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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"oracle-gaps: refuse at baseline when more than one Vitest copy is loaded","articleBody":"Reported from an adopter's first session, at c58b0c2. Not yet reproduced here.\n\n**Problem.** pnpm installed vitest@4.1.12 twice, once for each `@types/node` peer. The runner used one copy, while `@tanstack/oracles` and the oracle file shared the other. So `useOracleClock`'s `vi.useFakeTimers` and the driver's `vi.advanceTimersByTime` ran on different copies, and the run failed with \"A function to advance timers was called but the timers APIs are not mocked\". The driver records thrown errors as observations, so the baseline reported the failure as a law violation (visible order, at checkpoint `error`). It took a replay to see that the setup was the cause.\n\n**Proposal.** The baseline should refuse, with a fix line, when more than one vitest instance is loaded. One way to check: compare the resolved vitest path from the harness, from the framework, and from the test file. This is a harness failure, so it should stop the run and not be charged to a mutant (cleanup plan, Phase 2 A2).\n\nThis issue was written by Isaac.\n","author":{"url":"https://github.com/KyleAMathews","@type":"Person","name":"KyleAMathews"},"datePublished":"2026-11-13T21:25:18Z","url":"https://github.com/TanStack/oracles/issues/66"}