Add a missing protocol conformance to ClientTransport #4
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simonjbeaumont
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May 12, 2023
simonjbeaumont
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Jan 16, 2024
…#46) ### Motivation When running the cancellation tests in a loop, very occasionally there would be a crash with the following backtrace: ``` #0 0x000000018aa008d4 in objc_opt_respondsToSelector () #1 0x000000018aea3410 in _outputStreamCallbackFunc () #2 0x000000018aea3310 in _signalEventSync () #3 0x000000018aeecdb0 in ___signalEventQueue_block_invoke () #4 0x000000018abe6cb8 in _dispatch_call_block_and_release () #5 0x000000018abe8910 in _dispatch_client_callout () #6 0x000000018abefea4 in _dispatch_lane_serial_drain () #7 0x000000018abf0a08 in _dispatch_lane_invoke () #8 0x000000018abfb61c in _dispatch_root_queue_drain_deferred_wlh () #9 0x000000018abfae90 in _dispatch_workloop_worker_thread () #10 0x000000018ad96114 in _pthread_wqthread () ``` This seems to indicate that the output stream is trying to access its delegate. However, when running with debug logging enabled I can see that the delegate has already been deinitialized. This is likely a result of the delegate itself owning the stream and setting the stream delegate to `self`, which IIUC is an established pattern. This presents a race in teardown. ### Modifications This patch sets the output stream delegate to `nil` in the delegate `deinit`. ### Result No attempts to call the delegate will happen after it is has been deinitailzed. ### Test Plan With this patch, the failing test passes when run an order of magnitude more times than were required to reliably reproduce the crash without the patch.
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Motivation
We lost URLSessionTransport's conformance to ClientTransport along the way somewhere. But that's kind of its main job :)
Modifications
Re-add the conformance.
Result
Now the transport can be used as a ClientTransport again.
Test Plan
Explicitly cast the test transport to be a ClientTransport, rather than using the concrete type.