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v0.12.0 — Non-Blocking I/O & Concurrency Fixes

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@dweekly dweekly released this 11 Feb 03:22
· 201 commits to main since this release
v0.12.0
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Non-Blocking I/O Modernization

Traceroute I/O: poll(2) replaced with DispatchSourceRead

  • TraceReceiveOperation and StreamingTraceReceiveOperation now use kqueue-backed DispatchSourceRead for ICMP socket readiness, replacing the legacy poll(2) busy loop
  • DispatchSourceTimer replaces manual deadline arithmetic for both the overall timeout and the streaming retry timer
  • Eliminates thread-blocking: the cooperative thread pool is never stalled waiting for socket data
  • Completes the I/O modernization started in v0.11.2 (TCP/UDP probes) and v0.8.0 (ping), bringing all socket-based operations to event-driven I/O

Concurrency Bug Fixes

Data race elimination in trace operations

  • TraceReceiveOperation.cancel() now sets the finished flag under lock and dispatches source cleanup to the serial queue, preventing races between cancellation (any thread) and handleRead()/setupSources() (serial queue)
  • Same fix applied to StreamingTraceReceiveOperation.cancel()
  • finish() in both operations simplified to only run on the serial queue — hops, reachedTTL, and receivedTTLs no longer need lock-protected copies since they're only mutated on that same queue
  • setupSources() now guards against setup after cancel() has already completed, preventing leaked DispatchSources that would hold strong references to the operation

HTTPProbe delegate thread safety

  • NoRedirectDelegate and MetricsDelegate now protect taskMetrics with NSLock, eliminating a theoretical data race between URLSession's internal queue and the caller's extractTimingMetrics() read

Config Validation

  • SwiftFTRConfig.init(): precondition that maxHops is 1...255, maxWaitMs is positive, payloadSize is non-negative
  • StreamingTraceConfig.init(): precondition that maxHops is 1...255, probeTimeout is positive
  • Prevents runtime crashes from 1...0 range construction when maxHops == 0

Compatibility

  • No breaking changes to public APIs
  • All 157 tests passing
  • Requires macOS 13+, Swift 6.1+

What's Changed

  • Housekeeping + traceroute I/O modernization (v0.12.0) by @dweekly in #13

Full Changelog: v0.11.5...v0.12.0

Contributors

dweekly
Assets 6
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