fix: Crash in SentryFramesTracker.removeListener

CHANGELOG.md

@@ -15,6 +15,7 @@
 - Fix `raw_description` in `runtime` context on Mac Catalyst (#7082)
 - Deprecates `configureDarkTheme` for user feedback (#7114)
 - Fix incorrect variable assignment for 'sampled' key (#7120)
+- Resolve crash in caused by calling `SentryFramesTracker.removeListener(_:)` (#7155)
 
 ## 9.1.0
 

Sources/Swift/Core/Integrations/FramesTracking/SentryFramesTracker.swift

@@ -18,12 +18,11 @@ public protocol SentryFramesTrackerListener: NSObjectProtocol {
 
 @_spi(Private) @objc
 public class SentryFramesTracker: NSObject {
-
-    var isStarted: Bool = false
+    
+    private var isStarted: Bool = false
     @objc public private(set) var isRunning: Bool = false
 
     // MARK: Private properties
-    private var lock = NSLock()
     private var previousFrameTimestamp: CFTimeInterval = SentryFramesTracker.previousFrameInitialValue
     private var previousFrameSystemTimestamp: UInt64 = 0
     private var currentFrameRate: UInt64 = 60
@@ -68,11 +67,22 @@ public class SentryFramesTracker: NSObject {
         resetFrames()
         SentrySDKLog.debug("Initialized frame tracker")
     }
+
+    deinit {
+        // Need to invalidate so DisplayLink is releasing this object. Calling this is thread-safe.
+        displayLinkWrapper.invalidate()
+    }
 
     // MARK: - Public Methods
 
     @objc
     public func start() {
+        dispatchQueueWrapper.dispatchAsyncOnMainQueueIfNotMainThread {
+            self.startInternal()
+        }
+    }
+
+    private func startInternal() {
         guard !isStarted else { return }
 
         isStarted = true
@@ -96,6 +106,12 @@ public class SentryFramesTracker: NSObject {
 
     @objc
     public func stop() {
+        dispatchQueueWrapper.dispatchAsyncOnMainQueueIfNotMainThread {
+            self.stopInternal()
+        }
+    }
+
+    private func stopInternal() {
         guard isStarted else { return }
 
         isStarted = false
@@ -114,9 +130,7 @@ public class SentryFramesTracker: NSObject {
             object: nil
         )
 
-        lock.synchronized {
-            listeners.removeAllObjects()
-        }
+        listeners.removeAllObjects()
     }
 
     @objc
@@ -170,10 +184,6 @@ public class SentryFramesTracker: NSObject {
             self.listeners.remove(listener)
         }
     }
-
-    deinit {
-        stop()
-    }
 
 #if os(iOS)
     @objc public func resetProfilingTimestamps() {
@@ -222,7 +232,7 @@ public class SentryFramesTracker: NSObject {
     private func willResignActive() {
         pause()
     }
-
+    
     private func unpause() {
         guard !isRunning else { return }
 

Tests/SentryTests/Integrations/Performance/FramesTracking/SentryFramesTrackerTests.swift

@@ -7,7 +7,7 @@ import XCTest
 // This test class also includes tests for delayed frames calculation which is quite complex.
 
 #if os(iOS) || os(tvOS) || targetEnvironment(macCatalyst)
-class SentryFramesTrackerTests: XCTestCase {
+final class SentryFramesTrackerTests: XCTestCase {
 
     private class Fixture {
 
@@ -775,6 +775,21 @@ class SentryFramesTrackerTests: XCTestCase {
         XCTAssertEqual(dispatchQueueWrapper.blockOnMainInvocations.count, 1)
     }
 
+    func testListenersAreRemovedInMainThread() {
+        let dispatchQueueWrapper = TestSentryDispatchQueueWrapper()
+        let sut = SentryFramesTracker(displayLinkWrapper: fixture.displayLinkWrapper, dateProvider: fixture.dateProvider, dispatchQueueWrapper: dispatchQueueWrapper, notificationCenter: fixture.notificationCenter, delayedFramesTracker: TestDelayedWrapper(keepDelayedFramesDuration: fixture.keepDelayedFramesDuration, dateProvider: fixture.dateProvider))
+        let listener = FrameTrackerListener()
+
+        sut.addListener(listener)
+        sut.start()
+
+        XCTAssertEqual(dispatchQueueWrapper.blockOnMainInvocations.count, 2)
+
+        sut.stop()
+
+        XCTAssertEqual(dispatchQueueWrapper.blockOnMainInvocations.count, 3)
+    }
+
     func testRemoveListener() {
         let sut = fixture.sut
         let listener = FrameTrackerListener()