Test: keep React 19 coverage out of the React 18 lane

[justin808]

Why

The post-merge audit of #4622 reproduced one React 18 regression in the repaired Jest suite selection. registerServerComponent.client.test.jsx requires React.use, but the file had been moved into test:non-rsc, which is the package's React-18-compatible lane. With React 18.3.1 it failed during module loading before the test's Node guard could run.

This is a bounded closeout correction for #4622 and #4565.

What changed

• Keep registerServerComponent.client.test.jsx out of test:non-rsc.
• Run it in the existing React-19-gated client/streaming suite.
• Extend the suite-selection checker so a declared React-19-only client test cannot drift back into test:non-rsc while still passing the ordinary orphan check.

Verification

• Reproduced against a real React 18.3.1 + React DOM 18.3.1 install: of the five tests newly selected by Restore complete Pro Jest suite selection #4622, four passed and registerServerComponent.client.test.jsx failed at module load with React.use is not defined.
• After the fix, React 18 test:non-rsc --listTests excludes that file and test:streaming exits through the React-19 version guard.
• Full Pro package test command: 48/48 files selected; 35 non-RSC suites (454 tests), 6 client/streaming suites (140 tests), and 7 server-RSC suites (23 tests) passed.
• Suite-selection unit tests: 3/3 passed.
• TypeScript type-check, ESLint, Prettier, diff checks, and all 854 Pro license headers passed.
• Independent bounded review: clean; 48 unique selections with no missing or duplicate-routed target.

No changelog entry: this only corrects maintainer test routing and does not change shipped runtime behavior.

Summary by CodeRabbit

• Tests
  • Updated test suite selection so React 19-only client tests run with the streaming suite and are excluded from the non-RSC suite.
  • Added validation to detect incorrect test-suite assignments and prevent uncovered tests.

[justin808]

+ci-status

[justin808]

+ci-run-hosted

[github-actions]

CI Status

Head SHA: c4cbb9aff888
Changed files: 3
Docs-only heuristic (matches ci-changes-detector metadata paths): no
ready-for-hosted-ci label: absent
force-full-hosted-ci label: absent
Current hosted-CI waiver: not present for this SHA

Only the required gate is active unless hosted CI is requested.

[github-actions]

Hosted CI Requested

Triggered 9 workflow(s) for c4cbb9aff888.
Mode: optimized hosted CI (path-selected by script/ci-changes-detector).
Added ready-for-hosted-ci, so future commits will keep running optimized hosted CI until +ci-stop-hosted is used.

View progress in the Actions tab.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 0d044af2-68cd-4527-b3fb-863762b1d3fe

📥 Commits

Reviewing files that changed from the base of the PR and between 670e1b3 and c4cbb9a.

📒 Files selected for processing (3)

• packages/react-on-rails-pro/package.json
• packages/react-on-rails-pro/scripts/check-jest-suite-selection.mjs
• packages/react-on-rails-pro/scripts/check-jest-suite-selection.test.mjs

---

Walkthrough

The Jest scripts now route the React 19-only client test through the streaming suite instead of the non-RSC suite. Suite-selection validation separately tracks both suites and tests that invalid React 19 test selection raises an error.

Changes

Jest suite selection

Layer / File(s)	Summary
Update Jest suite wiring packages/react-on-rails-pro/package.json	The non-RSC Jest command excludes registerServerComponent tests, while the streaming command includes the React 19-only client test.
Validate React 19 test placement packages/react-on-rails-pro/scripts/check-jest-suite-selection.mjs, packages/react-on-rails-pro/scripts/check-jest-suite-selection.test.mjs	Suite outputs are collected separately, React 19-only tests are rejected from test:non-rsc, and the rejection is covered by a test.

Estimated code review effort: 2 (Simple) | ~10 minutes

Possibly related PRs

• shakacode/react_on_rails#4549: Adjusts related test:non-rsc ignore patterns for RSC-named client tests.
• shakacode/react_on_rails#4622: Modifies the suite-selection script and related registerServerComponent test wiring.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly matches the main change: keeping React 19-only test coverage out of the React 18 test lane.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/4565-react18-jest-selection

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[greptile-apps]

Greptile Summary

This PR updates the Pro Jest suite routing for a React 19-only client test. The main changes are:

• Excludes registerServerComponent tests from test:non-rsc.
• Adds registerServerComponent.client.test.jsx to test:streaming.
• Adds a suite-selection check for React 19-only client tests in the React 18 lane.
• Adds unit coverage for the new suite-selection guard.

Confidence Score: 4/5

The changed test routing needs a fix for the client test environment before merging.

• The new streaming selection can run a DOM-dependent client test in a Node-default lane.
• The suite-selection guard is useful, but exact path matching leaves a small routing gap on canonicalized paths.

packages/react-on-rails-pro/package.json; packages/react-on-rails-pro/scripts/check-jest-suite-selection.mjs

Important Files Changed

Filename	Overview
packages/react-on-rails-pro/package.json	Moves a React 19-only client test out of test:non-rsc and into test:streaming, but the selected lane may not provide the DOM environment that test uses.
packages/react-on-rails-pro/scripts/check-jest-suite-selection.mjs	Adds a guard against React 19-only client tests in test:non-rsc, with an exact path comparison that can miss canonicalization differences.
packages/react-on-rails-pro/scripts/check-jest-suite-selection.test.mjs	Adds unit coverage for the new React 19-only client test guard.

