fix: Missing UIViewController traces with Xcode 16 (#4523)

Xcode 16 introduces a new flag ENABLE_DEBUG_DYLIB. If this flag is
enabled, debug builds of app and app extension targets on supported
platforms and SDKs will be built with the main binary code in a separate
“NAME.debug.dylib”. Our swizzling logic for UIViewControllers sometimes
skipped swizzling the UIViewControllers in that debug.dylib binary. This
is fixed now, by swizzling all matching inAppInclude binary images that
the binary image cache returns and not only the first one.

CHANGELOG.md

@@ -9,6 +9,7 @@
 ### Fixes
 
 - Keep PropagationContext when cloning scope (#4518)
+- UIViewController with Xcode 16 in debug (#4523). The Xcode 16 build setting [ENABLE_DEBUG_DYLIB](https://developer.apple.com/documentation/xcode/build-settings-reference#Enable-Debug-Dylib-Support), which is turned on by default only in debug, could lead to missing UIViewController traces.
 - Concurrency crash with Swift 6 (#4512)
 
 ## 8.40.1

Sources/Sentry/SentryBinaryImageCache.m

@@ -141,16 +141,18 @@ - (NSInteger)indexOfImage:(uint64_t)address
     return -1; // Address not found
 }
 
-- (nullable NSString *)pathForInAppInclude:(NSString *)inAppInclude
+- (NSSet<NSString *> *)imagePathsForInAppInclude:(NSString *)inAppInclude
 {
+    NSMutableSet<NSString *> *imagePaths = [NSMutableSet new];
+
     @synchronized(self) {
         for (SentryBinaryImageInfo *info in _cache) {
             if ([SentryInAppLogic isImageNameInApp:info.name inAppInclude:inAppInclude]) {
-                return info.name;
+                [imagePaths addObject:info.name];
             }
         }
     }
-    return nil;
+    return imagePaths;
 }
 
 @end

Sources/Sentry/SentrySubClassFinder.m

@@ -49,6 +49,8 @@ - (void)actOnSubclassesOfViewControllerInImage:(NSString *)imageName block:(void
             copyClassNamesForImage:[imageName cStringUsingEncoding:NSUTF8StringEncoding]
                             amount:&count];
 
+        SENTRY_LOG_DEBUG(@"Found %u number of classes in image: %@.", count, imageName);
+
         // Storing the actual classes in an NSArray would call initializer of the class, which we
         // must avoid as we are on a background thread here and dealing with UIViewControllers,
         // which assume they are running on the main thread. Therefore, we store the class name
@@ -87,9 +89,9 @@ - (void)actOnSubclassesOfViewControllerInImage:(NSString *)imageName block:(void
                 block(NSClassFromString(className));
             }
 
-            SENTRY_LOG_DEBUG(
-                @"The following UIViewControllers will generate automatic transactions: %@",
-                [classesToSwizzle componentsJoinedByString:@", "]);
+            SENTRY_LOG_DEBUG(@"The following UIViewControllers for image: %@ will generate "
+                             @"automatic transactions: %@",
+                imageName, [classesToSwizzle componentsJoinedByString:@", "]);
         }];
     }];
 }

Sources/Sentry/SentryUIViewControllerSwizzling.m

@@ -79,12 +79,17 @@ - (instancetype)initWithOptions:(SentryOptions *)options
 - (void)start
 {
     for (NSString *inAppInclude in self.inAppLogic.inAppIncludes) {
-        NSString *pathToImage = [self.binaryImageCache pathForInAppInclude:inAppInclude];
-        if (pathToImage != nil) {
-            [self swizzleUIViewControllersOfImage:pathToImage];
+        NSSet<NSString *> *imagePathsToInAppInclude =
+            [self.binaryImageCache imagePathsForInAppInclude:inAppInclude];
+
+        if (imagePathsToInAppInclude.count > 0) {
+            for (NSString *imagePath in imagePathsToInAppInclude) {
+                [self swizzleUIViewControllersOfImage:imagePath];
+            }
         } else {
-            SENTRY_LOG_WARN(@"Failed to find the binary image for inAppInclude <%@> and, therefore "
-                            @"can't instrument UIViewControllers in that binary",
+            SENTRY_LOG_WARN(
+                @"Failed to find the binary image(s) for inAppInclude <%@> and, therefore "
+                @"can't instrument UIViewControllers in these binaries.",
                 inAppInclude);
         }
     }

