fix(ci): prefer GitHub Actions PR-event head SHA over GITHUB_SHA

[jd]

On GitHub Actions pull_request builds, GITHUB_SHA points at
the synthetic merge commit GitHub creates by pre-merging the PR
head into the base — not the actual code the tests ran against.
The contributor's real head SHA lives in the event payload at
pull_request.head.sha, and that's the value Mergify dashboards
correlate with. Without this fix, every ci junit-process run
on a PR was uploading the wrong vcs.ref.head.revision resource
attribute.

get_github_actions_head_sha now reads
GITHUB_EVENT_PATH, looks for pull_request.head.sha, and falls
back to GITHUB_SHA if the payload is missing, malformed, or
the build isn't a pull_request event — matching Python's
get_github_actions_head_sha. The PR-event JSON read is shared
across the pull-request-number lookup (existing) and the head-SHA
lookup (new); the number lookup stays strict about parse errors
because it's load-bearing for scopes-send dispatch, while the
SHA lookup stays lenient because GITHUB_SHA is a sane fallback.

Three unit tests pin: payload-wins-over-env, no-PR-field-falls-
back-to-env, and missing-event-file-still-uses-env.

The CircleCI PR-build API fallback Python implements stays
Python-side for now — it requires a GitHub REST API client we
don't have on the Rust side yet.

Co-Authored-By: Claude Opus 4.7 noreply@anthropic.com

Depends-On: #1468

[jd]

This pull request is part of a Mergify stack:

#	Pull Request	Link
1	fix(cli): accept --debug on the Rust binary and actually toggle it in Python	#1464
2	refactor(rust): share test scaffolding via mergify-test-support crate	#1439
3	refactor(core): introduce CommandContext for the queue+freeze prelude	#1441
4	refactor(ci): consolidate the CI-env scrubber into a shared testing module	#1442
5	refactor: drop stale Phase X.Y doc markers and one inline color branch	#1443
6	refactor(tui): share StyledGlyph across queue show/status renderers	#1444
7	refactor(queue): drop indexmap, group_by_scope returns a Vec<(K, V)>	#1445
8	refactor(ci): swap uuid for getrandom in the GHA heredoc delimiter	#1446
9	refactor(config): standardize the workspace on serde_yaml_ng for YAML parsing	#1447
10	test(ci): add live smoke test for ci scopes select-all path	#1460
11	feat(rust): port ci scopes to native Rust	#1461
12	feat(ci): parse JUnit XML reports in native Rust	#1465
13	feat(ci): encode JUnit cases as OTLP and upload to Mergify CI Insights	#1466
14	feat(ci): promote ci junit-process from shim to native Rust	#1467
15	feat(ci): promote ci junit-upload from shim to native as a deprecated alias	#1468
16	fix(ci): prefer GitHub Actions PR-event head SHA over GITHUB_SHA	#1469	👈

[mergify]

Merge Protections

Your pull request matches the following merge protections and will not be merged until they are valid.

🔴 ⛓️ Depends-On Requirements

Waiting for

• depends-on=Mergifyio/mergify-cli#1439 [⛓️ refactor(rust): share test scaffolding via mergify-test-support crate #1439 [stack]]
• depends-on=Mergifyio/mergify-cli#1441 [⛓️ refactor(core): introduce CommandContext for the queue+freeze prelude #1441 [stack]]
• depends-on=Mergifyio/mergify-cli#1442 [⛓️ refactor(ci): consolidate the CI-env scrubber into a shared testing module #1442 [stack]]
• depends-on=Mergifyio/mergify-cli#1443 [⛓️ refactor: drop stale Phase X.Y doc markers and one inline color branch #1443 [stack]]
• depends-on=Mergifyio/mergify-cli#1444 [⛓️ refactor(tui): share StyledGlyph across queue show/status renderers #1444 [stack]]
• depends-on=Mergifyio/mergify-cli#1445 [⛓️ refactor(queue): drop indexmap, group_by_scope returns a Vec<(K, V)> #1445 [stack]]
• depends-on=Mergifyio/mergify-cli#1446 [⛓️ refactor(ci): swap uuid for getrandom in the GHA heredoc delimiter #1446 [stack]]
• depends-on=Mergifyio/mergify-cli#1447 [⛓️ refactor(config): standardize the workspace on serde_yaml_ng for YAML parsing #1447 [stack]]
• depends-on=Mergifyio/mergify-cli#1460 [⛓️ test(ci): add live smoke test for ci scopes select-all path #1460 [stack]]
• depends-on=Mergifyio/mergify-cli#1461 [⛓️ feat(rust): port ci scopes to native Rust #1461 [stack]]
• depends-on=Mergifyio/mergify-cli#1464 [⛓️ fix(cli): accept --debug on the Rust binary and actually toggle it in Python #1464 [stack]]
• depends-on=Mergifyio/mergify-cli#1465 [⛓️ feat(ci): parse JUnit XML reports in native Rust #1465 [stack]]
• depends-on=Mergifyio/mergify-cli#1466 [⛓️ feat(ci): encode JUnit cases as OTLP and upload to Mergify CI Insights #1466 [stack]]
• depends-on=Mergifyio/mergify-cli#1467 [⛓️ feat(ci): promote ci junit-process from shim to native Rust #1467 [stack]]
• depends-on=Mergifyio/mergify-cli#1468 [⛓️ feat(ci): promote ci junit-upload from shim to native as a deprecated alias #1468 [stack]]

This rule is failing.

