fix: show sidebar update banner from background checks (#1543)

Sources/Update/UpdateController.swift

@@ -27,10 +27,10 @@ class UpdateController {
     }
 
     init() {
-        // Default to manual update checks. This also prevents Sparkle from prompting at startup.
+        // cmux checks for updates in the background, but keeps automatic download and
+        // profile submission disabled so all install intent stays user-driven.
         let defaults = UserDefaults.standard
         defaults.register(defaults: [
-            "SUEnableAutomaticChecks": false,
             "SUSendProfileInfo": false,
             "SUAutomaticallyUpdate": false,
         ])
@@ -59,8 +59,8 @@ class UpdateController {
         guard !didStartUpdater else { return }
         ensureSparkleInstallationCache()
 #if DEBUG
-        // UI tests need to exercise Sparkle's permission request deterministically.
-        // Clearing these defaults causes Sparkle to re-request permission on next start.
+        // Keep the permission-related defaults resettable for UI tests even though the
+        // delegate now suppresses Sparkle's permission UI entirely.
         if ProcessInfo.processInfo.environment["CMUX_UI_TEST_RESET_SPARKLE_PERMISSION"] == "1" {
             let defaults = UserDefaults.standard
             defaults.removeObject(forKey: "SUEnableAutomaticChecks")
@@ -71,13 +71,9 @@ class UpdateController {
         }
 #endif
         do {
-            // cmux never enables automatic update checks; we rely on the in-app update pill.
-            // Sparkle reads these from defaults, but set them explicitly before starting.
-            let defaults = UserDefaults.standard
-            defaults.set(false, forKey: "SUEnableAutomaticChecks")
-            defaults.set(false, forKey: "SUSendProfileInfo")
-            defaults.set(false, forKey: "SUAutomaticallyUpdate")
-
+            updater.automaticallyChecksForUpdates = true
+            updater.automaticallyDownloadsUpdates = false
+            updater.sendsSystemProfile = false
             try updater.start()
             didStartUpdater = true
         } catch {
@@ -201,7 +197,7 @@ class UpdateController {
     /// Validate the check for updates menu item.
     func validateMenuItem(_ item: NSMenuItem) -> Bool {
         if item.action == #selector(checkForUpdates) {
-            // Always allow user-initiated checks; we start Sparkle lazily on first use.
+            // Always allow user-initiated checks; Sparkle can safely surface current progress.
             return true
         }
         return true

Sources/Update/UpdateDelegate.swift

@@ -13,6 +13,10 @@ enum UpdateFeedResolver {
 }
 
 extension UpdateDriver: SPUUpdaterDelegate {
+    func updaterShouldPromptForPermissionToCheck(forUpdates _: SPUUpdater) -> Bool {
+        false
+    }
+
     func feedURLString(for updater: SPUUpdater) -> String? {
 #if DEBUG
         let env = ProcessInfo.processInfo.environment
@@ -35,6 +39,7 @@ extension UpdateDriver: SPUUpdaterDelegate {
     /// Called when an update is scheduled to install silently,
     /// which occurs when automatic download is enabled.
     func updater(_ updater: SPUUpdater, willInstallUpdateOnQuit item: SUAppcastItem, immediateInstallationBlock immediateInstallHandler: @escaping () -> Void) -> Bool {
+        viewModel.clearDetectedUpdate()
         viewModel.state = .installing(.init(
             isAutoUpdate: true,
             retryTerminatingApplication: immediateInstallHandler,
@@ -56,6 +61,7 @@ extension UpdateDriver: SPUUpdaterDelegate {
     }
 
     func updater(_ updater: SPUUpdater, didFindValidUpdate item: SUAppcastItem) {
+        viewModel.recordDetectedUpdate(item)
         let version = item.displayVersionString
         let fileURL = item.fileURL?.absoluteString ?? ""
         if fileURL.isEmpty {
@@ -66,6 +72,7 @@ extension UpdateDriver: SPUUpdaterDelegate {
     }
 
     func updaterDidNotFindUpdate(_ updater: SPUUpdater, error: Error) {
+        viewModel.clearDetectedUpdate()
         let nsError = error as NSError
         let reasonValue = (nsError.userInfo[SPUNoUpdateFoundReasonKey] as? NSNumber)?.intValue
         let reason = reasonValue.map { SPUNoUpdateFoundReason(rawValue: OSStatus($0)) } ?? nil
@@ -80,13 +87,18 @@ extension UpdateDriver: SPUUpdaterDelegate {
         }
     }
 
-    @MainActor
+    func updater(_ updater: SPUUpdater, userDidMake _: SPUUserUpdateChoice, forUpdate _: SUAppcastItem, state _: SPUUserUpdateState) {
+        viewModel.clearDetectedUpdate()
+    }
+
     func updaterWillRelaunchApplication(_ updater: SPUUpdater) {
-        AppDelegate.shared?.persistSessionForUpdateRelaunch()
-        TerminalController.shared.stop()
-        NSApp.invalidateRestorableState()
-        for window in NSApp.windows {
-            window.invalidateRestorableState()
+        Task { @MainActor in
+            AppDelegate.shared?.persistSessionForUpdateRelaunch()
+            TerminalController.shared.stop()
+            NSApp.invalidateRestorableState()
+            for window in NSApp.windows {
+                window.invalidateRestorableState()
+            }
         }
     }
 }

Sources/Update/UpdateTestSupport.swift

@@ -6,6 +6,14 @@ enum UpdateTestSupport {
     static func applyIfNeeded(to viewModel: UpdateViewModel) {
         let env = ProcessInfo.processInfo.environment
         guard env["CMUX_UI_TEST_MODE"] == "1" else { return }
+
+        if let detectedVersion = env["CMUX_UI_TEST_DETECTED_UPDATE_VERSION"],
+           !detectedVersion.isEmpty {
+            DispatchQueue.main.async {
+                viewModel.detectedUpdateVersion = UpdateViewModel.normalizedDetectedUpdateVersion(from: detectedVersion)
+            }
+        }
+
         guard let state = env["CMUX_UI_TEST_UPDATE_STATE"] else { return }
 
         DispatchQueue.main.async {

Sources/Update/UpdateViewModel.swift

@@ -6,6 +6,7 @@ import Sparkle
 class UpdateViewModel: ObservableObject {
     @Published var state: UpdateState = .idle
     @Published var overrideState: UpdateState?
+    @Published var detectedUpdateVersion: String?
     #if DEBUG
     @Published var debugOverrideText: String?
     #endif
@@ -14,6 +15,14 @@ class UpdateViewModel: ObservableObject {
         overrideState ?? state
     }
 
+    func recordDetectedUpdate(_ item: SUAppcastItem) {
+        detectedUpdateVersion = Self.normalizedDetectedUpdateVersion(from: item.displayVersionString)
+    }
+
+    func clearDetectedUpdate() {
+        detectedUpdateVersion = nil
+    }
+
     var text: String {
         #if DEBUG
         if let debugOverrideText { return debugOverrideText }
@@ -334,6 +343,11 @@ class UpdateViewModel: ObservableObject {
             return nil
         }
     }
+
+    static func normalizedDetectedUpdateVersion(from version: String) -> String? {
+        let trimmed = version.trimmingCharacters(in: .whitespacesAndNewlines)
+        return trimmed.isEmpty ? nil : trimmed
+    }
 }
 
 enum UpdateState: Equatable {