fix(bridge): defer dylib init off the constructor (macOS 26 dyld init-order)

CHANGELOG.md

@@ -9,6 +9,9 @@
 ### Local Lookups
 - feat: add `--local` modes for `account`, `whois`, and `nickname` so common introspection can read local history or Contacts without launching the IMCore bridge (#132, thanks @ranaroussi).
 
+### Advanced IMCore
+- fix: defer injected bridge bootstrap until after Messages startup so macOS 26 dyld constructor ordering cannot touch ObjC/Foundation/IMCore before the process is ready (#138, thanks @omarshahine).
+
 ## 0.10.0 - 2026-05-28
 
 ### Watch

Sources/IMsgHelper/IMsgInjected.m

@@ -4371,45 +4371,77 @@ static void startV2InboxWatcher(void) {
 
 #pragma mark - Dylib Entry Point
 
-__attribute__((constructor))
-static void injectedInit(void) {
-    NSLog(@"[imsg-bridge] Dylib injected into %@", [[NSProcessInfo processInfo] processName]);
-
-    // Connect to IMDaemon for full IMCore access
-    Class daemonClass = NSClassFromString(@"IMDaemonController");
-    if (daemonClass) {
-        id daemon = [daemonClass performSelector:@selector(sharedInstance)];
-        if (daemon && [daemon respondsToSelector:@selector(connectToDaemon)]) {
-            [daemon performSelector:@selector(connectToDaemon)];
-            NSLog(@"[imsg-bridge] Connected to IMDaemon");
-        } else {
-            NSLog(@"[imsg-bridge] IMDaemonController available but couldn't connect");
-        }
-    } else {
-        NSLog(@"[imsg-bridge] IMDaemonController class not found");
-    }
-
-    // Delay initialization to let Messages.app fully start
-    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, 2 * NSEC_PER_SEC), dispatch_get_main_queue(), ^{
-        NSLog(@"[imsg-bridge] Initializing after delay...");
+// Bridge bootstrap. Intentionally NOT run from the dylib constructor: macOS 26
+// tightened dyld initializer ordering for platform/system apps, so touching
+// ObjC/Foundation/IMCore at constructor time can execute before libSystem has
+// finished bootstrapping ("dyld initialized but libSystem has not") and abort
+// Messages.app on launch. injectedInit() only schedules this delayed bootstrap;
+// the lock file is written after the watchers are installed below.
+static void bridgeBootstrap(void) {
+    static dispatch_once_t once;
+    dispatch_once(&once, ^{
+        @autoreleasepool {
+            initFilePaths();
+            NSLog(@"[imsg-bridge] Dylib injected into %@",
+                  [[NSProcessInfo processInfo] processName]);
+            debugLog(@"bootstrap starting in process=%@ pid=%d",
+                     [[NSProcessInfo processInfo] processName], getpid());
+
+            // Connect to IMDaemon for full IMCore access
+            Class daemonClass = NSClassFromString(@"IMDaemonController");
+            if (daemonClass) {
+                id daemon = [daemonClass performSelector:@selector(sharedInstance)];
+                if (daemon && [daemon respondsToSelector:@selector(connectToDaemon)]) {
+                    [daemon performSelector:@selector(connectToDaemon)];
+                    NSLog(@"[imsg-bridge] Connected to IMDaemon");
+                    debugLog(@"connected to IMDaemon");
+                } else {
+                    NSLog(@"[imsg-bridge] IMDaemonController available but couldn't connect");
+                    debugLog(@"IMDaemonController available but couldn't connect");
+                }
+            } else {
+                NSLog(@"[imsg-bridge] IMDaemonController class not found");
+                debugLog(@"IMDaemonController class not found");
+            }
 
