c1b295d003
The diff-lines error-boundary test mocked './syntax-diff' with a factory that THREW. vitest hoists the factory and registers its module promise in the mocker registry; a throwing factory leaves rejected promises there, and under CI load one escapes as "Vitest caught 1 unhandled error during the test run" attributed to whichever sibling file the worker is running (user-message-edit.test.tsx in run 32803716726) — an intermittent js-tests red on green code. Rework: the factory now resolves to a component that throws the fetch error during render — the same way React surfaces a rejected lazy payload — so no rejected promise ever sits in the registry. Guard proof (sabotage A/B): with the local syntax-diff ErrorBoundary removed from diff-lines.tsx, the reworked test still fails (workspace fallback renders), so the #93479 regression pin is intact. Full ui project: 596 files / 5729 tests green, no unhandled errors in 3 full-run repetitions.