Thread sanitizer reports a warning in SessionManager

[kkostov]

Hi @Jeehut,

After upgrading to 2.9.1 in the FlutterSDK, I noticed that when thread sanitizer is active for the current target on macOS, a violation is reported in SessionManager at self.recentSessions[existingSessionIndex].durationInSeconds = Int(self.currentSessionDuration):

The error

[siracusa]

I'm getting the same warning using 2.9.2.

[Jeehut]

@siracusa Can you please give additional context on what platform your app was running on? Was it also macOS?

[siracusa]

Yes, I'm building my app on macOS 15.4 (24E248) using Xcode 16.2 (16C5032a)

[siracusa]

ThreadSanitizer is still showing an error when using version 2.9.4 of the SDK. Here's an example:

WARNING: ThreadSanitizer: Swift access race (pid=1727)
  Modifying access of Swift variable at 0x7214000605f0 by main thread:
    #0 TelemetryDeck.SessionManager.(persistCurrentSessionIfNeeded in _3BDC4F4FAC8149DDD59554E41258192D)() -> () <null> (Hyperspace.debug.dylib:x86_64+0x9bf6c2)
    #1 TelemetryDeck.SessionManager.(updateSessionDuration in _3BDC4F4FAC8149DDD59554E41258192D)() -> () <null> (Hyperspace.debug.dylib:x86_64+0x9bf004)
    #2 @objc TelemetryDeck.SessionManager.(updateSessionDuration in _3BDC4F4FAC8149DDD59554E41258192D)() -> () <null> (Hyperspace.debug.dylib:x86_64+0x9bfd8e)
    #3 __NSFireTimer <null> (Foundation:x86_64+0x441fd)
    #4 __debug_main_executable_dylib_entry_point <null> (Hyperspace.debug.dylib:x86_64+0x2868b5)
    #5 start <null> (dyld:x86_64+0xfffffffffffd9780)

  Previous read of size 8 at 0x7214000605f0 by thread T20:
    #0 closure #2 @Sendable () -> () in TelemetryDeck.SessionManager.(persistCurrentSessionIfNeeded in _3BDC4F4FAC8149DDD59554E41258192D)() -> () <null> (Hyperspace.debug.dylib:x86_64+0x9c0078)
    #1 partial apply forwarder for closure #2 @Sendable () -> () in TelemetryDeck.SessionManager.(persistCurrentSessionIfNeeded in _3BDC4F4FAC8149DDD59554E41258192D)() -> () <null> (Hyperspace.debug.dylib:x86_64+0x9c10dd)
    #2 reabstraction thunk helper from @escaping @callee_guaranteed @Sendable () -> () to @escaping @callee_unowned @convention(block) @Sendable () -> () <null> (Hyperspace.debug.dylib:x86_64+0x9b7f72)
    #3 __tsan::invoke_and_release_block(void*) <null> (libclang_rt.tsan_osx_dynamic.dylib:x86_64h+0x7e2bb)
    #4 _dispatch_client_callout <null> (libdispatch.dylib:x86_64+0x1b369)

  Location is heap block of size 72 at 0x7214000605e0 allocated by main thread:
    #0 malloc <null> (libclang_rt.tsan_osx_dynamic.dylib:x86_64h+0x5bd1e)
    #1 _malloc_type_malloc_outlined <null> (libsystem_malloc.dylib:x86_64+0x1ce78)
    #2 one-time initialization function for shared <null> (Hyperspace.debug.dylib:x86_64+0x9b6903)
    #3 dispatch_once <null> (libclang_rt.tsan_osx_dynamic.dylib:x86_64h+0x7f110)
    #4 dispatch_once_f <null> (libclang_rt.tsan_osx_dynamic.dylib:x86_64h+0x7f1b6)
    #5 TelemetryDeck.SessionManager.shared.unsafeMutableAddressor : TelemetryDeck.SessionManager <null> (Hyperspace.debug.dylib:x86_64+0x9b6a96)
    #6 static TelemetryDeck.DefaultSignalPayload.parameters.getter : Swift.Dictionary<Swift.String, Swift.String> <null> (Hyperspace.debug.dylib:x86_64+0x9f5409)
    #7 closure #1 @Swift.MainActor @Sendable () -> () in TelemetryDeck.SignalManager.processSignal(_: Swift.String, parameters: Swift.Dictionary<Swift.String, Swift.String>, floatValue: Swift.Optional<Swift.Double>, customUserID: Swift.Optional<Swift.String>, configuration: TelemetryDeck.TelemetryManagerConfiguration) -> () <null> (Hyperspace.debug.dylib:x86_64+0xa0004b)
    #8 partial apply forwarder for closure #1 @Swift.MainActor @Sendable () -> () in TelemetryDeck.SignalManager.processSignal(_: Swift.String, parameters: Swift.Dictionary<Swift.String, Swift.String>, floatValue: Swift.Optional<Swift.Double>, customUserID: Swift.Optional<Swift.String>, configuration: TelemetryDeck.TelemetryManagerConfiguration) -> () <null> (Hyperspace.debug.dylib:x86_64+0xa03b2d)
    #9 reabstraction thunk helper from @escaping @callee_guaranteed @Sendable () -> () to @escaping @callee_unowned @convention(block) @Sendable () -> () <null> (Hyperspace.debug.dylib:x86_64+0x9b7f72)
    #10 __tsan::invoke_and_release_block(void*) <null> (libclang_rt.tsan_osx_dynamic.dylib:x86_64h+0x7e2bb)
    #11 _dispatch_client_callout <null> (libdispatch.dylib:x86_64+0x1b369)
    #12 __debug_main_executable_dylib_entry_point <null> (Hyperspace.debug.dylib:x86_64+0x2868b5)
    #13 start <null> (dyld:x86_64+0xfffffffffffd9780)

  Thread T20 (tid=35277, running) is a GCD worker thread

SUMMARY: ThreadSanitizer: Swift access race (/Users/testdev/Library/Developer/Xcode/DerivedData/Hyperspace-faiozwxjhmrzxccuvszimfgpdpre/Build/Products/Debug/Hyperspace.app/Contents/MacOS/Hyperspace.debug.dylib:x86_64+0x9bf6c2) in TelemetryDeck.SessionManager.(persistCurrentSessionIfNeeded in _3BDC4F4FAC8149DDD59554E41258192D)() -> ()+0x692