Sources/Sentry/include/HybridPublic/SentryBinaryImageCache.h

@@ -24,7 +24,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (nullable SentryBinaryImageInfo *)imageByAddress:(const uint64_t)address;
 
-- (nullable NSString *)pathForInAppInclude:(NSString *)inAppInclude;
+- (NSSet<NSString *> *)imagePathsForInAppInclude:(NSString *)inAppInclude;
 
 + (NSString *_Nullable)convertUUID:(const unsigned char *const)value;
 

Tests/SentryTests/Integrations/Performance/UIViewController/SentryUIViewControllerSwizzlingTests.swift

@@ -25,11 +25,6 @@ class SentryUIViewControllerSwizzlingTests: XCTestCase {
                 cString: class_getImageName(SentryUIViewControllerSwizzlingTests.self)!,
                 encoding: .utf8)! as NSString
             options.add(inAppInclude: imageName.lastPathComponent)
-
-            let externalImageName = String(
-                cString: class_getImageName(ExternalUIViewController.self)!,
-                encoding: .utf8)! as NSString
-            options.add(inAppInclude: externalImageName.lastPathComponent)
         }
 
         var sut: SentryUIViewControllerSwizzling {
@@ -167,13 +162,59 @@ class SentryUIViewControllerSwizzlingTests: XCTestCase {
     }
 
     func testSwizzlingOfExternalLibs() {
+        let externalImageName = String(
+            cString: class_getImageName(ExternalUIViewController.self)!,
+            encoding: .utf8)! as NSString
+        fixture.options.add(inAppInclude: externalImageName.lastPathComponent)
+
         let sut = fixture.sut
         sut.start()
         let controller = ExternalUIViewController()
         controller.loadView()
         XCTAssertNotNil(SentrySDK.span)
     }
 
+    func testSwizzleInAppIncludes_WithShortenedInAppInclude() throws {
+        let imageName = try XCTUnwrap(String(
+            cString: class_getImageName(ExternalUIViewController.self)!,
+            encoding: .utf8) as? NSString)
+
+        let lastPathComponent = String(imageName.lastPathComponent)
+        let shortenedLastPathComponent = String(lastPathComponent.prefix(5))
+
+        fixture.options.add(inAppInclude: shortenedLastPathComponent)
+
+        let sut = fixture.sut
+        sut.start()
+        let controller = ExternalUIViewController()
+        controller.loadView()
+        XCTAssertNotNil(SentrySDK.span)
+    }
+
+    /// Xcode 16 introduces a new flag ENABLE_DEBUG_DYLIB (https://developer.apple.com/documentation/xcode/build-settings-reference#Enable-Debug-Dylib-Support)
+    /// If this flag is enabled, debug builds of app and app extension targets on supported platforms and SDKs
+    /// will be built with the main binary code in a separate “NAME.debug.dylib”.
+    /// This test adds this debug.dylib and checks if it gets swizzled.
+    func testSwizzle_DebugDylib_GetsSwizzled() {
+        let imageName = String(
+            cString: class_getImageName(SentryUIViewControllerSwizzlingTests.self)!,
+            encoding: .utf8)! as NSString
+
+        let debugDylib = "\(imageName).debug.dylib"
+
+        var image = createCrashBinaryImage(0, name: debugDylib)
+        SentryDependencyContainer.sharedInstance().binaryImageCache.start()
+        SentryDependencyContainer.sharedInstance().binaryImageCache.binaryImageAdded(&image)
+
+        let sut = fixture.sut
+        sut.start()
+
+        let subClassFinderInvocations = fixture.subClassFinder.invocations
+        let result = subClassFinderInvocations.invocations.filter { $0.imageName == debugDylib }
+
+        XCTAssertEqual(1, result.count)
+    }
+
     func testSwizzle_fromScene_invalidNotification_NoObject() {
         let swizzler = fixture.testableSut
 

Tests/SentryTests/SentryBinaryImageCacheTests.swift

@@ -122,17 +122,17 @@ class SentryBinaryImageCacheTests: XCTestCase {
         sut.binaryImageAdded(&binaryImage)
         sut.binaryImageAdded(&binaryImage2)
 
