Add a configurable keyboard shortcut to open the diff viewer

Packages/CmuxSettings/Sources/CmuxSettings/Values/ShortcutAction+Defaults.swift

@@ -69,6 +69,7 @@ extension ShortcutAction {
         case .focusTextBoxInput: return ShortcutStroke(key: "a", command: true, shift: true)
         case .attachTextBoxFile: return ShortcutStroke(key: "a", command: true, shift: true, option: true)
         case .toggleRightSidebar: return ShortcutStroke(key: "b", command: true, option: true)
+        case .openDiffViewer: return ShortcutStroke(key: "d", command: true, shift: true, control: true)
         case .saveFilePreview: return ShortcutStroke(key: "s", command: true)
         case .openBrowser: return ShortcutStroke(key: "l", command: true, shift: true)
         case .focusBrowserAddressBar: return ShortcutStroke(key: "l", command: true)

Packages/CmuxSettings/Sources/CmuxSettings/Values/ShortcutAction.swift

@@ -78,6 +78,7 @@ public enum ShortcutAction: String, CaseIterable, Sendable, Hashable, SettingCod
     case toggleRightSidebar = "toggleFileExplorer"
 
     // MARK: Browser & Find
+    case openDiffViewer
     case saveFilePreview
     case openBrowser
     case focusBrowserAddressBar
@@ -145,7 +146,7 @@ extension ShortcutAction {
              .toggleSplitZoom, .equalizeSplits, .splitBrowserRight, .splitBrowserDown,
              .toggleRightSidebar:
             return .panes
-        case .saveFilePreview, .openBrowser, .focusBrowserAddressBar, .browserBack,
+        case .openDiffViewer, .saveFilePreview, .openBrowser, .focusBrowserAddressBar, .browserBack,
              .browserForward, .browserReload, .browserZoomIn, .browserZoomOut,
              .browserZoomReset, .markdownZoomIn, .markdownZoomOut, .markdownZoomReset,
              .find, .findInDirectory, .findNext, .findPrevious,
@@ -216,6 +217,7 @@ extension ShortcutAction {
         case .splitBrowserRight: return "Split Browser Right"
         case .splitBrowserDown: return "Split Browser Down"
         case .toggleRightSidebar: return "Toggle Right Sidebar"
+        case .openDiffViewer: return "Open Diff Viewer"
         case .saveFilePreview: return "Save File Preview"
         case .openBrowser: return "Open Browser"
         case .focusBrowserAddressBar: return "Focus Address Bar"

Packages/CmuxSettingsUI/Sources/CmuxSettingsUI/Navigation/CuratedSettingEntry+Default.swift

@@ -127,7 +127,7 @@ extension Array where Element == CuratedSettingEntry {
             .init(section: .globalHotkey, id: "shortcut", title: "Show/Hide All Windows", synonyms: "global hotkey shortcut recorder key command option control"),
 
             // Keyboard shortcuts
-            .init(section: .keyboardShortcuts, id: "shortcuts", title: "Keyboard Shortcuts", synonyms: "shortcuts.bindings hotkeys keybindings key bindings commands keyboard accelerators chords cmux json"),
+            .init(section: .keyboardShortcuts, id: "shortcuts", title: "Keyboard Shortcuts", synonyms: "shortcuts.bindings hotkeys keybindings key bindings commands keyboard accelerators chords cmux json open diff viewer changes review git unstaged"),
             .init(section: .keyboardShortcuts, id: "shortcut-chords", title: "Shortcut Chords", synonyms: "tmux prefix ctrl-b control-b multi key sequence chord cmux json"),
             .init(section: .keyboardShortcuts, id: "reset-defaults", title: "Reset Default Shortcuts", synonyms: "reset restore default defaults built in builtin shortcuts hotkeys keybindings commands"),
 