_{Reviews (1): Last reviewed commit: "Keep React 19 tests out of the React 18 ..." | Re-trigger Greptile}

[claude]

Review

Overview: This is a bounded, well-targeted follow-up to #4622. It moves registerServerComponent.client.test.jsx from the React-18-compatible test:non-rsc Jest lane into the React-19-gated test:streaming lane, and adds a regression check in check-jest-suite-selection.mjs so a declared React-19-only client test can't silently drift back into test:non-rsc.

Correctness

• Root cause tracked down correctly: the test file's describe/it blocks are guarded by getNodeVersion() >= 18, but the failure under React 18.3.1 happens at module import time (React.use is not defined), before that guard ever runs — so the Node-version guard inside the test can't prevent it. Routing the file through test:streaming, which is protected by check-react-version.cjs exiting early (process.exit(0)) before jest ever loads the file under React < 19, is the right fix.
• The added test:non-rsc regex exclusion (|registerServerComponent) is a substring match rather than an exact filename match, consistent with the existing exclusions in that same regex (e.g. streamServerRenderedReactComponent). I checked — there's currently only one file matching *registerServerComponent* in tests/, so no unintended exclusions today, but worth keeping in mind if a registerServerComponent.server.test.jsx-style file is ever added later, since it would silently be swept into the same exclusion.
• The new misplacedReact19Tests check in check-jest-suite-selection.mjs only executes when the checker itself runs under React 19 (the function returns early for React < 19, per the existing top-of-function guard). That's fine given this is a static lane-membership check based on --listTests output (which doesn't depend on the installed React version for pattern matching), but it's worth being explicit that this guard doesn't protect a hypothetical CI lane that runs the suite-selection checker under React 18 — it relies on the checker consistently running under React 19 in CI.

Test coverage: The new unit test (check-jest-suite-selection.test.mjs) correctly exercises the new throw path by mocking runPnpm so test:non-rsc's listed tests include the React-19-only file, verifying the thrown error message. Good, focused test.

Style/maintenance: react19OnlyClientTests is a manually maintained array with a single hardcoded entry. That's reasonable for now given there's only one such file, but as a maintenance note, this list will need to be updated by hand if more React-19-only client tests are added to tests/streaming-style suites in the future — nothing to change here, just flagging for awareness.

Risk: Low. Scope is limited to test routing/tooling, no runtime/shipped code is touched, and the "no changelog entry" call is correct per this repo's changelog guidelines (test-only changes are excluded).

No blocking issues found.

[github-actions]

size-limit report 📦

Path	Size
react-on-rails/client bundled (gzip)	63.51 KB (0%)
react-on-rails/client bundled (gzip) (time)	63.51 KB (0%)
react-on-rails/client bundled (brotli)	54.46 KB (0%)
react-on-rails/client bundled (brotli) (time)	54.46 KB (0%)
react-on-rails-pro/client bundled (gzip)	64.87 KB (0%)
react-on-rails-pro/client bundled (gzip) (time)	64.87 KB (0%)
react-on-rails-pro/client bundled (brotli)	55.81 KB (0%)
react-on-rails-pro/client bundled (brotli) (time)	55.81 KB (0%)
registerServerComponent/client bundled (gzip)	135.37 KB (0%)
registerServerComponent/client bundled (gzip) (time)	135.37 KB (0%)
registerServerComponent/client bundled (brotli)	81.66 KB (0%)
registerServerComponent/client bundled (brotli) (time)	81.66 KB (0%)
wrapServerComponentRenderer/client bundled (gzip)	127.84 KB (0%)
wrapServerComponentRenderer/client bundled (gzip) (time)	127.84 KB (0%)
wrapServerComponentRenderer/client bundled (brotli)	74.96 KB (0%)
wrapServerComponentRenderer/client bundled (brotli) (time)	74.96 KB (0%)

[justin808]

Review disposition — head c4cbb9aff888

• Must-fix: none.
• Discuss: none.
• False positives resolved: 2 Greptile threads.
  • The client/streaming lane inherits jsdom; the exact lane passed 6 suites / 140 tests including the DOM-dependent test.
  • All suite paths come from the same Jest package root/config; the checker observed 48 total and 48 unique selections, with the React-19-only target only in the gated lane.
• Clean reviews: Claude and CodeRabbit.
• Candidate changes after review: none.

Current-head validation remains: full Pro Jest 48 files / 617 tests plus 3 suite-selection tests, real React 18.3.1 routing replay, type-check, ESLint, Prettier, diff checks, and 854 Pro headers.

[justin808]

Completed-batch post-merge audit — PASS

• Final exact range: acbd7333bc4cf95b295d79d321360ea31dd143b8..a8cd53f36dbdf4458b4b75885b9ac96e2e42fb5f.
• Scope: original PRs Pro: add an authorization hook for RSC payloads #4621–Require graph-derived RSC client references in Doctor #4625 plus corrective PR Test: keep React 19 coverage out of the React 18 lane #4635; the first-parent range contains exactly these six squash merges.
• Independent checker: gpt-5.6-sol/high, read-only and exact-range bounded.
• Result: no findings. The prior React-18 Jest-routing P2 is resolved by Test: keep React 19 coverage out of the React 18 lane #4635 and composes without overlap conflicts with the other five PRs.
• Live closeout: every PR merged, every original issue closed, zero pending/failed checks, zero unresolved review threads, and batch QA evidence replays as SATISFIED.

No follow-up remains.