From f38bc3b7757726f9f7fe86b36675cd13799f3452 Mon Sep 17 00:00:00 2001
From: Lawrence Chen <54008264+lawrencecchen@users.noreply.github.com>
Date: Wed, 25 Feb 2026 18:02:00 -0800
Subject: [PATCH] Move LaunchServices bundle registration off main thread
 (#513)

Fixes CMUXTERM-MACOS-DS
---
 Sources/AppDelegate.swift                     | 59 +++++++++++++++++--
 cmuxTests/CmuxWebViewKeyEquivalentTests.swift | 29 +++++++++
 2 files changed, 82 insertions(+), 6 deletions(-)

diff --git a/Sources/AppDelegate.swift b/Sources/AppDelegate.swift
index 73871cad..5f4bc8d2 100644
--- a/Sources/AppDelegate.swift
+++ b/Sources/AppDelegate.swift
@@ -734,6 +734,13 @@ final class AppDelegate: NSObject, NSApplicationDelegate, UNUserNotificationCent
         label: "com.cmuxterm.app.sessionPersistence",
         qos: .utility
     )
+    private static let launchServicesRegistrationQueue = DispatchQueue(
+        label: "com.cmuxterm.app.launchServicesRegistration",
+        qos: .utility
+    )
+    private static func enqueueLaunchServicesRegistrationWork(_ work: @escaping @Sendable () -> Void) {
+        launchServicesRegistrationQueue.async(execute: work)
+    }
     private var lastSessionAutosaveFingerprint: Int?
     private var lastSessionAutosavePersistedAt: Date = .distantPast
     private var didHandleExplicitOpenIntentAtStartup = false
@@ -851,7 +858,7 @@ final class AppDelegate: NSObject, NSApplicationDelegate, UNUserNotificationCent
         if !isRunningUnderXCTest {
             DispatchQueue.main.async { [weak self] in
                 guard let self else { return }
-                self.registerLaunchServicesBundle()
+                self.scheduleLaunchServicesBundleRegistration()
                 self.enforceSingleInstance()
                 self.observeDuplicateLaunches()
             }
@@ -5678,14 +5685,54 @@ final class AppDelegate: NSObject, NSApplicationDelegate, UNUserNotificationCent
         }
     }
 
-    private func registerLaunchServicesBundle() {
-        let bundleURL = Bundle.main.bundleURL.standardizedFileURL
-        let registerStatus = LSRegisterURL(bundleURL as CFURL, true)
-        if registerStatus != noErr {
-            NSLog("LaunchServices registration failed (status: \(registerStatus)) for \(bundleURL.path)")
+    private func scheduleLaunchServicesBundleRegistration(
+        bundleURL: URL = Bundle.main.bundleURL.standardizedFileURL,
+        scheduler: @escaping (@escaping @Sendable () -> Void) -> Void = AppDelegate.enqueueLaunchServicesRegistrationWork,
+        register: @escaping (CFURL) -> OSStatus = { url in
+            LSRegisterURL(url, true)
+        },
+        breadcrumb: @escaping (_ message: String, _ data: [String: Any]) -> Void = { message, data in
+            sentryBreadcrumb(message, category: "startup", data: data)
+        }
+    ) {
+        let normalizedURL = bundleURL.standardizedFileURL
+        breadcrumb("launchservices.register.schedule", [
+            "bundlePath": normalizedURL.path
+        ])
+
+        scheduler {
+            let startedAt = CFAbsoluteTimeGetCurrent()
+            let registerStatus = register(normalizedURL as CFURL)
+            let durationMs = Int(((CFAbsoluteTimeGetCurrent() - startedAt) * 1000).rounded())
+
+            breadcrumb("launchservices.register.complete", [
+                "bundlePath": normalizedURL.path,
+                "status": Int(registerStatus),
+                "durationMs": durationMs
+            ])
+
+            if registerStatus != noErr {
+                NSLog("LaunchServices registration failed (status: \(registerStatus)) for \(normalizedURL.path)")
+            }
         }
     }
 
+#if DEBUG
+    func scheduleLaunchServicesBundleRegistrationForTesting(
+        bundleURL: URL,
+        scheduler: @escaping (@escaping @Sendable () -> Void) -> Void,
+        register: @escaping (CFURL) -> OSStatus,
+        breadcrumb: @escaping (_ message: String, _ data: [String: Any]) -> Void = { _, _ in }
+    ) {
+        scheduleLaunchServicesBundleRegistration(
+            bundleURL: bundleURL,
+            scheduler: scheduler,
+            register: register,
+            breadcrumb: breadcrumb
+        )
+    }
+#endif
+
     private func enforceSingleInstance() {
         guard let bundleId = Bundle.main.bundleIdentifier else { return }
         let currentPid = ProcessInfo.processInfo.processIdentifier
diff --git a/cmuxTests/CmuxWebViewKeyEquivalentTests.swift b/cmuxTests/CmuxWebViewKeyEquivalentTests.swift
index cc30b12f..806338a9 100644
--- a/cmuxTests/CmuxWebViewKeyEquivalentTests.swift
+++ b/cmuxTests/CmuxWebViewKeyEquivalentTests.swift
@@ -684,6 +684,35 @@ final class AppDelegateWindowContextRoutingTests: XCTestCase {
     }
 }
 
+@MainActor
+final class AppDelegateLaunchServicesRegistrationTests: XCTestCase {
+    func testScheduleLaunchServicesRegistrationDefersRegisterWork() {
+        _ = NSApplication.shared
+        let app = AppDelegate()
+
+        var scheduledWork: (@Sendable () -> Void)?
+        var registerCallCount = 0
+
+        app.scheduleLaunchServicesBundleRegistrationForTesting(
+            bundleURL: URL(fileURLWithPath: "/tmp/../tmp/cmux-launch-services-test.app"),
+            scheduler: { work in
+                scheduledWork = work
+            },
+            register: { _ in
+                registerCallCount += 1
+                return noErr
+            }
+        )
+
+        XCTAssertEqual(registerCallCount, 0, "Registration should not run inline on the startup call path")
+        XCTAssertNotNil(scheduledWork, "Registration work should be handed to the scheduler")
+
+        scheduledWork?()
+
+        XCTAssertEqual(registerCallCount, 1)
+    }
+}
+
 final class FocusFlashPatternTests: XCTestCase {
     func testFocusFlashPatternMatchesTerminalDoublePulseShape() {
         XCTAssertEqual(FocusFlashPattern.values, [0, 1, 0, 1, 0])