Resources/Localizable.xcstrings

@@ -53,6 +53,131 @@
         }
       }
     },
+    "shortcut.openDiffViewer.label": {
+      "extractionState": "manual",
+      "localizations": {
+        "ar": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "فتح عارض الاختلافات"
+          }
+        },
+        "bs": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "Otvori preglednik razlika"
+          }
+        },
+        "da": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "Åbn diffvisning"
+          }
+        },
+        "de": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "Diff-Viewer öffnen"
+          }
+        },
+        "en": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "Open Diff Viewer"
+          }
+        },
+        "es": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "Abrir visor de diferencias"
+          }
+        },
+        "fr": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "Ouvrir la visionneuse de diff"
+          }
+        },
+        "it": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "Apri visualizzatore diff"
+          }
+        },
+        "ja": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "差分ビューアを開く"
+          }
+        },
+        "km": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "Open Diff Viewer"
+          }
+        },
+        "ko": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "Diff 뷰어 열기"
+          }
+        },
+        "nb": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "Åpne diffvisning"
+          }
+        },
+        "pl": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "Otwórz podgląd różnic"
+          }
+        },
+        "pt-BR": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "Abrir visualizador de diff"
+          }
+        },
+        "ru": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "Открыть просмотр diff"
+          }
+        },
+        "th": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "เปิดตัวดู diff"
+          }
+        },
+        "tr": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "Diff Görüntüleyiciyi Aç"
+          }
+        },
+        "uk": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "Відкрити переглядач diff"
+          }
+        },
+        "zh-Hans": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "打开差异查看器"
+          }
+        },
+        "zh-Hant": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "開啟差異檢視器"
+          }
+        }
+      }
+    },
     "command.markdownZoomIn.title": {
       "extractionState": "manual",
       "localizations": {

Sources/AppDelegate.swift

@@ -942,6 +942,10 @@ final class AppDelegate: NSObject, NSApplicationDelegate, UNUserNotificationCent
         method_exchangeImplementations(originalMethod, swizzledMethod)
     }()
 
+    /// Live `cmux diff` viewer subprocesses, keyed by pid, retained until they exit.
+    /// Declared outside `#if DEBUG` because process retention is production behavior.
+    private var diffViewerProcesses: [Int32: Process] = [:]
+
 #if DEBUG
     private var didSetupJumpUnreadUITest = false
     private var jumpUnreadFocusExpectation: (tabId: UUID, surfaceId: UUID)?
@@ -972,6 +976,10 @@ final class AppDelegate: NSObject, NSApplicationDelegate, UNUserNotificationCent
         let isFirstResponder: Bool
     }
     var debugCloseMainWindowConfirmationHandler: ((NSWindow) -> Bool)?
+    /// Test seam: when set, ``openDiffViewerForFocusedWorkspace(for:)`` invokes this
+    /// instead of spawning the bundled `cmux diff` CLI, so shortcut-dispatch tests can
+    /// assert routing without launching a subprocess.
+    var debugOpenDiffViewerHandler: (() -> Void)?
     var debugCreateMainWindowSourceIsNativeFullScreenOverride: Bool?
     // Keep debug-only windows alive when tests intentionally inject key mismatches.
     private var debugDetachedContextWindows: [NSWindow] = []
@@ -5918,6 +5926,114 @@ final class AppDelegate: NSObject, NSApplicationDelegate, UNUserNotificationCent
         }?.tabManager
     }
 
