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Observing the same entry type more than once on a PerformanceObserver,
through repeated `observe({ type })` calls or duplicates in
`entryTypes`, incremented the internal observer count each time, while
`disconnect()` decremented it only once per observed type. The counts
never returned to zero, so GC tracking stayed installed, and entries
for types such as `'http'` and `'dns'` kept being created after all
observers had disconnected.
Count each entry type at most once per observer.
Assisted-by: OpenCode
Signed-off-by: James M Snell <jasnell@gmail.com>
Whether the V8 GC callbacks used for `'gc'` performance entries were installed was tracked by a boolean in JavaScript, separately from the native state, and the two could get out of sync. After deserializing a user-land snapshot built while a `'gc'` PerformanceObserver was active, the boolean claimed the callbacks were installed, although V8 GC callbacks do not survive a snapshot. Observing `'gc'` again did not install them, and disconnecting removed callbacks that had never been registered, crashing the process. Track the installation state in `PerformanceState` instead, and replace the install and remove bindings with a single idempotent `updateGarbageCollectionTracking()` binding, which registers the callbacks if and only if there are `'gc'` observers. Assisted-by: OpenCode Signed-off-by: James M Snell <jasnell@gmail.com>
V8 GC callbacks do not survive a snapshot, so a `'gc'` PerformanceObserver that was active while building a user-land snapshot received no entries after deserialization, unless another `'gc'` observer was created. When `'gc'` is observed while building a snapshot, add a deserialize callback that registers the GC callbacks again if `'gc'` observers are still active. Assisted-by: OpenCode Signed-off-by: James M Snell <jasnell@gmail.com>
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PerformanceObservercounts could get out of sync. GC callback handling, in particular, could get out of sync when serializing/deserializing a snapshot, leading to a segfault.