-        // Log IMCore status
-        Class registryClass = NSClassFromString(@"IMChatRegistry");
-        if (registryClass) {
-            id registry = [registryClass performSelector:@selector(sharedInstance)];
-            if ([registry respondsToSelector:@selector(allExistingChats)]) {
-                NSArray *chats = [registry performSelector:@selector(allExistingChats)];
-                NSLog(@"[imsg-bridge] IMChatRegistry available with %lu chats",
-                      (unsigned long)chats.count);
+            NSLog(@"[imsg-bridge] Initializing after delay...");
+
+            // Log IMCore status
+            Class registryClass = NSClassFromString(@"IMChatRegistry");
+            if (registryClass) {
+                id registry = [registryClass performSelector:@selector(sharedInstance)];
+                if ([registry respondsToSelector:@selector(allExistingChats)]) {
+                    NSArray *chats = [registry performSelector:@selector(allExistingChats)];
+                    NSLog(@"[imsg-bridge] IMChatRegistry available with %lu chats",
+                          (unsigned long)chats.count);
+                    debugLog(@"IMChatRegistry available chats=%lu",
+                             (unsigned long)chats.count);
+                }
+            } else {
+                NSLog(@"[imsg-bridge] IMChatRegistry NOT available");
+                debugLog(@"IMChatRegistry not available");
             }
-        } else {
-            NSLog(@"[imsg-bridge] IMChatRegistry NOT available");
+
+            probeSelectors();
+            startFileWatcher();
+            startV2InboxWatcher();
+            registerEventObservers();
+            debugLog(@"bootstrap complete");
         }
+    });
+}
 
-        probeSelectors();
-        startFileWatcher();
-        startV2InboxWatcher();
-        registerEventObservers();
+__attribute__((constructor))
+static void injectedInit(void) {
+    // Keep the constructor tiny: only enqueue onto the main queue with
+    // libdispatch. Start the startup delay from that first main-queue turn so
+    // bridgeBootstrap cannot become ready to run before Messages services the
+    // queue for the first time.
+    dispatch_async(dispatch_get_main_queue(), ^{
+        dispatch_after(dispatch_time(DISPATCH_TIME_NOW, 2 * NSEC_PER_SEC),
+                       dispatch_get_main_queue(), ^{
+            bridgeBootstrap();
+        });
     });
 }
 

Tests/imsgTests/BridgeCommandRegistrationTests.swift

@@ -148,6 +148,37 @@ func injectedHelperWiresNativePollSend() throws {
     ))
 }
 
+@Test
+func injectedHelperConstructorOnlySchedulesDelayedBootstrap() throws {
+  let testFile = URL(fileURLWithPath: #filePath)
+  let repoRoot =
+    testFile
+    .deletingLastPathComponent()
+    .deletingLastPathComponent()
+    .deletingLastPathComponent()
+  let helper = repoRoot.appendingPathComponent("Sources/IMsgHelper/IMsgInjected.m")
+  let source = stripObjectiveCComments(try String(contentsOf: helper, encoding: .utf8))
+  let constructorBody = try #require(functionBody(named: "injectedInit", in: source))
+  let bootstrapBody = try #require(functionBody(named: "bridgeBootstrap", in: source))
+
+  #expect(constructorBody.contains("dispatch_after"))
+  #expect(constructorBody.contains("dispatch_async"))
+  #expect(constructorBody.contains("bridgeBootstrap();"))
+  #expect(!constructorBody.contains("NSLog"))
+  #expect(!constructorBody.contains("NSProcessInfo"))
+  #expect(!constructorBody.contains("NSClassFromString"))
+  #expect(!constructorBody.contains("IMDaemonController"))
+  #expect(!constructorBody.contains("startFileWatcher"))
+  #expect(!constructorBody.contains("startV2InboxWatcher"))
+
+  #expect(bootstrapBody.contains("dispatch_once"))
+  #expect(bootstrapBody.contains("@autoreleasepool"))
+  #expect(bootstrapBody.contains("connectToDaemon"))
+  #expect(bootstrapBody.contains("startFileWatcher()"))
+  #expect(bootstrapBody.contains("startV2InboxWatcher()"))
+  #expect(bootstrapBody.contains("registerEventObservers()"))
+}
+
 private func stripObjectiveCComments(_ source: String) -> String {
   source
     .replacingOccurrences(of: #"/\*[\s\S]*?\*/"#, with: "", options: .regularExpression)