+    /// Opens the diff viewer for the focused workspace of `tabManager` by spawning the
+    /// bundled `cmux diff` CLI. This is the single shared diff-open path: both the
+    /// command-palette entry and the Open Diff Viewer keyboard shortcut funnel through
+    /// here so neither duplicates diff-open logic. Returns `false` (caller beeps) when
+    /// there is no focused workspace or the bundled CLI is missing.
+    @discardableResult
+    func openDiffViewerForFocusedWorkspace(for tabManager: TabManager?) -> Bool {
+#if DEBUG
+        if let debugOpenDiffViewerHandler {
+            debugOpenDiffViewerHandler()
+            return true
+        }
+#endif
+        guard let workspace = tabManager?.selectedWorkspace,
+              let cliURL = Bundle.main.resourceURL?.appendingPathComponent("bin/cmux"),
+              FileManager.default.isExecutableFile(atPath: cliURL.path) else {
+            return false
+        }
+        let socketPath = TerminalController.shared.activeSocketPath(
+            preferredPath: SocketControlSettings.socketPath()
+        )
+        let cwd = workspace.resolvedWorkingDirectory()
+            ?? FileManager.default.homeDirectoryForCurrentUser.path
+        return launchDiffViewerProcess(
+            cliURL: cliURL,
+            socketPath: socketPath,
+            cwd: cwd,
+            workspaceId: workspace.id,
+            surfaceId: workspace.focusedPanelId
+        )
+    }
+
+    @discardableResult
+    private func launchDiffViewerProcess(
+        cliURL: URL,
+        socketPath: String,
+        cwd: String,
+        workspaceId: UUID,
+        surfaceId: UUID?
+    ) -> Bool {
+        let process = Process()
+        process.executableURL = cliURL
+        var arguments = [
+            "--socket", socketPath,
+            "diff",
+            "--unstaged",
+            "--cwd", cwd,
+            "--workspace", workspaceId.uuidString,
+            "--focus", "true",
+        ]
+        if let surfaceId {
+            arguments.append(contentsOf: ["--surface", surfaceId.uuidString])
+        }
+        process.arguments = arguments
+        process.currentDirectoryURL = URL(fileURLWithPath: cwd, isDirectory: true)
+        var environment = ProcessInfo.processInfo.environment
+        environment["CMUX_SOCKET_PATH"] = socketPath
+        environment["CMUX_BUNDLED_CLI_PATH"] = cliURL.path
+        environment["CMUX_WORKSPACE_ID"] = workspaceId.uuidString
+        if let surfaceId {
+            environment["CMUX_SURFACE_ID"] = surfaceId.uuidString
+        }
+        environment.removeValue(forKey: "CMUX_SOCKET")
+        process.environment = environment
+        process.standardInput = FileHandle.nullDevice
+
+        let stdoutPipe = Pipe()
+        let stderrPipe = Pipe()
+        process.standardOutput = stdoutPipe
+        process.standardError = stderrPipe
+        let outputCollector = ProcessOutputCollector(stdout: stdoutPipe, stderr: stderrPipe)
+        outputCollector.start()
+        process.terminationHandler = { terminatedProcess in
+            let output = outputCollector.finish()
+            let processIdentifier = terminatedProcess.processIdentifier
+            let terminationStatus = terminatedProcess.terminationStatus
+            Task { @MainActor in
+                AppDelegate.shared?.diffViewerProcesses.removeValue(forKey: processIdentifier)
+                guard terminationStatus != 0 else { return }
+#if DEBUG
+                // Log only non-sensitive metadata: the child's stdout/stderr can echo
+                // repo paths and file contents, so report a byte count, not the text.
+                cmuxDebugLog("openDiffViewer exited status=\(terminationStatus) outputBytes=\(output.utf8.count)")
+#endif
+                NSSound.beep()
+            }
+        }
+
+        do {
+            try process.run()
+            let processIdentifier = process.processIdentifier
+            diffViewerProcesses[processIdentifier] = process
+            if !process.isRunning {
+                diffViewerProcesses.removeValue(forKey: processIdentifier)
+            }
+#if DEBUG
+            cmuxDebugLog("openDiffViewer pid=\(process.processIdentifier)")
+#endif
+            return true
+        } catch {
+            outputCollector.cancel()
+#if DEBUG
+            cmuxDebugLog("openDiffViewer failed errorType=\(type(of: error))")
+#endif
+            return false
+        }
+    }
+
     func allMainWindowTabManagersForDebug() -> [TabManager] {
         Array(mainWindowContexts.values).compactMap { context in
             resolvedWindow(for: context) == nil ? nil : context.tabManager
@@ -12773,6 +12889,16 @@ final class AppDelegate: NSObject, NSApplicationDelegate, UNUserNotificationCent
             return true
         }
 
+        if matchConfiguredShortcut(event: event, action: .openDiffViewer) {
+            // Shares the command palette's diff-open path; targets the event window's
+            // focused workspace and beeps if it can't be opened (matching the palette).
+            let manager = activeTabManagerForCommands(preferredWindow: mainWindowForShortcutEvent(event))
+            if !openDiffViewerForFocusedWorkspace(for: manager) {
+                NSSound.beep()
+            }
+            return true
+        }
+
         if matchConfiguredShortcut(event: event, action: .toggleRightSidebar) {
             // Escape AppKit's performKeyEquivalent animation context. Without
             // deferring the toggle, NSAnimationContext implicitly animates the