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Ignacy Łątka
c0a63875df
Found while reviewing #610 and set aside as out of scope: the code and the prose it comes from are byte-identical at that PR's merge base, and the same mutant survives there too. ## The gap `debugger-status` returns `sourceMapReady: true` as a **hardcoded literal** (`debugger-status.ts:57`). The only thing that makes the literal true is the line above it: ```ts await api.sourceMaps.waitForPending(); ``` and the description sells exactly that: *"sourceMapReady (always true — **waits for pending source maps before returning**; no-op on Chromium)"*. Nothing pins it. Deleting the await: | | existing suite (`test/debugger test/metro test/flows test/utils`) | |---|---| | unmutated | 856 passed | | await deleted | **856 passed** | So a status that reports readiness it never established would ship green. ## Scope, stated honestly This is a test-only change; the shipped behaviour is correct. The impact of a regression is narrow but real: `js-runtime-debugger.ts:214` already drains the registry once while the service is being created, so the await in the tool is what covers maps registered **after** that point - a Fast Refresh, or a lazily loaded bundle chunk. In that window a non-awaiting status would return `sourceMapReady: true` while `SourceMapsRegistry.pendingRegistrations` is non-empty, and a `debugger-inspect-element` issued straight after can miss the file:line it would otherwise resolve. I did not manufacture a user-visible failure end to end, and I am not claiming one - the finding is that the single promised behaviour of this field has no test. ## The tests Both assert the **ordering**, not the literal - a test that only checked `sourceMapReady === true` would pass on the mutant, since the literal is unconditional. 1. `does not resolve until the pending source-map registration settles` - hands the tool a `waitForPending` that returns a deferred promise, drains several macrotask turns, asserts the tool has not returned, then releases it. 2. `reports sourceMapReady only after the wait` - records `["maps-settled", "status-returned"]` and asserts that exact order. | | new tests | |---|---| | on `main` as shipped | 2 passed | | with the await deleted | **2 failed** | eslint `--max-warnings 0`, `tsc --noEmit -p tsconfig.test.json` and prettier all clean.