-        let path = sut.pathFor(inAppInclude: "Expected Name at 0")
-        XCTAssertEqual(path, "Expected Name at 0")
+        let paths = sut.imagePathsFor(inAppInclude: "Expected Name at 0")
+        XCTAssertEqual(paths.first, "Expected Name at 0")
 
-        let path2 = sut.pathFor(inAppInclude: "Expected Name at 1")
-        XCTAssertEqual(path2, "Expected Name at 1")
+        let paths2 = sut.imagePathsFor(inAppInclude: "Expected Name at 1")
+        XCTAssertEqual(paths2.first, "Expected Name at 1")
 
-        let path3 = sut.pathFor(inAppInclude: "Expected")
-        XCTAssertEqual(path3, "Expected Name at 0")
+        let bothPaths = sut.imagePathsFor(inAppInclude: "Expected")
+        XCTAssertEqual(bothPaths, ["Expected Name at 0", "Expected Name at 1"])
 
-        let didNotFind = sut.pathFor(inAppInclude: "Name at 0")
-        XCTAssertNil(didNotFind)
+        let didNotFind = sut.imagePathsFor(inAppInclude: "Name at 0")
+        XCTAssertTrue(didNotFind.isEmpty)
     }
 
     func testBinaryImageWithNULLName_DoesNotAddImage() {
@@ -193,7 +193,7 @@ class SentryBinaryImageCacheTests: XCTestCase {
 
         for i in 0..<count {
             DispatchQueue.global().async {
-                var binaryImage0 = self.createCrashBinaryImage(UInt(i * 10))
+                var binaryImage0 = createCrashBinaryImage(UInt(i * 10))
                 self.sut.binaryImageAdded(&binaryImage0)
 
                 self.sut.stop()
@@ -204,32 +204,31 @@ class SentryBinaryImageCacheTests: XCTestCase {
 
         waitForExpectations(timeout: 1)
     }
+}
 
-    func createCrashBinaryImage(_ address: UInt, vmAddress: UInt64 = 0) -> SentryCrashBinaryImage {
-        let name = "Expected Name at \(address)"
-        let nameCString = name.withCString { strdup($0) }
-
-        var uuidPointer = UnsafeMutablePointer<UInt8>(nil)
-        let uuidAsCharArray: [UInt8] = [132, 186, 235, 218, 173, 26, 51, 244, 179, 93, 138, 69, 245, 218, 243, 34]
-        uuidPointer = UnsafeMutablePointer<UInt8>.allocate(capacity: uuidAsCharArray.count)
-        uuidPointer?.initialize(from: uuidAsCharArray, count: uuidAsCharArray.count)
-
-        let binaryImage = SentryCrashBinaryImage(
-            address: UInt64(address),
-            vmAddress: vmAddress,
-            size: 100,
-            name: nameCString,
-            uuid: uuidPointer,
-            cpuType: 1,
-            cpuSubType: 1,
-            majorVersion: 1,
-            minorVersion: 0,
-            revisionVersion: 0,
-            crashInfoMessage: nil,
-            crashInfoMessage2: nil
-        )
-
-        return binaryImage
-    }
-
+func createCrashBinaryImage(_ address: UInt, vmAddress: UInt64 = 0, name: String? = nil) -> SentryCrashBinaryImage {
+    let imageName = name ?? "Expected Name at \(address)"
+    let nameCString = imageName.withCString { strdup($0) }
+
+    var uuidPointer = UnsafeMutablePointer<UInt8>(nil)
+    let uuidAsCharArray: [UInt8] = [132, 186, 235, 218, 173, 26, 51, 244, 179, 93, 138, 69, 245, 218, 243, 34]
+    uuidPointer = UnsafeMutablePointer<UInt8>.allocate(capacity: uuidAsCharArray.count)
+    uuidPointer?.initialize(from: uuidAsCharArray, count: uuidAsCharArray.count)
+
+    let binaryImage = SentryCrashBinaryImage(
+        address: UInt64(address),
+        vmAddress: vmAddress,
+        size: 100,
+        name: nameCString,
+        uuid: uuidPointer,
+        cpuType: 1,
+        cpuSubType: 1,
+        majorVersion: 1,
+        minorVersion: 0,
+        revisionVersion: 0,
+        crashInfoMessage: nil,
+        crashInfoMessage2: nil
+    )
+
+    return binaryImage
 }