit SHA instead of misclassifying the event as a push.

Changes:

Update GitHub payload parsing to resolve PR rerequests by commit SHA when head_branch is missing.
Add unit tests covering the new SHA-resolution behavior and the error case when no PR is found.
Extend the GitHub GHE e2e rerequest test to exercise the null-head_branch check_run scenario; add a new JSON fixture.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 5 comments.

File	Description
`pkg/provider/github/parse_payload.go`	Adds SHA-based PR lookup fallback for rerequest events when `head_branch` is missing.
`pkg/provider/github/parse_payload_test.go`	Adds unit tests for null-`head_branch` rerequest behavior (success + failure).
`test/github_pullrequest_rerequest_test.go`	Adds an e2e scenario sending a `check_run` rerequest with null `head_branch` and empty PR list.
`test/fixtures/check_suite_rerequest_null_branch.json`	Adds a fixture representing a null-`head_branch` check_suite/check_run rerequest payload.

Comments suppressed due to low confidence (1)

pkg/provider/github/parse_payload.go:495

In the check_run rerequest fallback where this is treated as a push event, runevent.TriggerTarget is never set (unlike handleCheckSuites, which sets it to "push"). Downstream logic (e.g., changed-files fetching/switches on TriggerTarget) may treat an empty TriggerTarget as unknown and skip important behavior. Set runevent.TriggerTarget = triggertype.Push (or "push") alongside runevent.EventType = "push" for consistency.

		runevent.BaseBranch = runevent.HeadBranch
		runevent.BaseURL = runevent.HeadURL
		runevent.EventType = "push"
		// we allow the rerequest user here, not the push user, i guess it's
		// fine because you can't do a rereq without being a github owner?
		runevent.Sender = event.GetSender().GetLogin()
		v.userType = event.GetSender().GetType()
		return runevent, nil

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pkg/provider/github/parse_payload.go

test/fixtures/check_suite_rerequest_null_branch.json

chmouel · 2026-03-19T16:52:47Z

Review from Gemini Code

I've taken a deep look at this pull request. Here is my assessment:

The Problem:
GitHub's check_run and check_suite rerequested webhook payloads occasionally arrive with a null head_branch, particularly when triggered from the UI for pull requests without a full suite context. This caused the provider payload parser to either error out or incorrectly assume a push event when it shouldn't.

The Fix:
The introduced changes in pkg/provider/github/parse_payload.go correctly intercept cases where HeadBranch is empty and SHA is present. By falling back to getPullRequestsWithCommit, the code resolves the associated pull request directly via the GitHub API, reconstructing the missing context before continuing with v.getPullRequest(ctx, runevent). This is a clean and robust fallback.

Testing:

Unit Tests: Excellent additions in pkg/provider/github/parse_payload_test.go covering both check_run and check_suite scenarios where HeadBranch is null.
E2E Tests: A new test case in test/github_pullrequest_rerequest_test.go specifically verifies the "null head_branch" scenario dynamically, which is great for catching future regressions.
Test Fixtures: test/fixtures/check_suite_rerequest_null_branch.json correctly models the problematic webhook payload.

Conclusion:
The logic handles the edge case gracefully. The error handling is solid (failing fast if no PR is found). The tests are comprehensive. This looks good to merge. LGTM! 🚀

chmouel · 2026-03-20T15:17:29Z

/test linters

chmouel · 2026-03-20T15:18:07Z

/cancel linters

chmouel · 2026-03-20T15:23:11Z

/retest

pkg/provider/github/parse_payload.go

chmouel · 2026-03-31T11:47:18Z

@zakisk I updated the fix based on your review.

For the null head_branch rerequest path, we now resolve PRs by commit SHA, filter the results to open PRs, and only continue if there is exactly one open match. If there are multiple open PRs associated with the same commit, we return an explicit error instead of picking prs[0], since the webhook payload does not tell us which PR the UI rerun came from.

