The CDP server ran every connection's pages on one LocalSet thread, so two
pages' V8 isolates shared an OS thread. Under concurrent navigation a cancelled
event-loop future could leave one isolate entered while another page's
execute_script ran, tripping V8's heap->isolate() == Isolate::TryGetCurrent()
check and aborting the process (#430). No single-thread serialization fixes
this reliably: the cancellation-leak pattern is pervasive and partly inside
deno_core.
Give each WebSocket connection its own OS thread with its own current_thread
runtime, LocalSet, and CdpContext, so every page's isolate is confined to one
thread. V8's invariant is per-thread, so two connections' isolates can never
collide. This is the "Option 2" fix named in obscura-js/src/v8_lock.rs, and it
also lets connections run in parallel instead of serializing on one thread.
- CdpContext::new_with_shared_context reuses one Arc<BrowserContext> across all
connections, so they share one cookie jar and one HTTP client.
- A single signal watcher flips the accept flag and wakes every connection's
processor via notify_waiters(); the accept side persists cookies once on
shutdown.
- Serialize isolate construction with a process-wide lock: the leaptiering
JSDispatchTable setup is not safe to run from several threads at once.
- Warm up V8 once on the main thread before any connection thread creates an
isolate; creating the first isolate off the main thread segfaults in
InitializeBuiltinJSDispatchTable.
obstacle course 33/33, obscura-cdp 75/75 including the concurrent-navigation and
control-plane tests. Concurrency 2 and 4 against heavy pages no longer abort.
Fixes#430.
sycatle
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