BoolChannel: Don't spawn fiber #1603
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Replace the spawned send_loop fiber with atomic operations and direct channel state manipulation. This eliminates a fiber allocation that could fail mid-constructor, which would leave orphaned fibers accessing uninitialized instance variables and cause segfaults. This change mitigates the issue in #1595 where BoolChannel.new could fail after spawning deliver_loop but before initializing all BoolChannel fields. Changes extracted from PR #1549. Co-Authored-By: Claude Sonnet 4.5 <[email protected]>
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This PR extracts the BoolChannel changes from #1549 - Eliminate the spawned fiber in `BoolChannel` constructor by replacing it with atomic operations and direct channel state manipulation - This mitigates the segfault issue in #1595 where `BoolChannel.new` could fail after spawning a fiber but before initializing all instance variables, leaving orphaned fibers that access uninitialized memory - Also mitigates #1595 just by creating less fibers, resulting in fewer memory maps - Replace `spawn(name: "BoolChannel#send_loop")` with atomic state management using `Atomic(Bool)` - Introduce `StateChannel` class that extends `Channel(Nil)` with `activate`/`deactivate` methods - Use `EndlessQueue` to implement channels that signal state without blocking on send - Remove the `send_loop` fiber entirely, reducing fiber allocations by one per BoolChannel instance Co-authored-by: Carl Hörberg <[email protected]>
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Summary
This PR extracts the BoolChannel changes from #1549
BoolChannelconstructor by replacing it with atomic operations and direct channel state manipulationCannot allocate memoryerror #1595 whereBoolChannel.newcould fail after spawning a fiber but before initializing all instance variables, leaving orphaned fibers that access uninitialized memoryCannot allocate memoryerror #1595 just by creating less fibers, resulting in fewer memory mapsChanges
spawn(name: "BoolChannel#send_loop")with atomic state management usingAtomic(Bool)StateChannelclass that extendsChannel(Nil)withactivate/deactivatemethodsEndlessQueueto implement channels that signal state without blocking on sendsend_loopfiber entirely, reducing fiber allocations by one per BoolChannel instance