I also removed the extra getPullRequest() round-trip in that fallback path. Once ListPullRequestsWithCommit gives us the PR, we now reuse that object to populate the run event directly instead of fetching the PR again.

here is my recording of my test:

recording-20260331-14h04.mp4

zakisk · 2026-04-02T07:21:20Z

we now resolve PRs by commit SHA, filter the results to open PRs, and only continue if there is exactly one open match. If there are multiple open PRs associated with the same commit, we return an explicit error instead of picking prs[0], since the webhook payload does not tell us which PR the UI rerun came from.

@chmouel this looks good to me but may be document this behavior then?
https://pipelinesascode.com/docs/guides/running-pipelines/#github-apps

GitHub check_run and check_suite rerequests for fork PRs can have a null head_branch and an empty pull_requests list. PAC was falling back to treating these events as push events, causing the Re-run button on PRs to have no effect. When head_branch is null, fall back to looking up the associated PR by commit SHA before deciding the event type. If a PR is found, process as a PR rerequest. If not, return a clear error. Signed-off-by: Chmouel Boudjnah <chmouel@redhat.com>

codecov-commenter · 2026-04-02T09:27:20Z

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Codecov Report

❌ Patch coverage is 89.09091% with 6 lines in your changes missing coverage. Please review.
✅ Project coverage is 58.73%. Comparing base (eff5928) to head (375cb58).
⚠️ Report is 62 commits behind head on main.

Files with missing lines	Patch %	Lines
pkg/provider/github/parse_payload.go	88.46%	4 Missing and 2 partials ⚠️
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Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2597      +/-   ##
==========================================
+ Coverage   58.47%   58.73%   +0.25%     
==========================================
  Files         205      206       +1     
  Lines       19625    20296     +671     
==========================================
+ Hits        11476    11920     +444     
- Misses       7434     7611     +177     
- Partials      715      765      +50

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chmouel · 2026-04-02T09:40:55Z

@chmouel this looks good to me but may be document this behavior then?
pipelinesascode.com/docs/guides/running-pipelines#github-apps

i think that's a bit too low level to document? that and i don't imagine a lot of peolple have PR with multiple related commit that is not merged on HEAD (it usually a rebase so it would not see it as first)

chmouel requested a review from Copilot March 19, 2026 14:42

Copilot AI reviewed Mar 19, 2026

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chmouel force-pushed the fix-gh-fix-re-run-button-on-pull-requests branch from 98e1889 to 7c8d958 Compare March 20, 2026 08:11

zakisk reviewed Mar 25, 2026

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chmouel mentioned this pull request Mar 26, 2026

Automated release for tektoncd projects tektoncd/plumbing#58

Open

chmouel force-pushed the fix-gh-fix-re-run-button-on-pull-requests branch from 7c8d958 to 0217de3 Compare March 31, 2026 11:51

tekton-robot added the needs-rebase label Mar 31, 2026

chmouel force-pushed the fix-gh-fix-re-run-button-on-pull-requests branch from 0217de3 to 38df0c5 Compare March 31, 2026 11:55

tekton-robot removed the needs-rebase label Mar 31, 2026

chmouel force-pushed the fix-gh-fix-re-run-button-on-pull-requests branch from 38df0c5 to 04e597b Compare April 1, 2026 12:03

tekton-robot added the needs-rebase label Apr 1, 2026

chmouel force-pushed the fix-gh-fix-re-run-button-on-pull-requests branch from 322557a to 618af76 Compare April 1, 2026 18:00

tekton-robot removed the needs-rebase label Apr 1, 2026

theakshaypant approved these changes Apr 2, 2026

View reviewed changes

chmouel force-pushed the fix-gh-fix-re-run-button-on-pull-requests branch from c025f1f to 375cb58 Compare April 2, 2026 09:24

chmouel merged commit bdcbf41 into tektoncd:main Apr 2, 2026
13 checks passed

chmouel deleted the fix-gh-fix-re-run-button-on-pull-requests branch April 2, 2026 09:57

theakshaypant mentioned this pull request Apr 9, 2026

Rerun in github app is not working #1368

Closed

chmouel linked an issue Apr 9, 2026 that may be closed by this pull request

Rerun in github app is not working #1368

Closed

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📝 Description of the Change

🔗 Linked Issue

🧪 Testing Strategy

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chmouel commented Mar 19, 2026

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