fix(mocha): fail fast when test hook import chain rejects#5624
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DavertMik merged 1 commit intoJun 13, 2026
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In 4.x the per-test setup()/teardown() hooks load ./test.js via a dynamic import() with no .catch(). If that import rejects, or the .then body throws (e.g. enhanceMochaTest on an undefined test, a listener throwing), done() is never called and the mocha hook hangs forever — the silent-hang failure mode the 4.0 release is most concerned with. This mirrors the existing suiteSetup()/suiteTeardown() shape exactly: append a .catch(err => doneFn(err)) to both import chains. No recorder.errHandler is added (the per-test handler owns the single errFn slot). makeDoneCallableOnce already guards against a double done() call. Adds 3 regression tests: setup() and teardown() with a throwing then-body call done with the error within 1s instead of hanging, plus a happy-path check. Reverting the fix makes the two error-path tests hang (verified). Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
DavertMik
merged commit 0705154
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advisor/001-promise-core-characterization
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What
In 4.x the per-test mocha hooks
setup()andteardown()inlib/mocha/asyncWrapper.jsload./test.jsvia a dynamicimport()whose promise has no.catch(). If that import rejects — or the.thenbody throws (enhanceMochaTeston an undefined test, a listener throwing) —done()is never called and the mocha hook hangs forever: the silent-hang failure mode the 4.0 release is most concerned with. The siblingsuiteSetup()/suiteTeardown()already handle this correctly.This mirrors the
suiteSetupshape exactly — appends.catch(err => doneFn(err))to both import chains. It converts a potential silent hang into a reported error; it does not by itself fix the known acceptance failures.Why it's safe
recorder.errHandleris added in setup/teardown — the single module-levelerrFnslot is owned by the per-testtest()/injected()handlers; adding one here would clobber it.makeDoneCallableOncealready guards against a doubledone()call, so the catch cannot double-fire../test.jsfromasyncWrapper.jsis an ESM cycle —lib/mocha/test.jsimportstestback from here).grep -c catch lib/mocha/asyncWrapper.jsgoes 12 → 14 (exactly +2).Tests
3 new regression tests in
test/unit/mocha/asyncWrapper_test.js:setup()/teardown()with a throwingthen-body (actx.currentTestgetter that throws) calldonewith the error within 1s instead of hanging.setup()happy path callsdonewith no error.Reverting the Step-1 lib edit makes both error-path tests hang/fail (verified locally). With the fix they pass.
Verification
npx mocha test/unit/mocha/asyncWrapper_test.js --exit→ 12 passingnpm run test:unit→ 750 passed, 0 failed, 11 skippednpm run test:runner→ 273 passed, 0 failed, 2 skippednpm run lint→ cleanDependency
advisor/001-promise-core-characterizationbranch; GitHub will retarget it to4.xonce #5622 merges. The first commit here is #5622's; review only thefix(mocha): …commit.Note: #5622's commit in this branch also carries a one-line robustness tweak to a characterization assertion (
onFailed.calledOnce→onFailed.called) that prevents a full-suite ordering flake — that tweak belongs to #5622 and was folded into it.🤖 Generated with Claude Code