Leaving a multiplayer game froze the app for good. Closing a link closed
the BufferedReader first, and BufferedReader.close() wants the very lock
readLine() holds for the whole of a blocking read — a read that only
closing the socket underneath it can ever end, which is the step the
close never reached. Both callers run on the thread drawing the screen
(AppRoot.pop and PlayScreen's onDispose), so the main thread waited on
itself and the app stopped responding. runCatching was no help: nothing
was thrown, it simply never came back.
StreamConnection.close() now closes only the raw streams, which is what
actually ends the read; the reader coroutine then closes its own wrapper
on its own thread, where it owns the lock. Leaving takes single-digit
milliseconds instead of never returning.
It bit chess because chess is the one game here worth leaving in the
middle of. A card hand is over in minutes; a game of chess between two
people who have had enough of it has no natural end, and there was
nothing to end it with, so:
- Chess has an End game action, with a confirmation, so a table can be
walked away from without hunting for a way out.
- A link that drops on its own now reports itself on the same channel
as everything else, so the device still at the table is told the
other player has left rather than waiting on a move that is not
coming. Bye was in the protocol and never sent; nothing needed to
change on the wire for this.
- Leaving a table no longer lands back in the lobby that started it. A
lobby starts advertising the moment it is drawn, so "leave the game"
used to put the player straight into another one.
Two crashes of the same shape on the same path, both in coroutines
launched in the screen's own scope where nothing catches anything:
- The host's AI applied a move chosen before it took the lock, checking
only that the seat had not changed. applyMove throws on a move that
is no longer legal. Harmless while an AI answered instantly, which
stopped being true when the chess search moved off-thread and started
taking seconds. It is now checked against the position as it stands,
and a stale choice is made again rather than forced.
- A table the rules reject, or a state a client cannot decode, took the
app down. Both are now reported.
Covered by MatchControllerNetworkTest, which plays a game over a real
socket pair and leaves it from either end. The leaving test runs on a
daemon thread and asserts it returns, so a regression fails the build
rather than hanging it — verified by reinstating the old close(), which
hangs the suite until it is killed.
Claude
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