Requirement based on the presence of Depends-On in the body of the pull request

• depends-on=Mergifyio/mergify-cli#1439 [⛓️ refactor(rust): share test scaffolding via mergify-test-support crate #1439 [stack]]
• depends-on=Mergifyio/mergify-cli#1441 [⛓️ refactor(core): introduce CommandContext for the queue+freeze prelude #1441 [stack]]
• depends-on=Mergifyio/mergify-cli#1442 [⛓️ refactor(ci): consolidate the CI-env scrubber into a shared testing module #1442 [stack]]
• depends-on=Mergifyio/mergify-cli#1443 [⛓️ refactor: drop stale Phase X.Y doc markers and one inline color branch #1443 [stack]]
• depends-on=Mergifyio/mergify-cli#1444 [⛓️ refactor(tui): share StyledGlyph across queue show/status renderers #1444 [stack]]
• depends-on=Mergifyio/mergify-cli#1445 [⛓️ refactor(queue): drop indexmap, group_by_scope returns a Vec<(K, V)> #1445 [stack]]
• depends-on=Mergifyio/mergify-cli#1446 [⛓️ refactor(ci): swap uuid for getrandom in the GHA heredoc delimiter #1446 [stack]]
• depends-on=Mergifyio/mergify-cli#1447 [⛓️ refactor(config): standardize the workspace on serde_yaml_ng for YAML parsing #1447 [stack]]
• depends-on=Mergifyio/mergify-cli#1460 [⛓️ test(ci): add live smoke test for ci scopes select-all path #1460 [stack]]
• depends-on=Mergifyio/mergify-cli#1461 [⛓️ feat(rust): port ci scopes to native Rust #1461 [stack]]
• depends-on=Mergifyio/mergify-cli#1464 [⛓️ fix(cli): accept --debug on the Rust binary and actually toggle it in Python #1464 [stack]]
• depends-on=Mergifyio/mergify-cli#1465 [⛓️ feat(ci): parse JUnit XML reports in native Rust #1465 [stack]]
• depends-on=Mergifyio/mergify-cli#1466 [⛓️ feat(ci): encode JUnit cases as OTLP and upload to Mergify CI Insights #1466 [stack]]
• depends-on=Mergifyio/mergify-cli#1467 [⛓️ feat(ci): promote ci junit-process from shim to native Rust #1467 [stack]]
• depends-on=Mergifyio/mergify-cli#1468 [⛓️ feat(ci): promote ci junit-upload from shim to native as a deprecated alias #1468 [stack]]

🔴 👀 Review Requirements

Waiting for

• #approved-reviews-by>=2

This rule is failing.

• any of:
  • #approved-reviews-by>=2
  • author = dependabot[bot]
  • author = mergify-ci-bot
  • author = renovate[bot]

🔴 🔎 Reviews

Waiting for

• #review-requested = 0

This rule is failing.

• #review-requested = 0
• #changes-requested-reviews-by = 0
• #review-threads-unresolved = 0

🟢 🤖 Continuous Integration

Wonderful, this rule succeeded.

• all of:
  • check-success=ci-gate

🟢 Enforce conventional commit

Wonderful, this rule succeeded.

Make sure that we follow https://www.conventionalcommits.org/en/v1.0.0/

• title ~= ^(fix|feat|docs|style|refactor|perf|test|build|ci|chore|revert|ui)(?:\(.+\))?:

🟢 📕 PR description

Wonderful, this rule succeeded.

• body ~= (?ms:.{48,})

[jd]

Revision history

#	Type	Changes	Reason	Date
1	initial	73d824f		2026-05-27 08:27 UTC
2	rebase	73d824f → 53e9e75 (rebase only)		2026-05-27 08:27 UTC
3	rebase	53e9e75 → eb452fa (rebase only)		2026-05-27 08:46 UTC
4	rebase	eb452fa → ab01533 (rebase only)		2026-05-27 09:00 UTC
5	rebase	ab01533 → dbb0765 (rebase only)		2026-05-27 09:18 UTC
6	rebase	dbb0765 → edcef26 (rebase only)		2026-05-27 10:04 UTC
7	rebase	edcef26 → 1573dd6 (rebase only)		2026-05-27 10:15 UTC