add undo/redo keybindings, default them on macOS

src/Surface.zig

@@ -4337,6 +4337,18 @@ pub fn performBindingAction(self: *Surface, action: input.Binding.Action) !bool
             {},
         ),
 
+        .undo => return try self.rt_app.performAction(
+            .{ .surface = self },
+            .undo,
+            {},
+        ),
+
+        .redo => return try self.rt_app.performAction(
+            .{ .surface = self },
+            .redo,
+            {},
+        ),
+
         .select_all => {
             const sel = self.io.terminal.screen.selectAll();
             if (sel) |s| {

src/apprt/action.zig

@@ -258,6 +258,13 @@ pub const Action = union(Key) {
     /// it needs to ring the bell. This is usually a sound or visual effect.
     ring_bell,
 
+    /// Undo the last action. See the "undo" keybinding for more
+    /// details on what can and cannot be undone.
+    undo,
+
+    /// Redo the last undone action.
+    redo,
+
     check_for_updates,
 
     /// Sync with: ghostty_action_tag_e
@@ -307,6 +314,8 @@ pub const Action = union(Key) {
         config_change,
         close_window,
         ring_bell,
+        undo,
+        redo,
         check_for_updates,
     };
 

src/build/mdgen/mdgen.zig

@@ -26,7 +26,7 @@ pub fn genConfig(writer: anytype, cli: bool) !void {
         \\
     );
 
-    @setEvalBranchQuota(3000);
+    @setEvalBranchQuota(5000);
     inline for (@typeInfo(Config).@"struct".fields) |field| {
         if (field.name[0] == '_') continue;
 
@@ -94,6 +94,7 @@ pub fn genKeybindActions(writer: anytype) !void {
     const info = @typeInfo(KeybindAction);
     std.debug.assert(info == .@"union");
 
+    @setEvalBranchQuota(5000);
     inline for (info.@"union".fields) |field| {
         if (field.name[0] == '_') continue;
 

src/config/Config.zig

@@ -4898,6 +4898,18 @@ pub const Keybinds = struct {
                 .{ .key = .{ .unicode = 'q' }, .mods = .{ .super = true } },
                 .{ .quit = {} },
             );
+            try self.set.putFlags(
+                alloc,
+                .{ .key = .{ .unicode = 'z' }, .mods = .{ .super = true } },
+                .{ .undo = {} },
+                .{ .performable = true },
+            );
+            try self.set.putFlags(
+                alloc,
+                .{ .key = .{ .unicode = 'z' }, .mods = .{ .super = true, .shift = true } },
+                .{ .redo = {} },
+                .{ .performable = true },
+            );
             try self.set.putFlags(
                 alloc,
                 .{ .key = .{ .unicode = 'k' }, .mods = .{ .super = true } },

src/input/Binding.zig

@@ -655,6 +655,35 @@ pub const Action = union(enum) {
     /// Only implemented on macOS.
     check_for_updates,
 
+    /// Undo the last undoable action for the focused surface or terminal,
+    /// if possible. This can undo actions such as closing tabs or
+    /// windows.
+    ///
+    /// Not every action in Ghostty can be undone or redone. The list
+    /// of actions support undo/redo is currently limited to:
+    ///
+    ///   - New window, close window
+    ///   - New tab, close tab
+    ///   - New split, close split
+    ///
+    /// All actions are only undoable/redoable for a limited time.
+    /// For example, restoring a closed split can only be done for
+    /// some number of seconds since the split was closed. The exact
+    /// amount is configured with `TODO`.
+    ///
+    /// The undo/redo actions being limited ensures that there is
+    /// bounded memory usage over time, closed surfaces don't continue running
+    /// in the background indefinitely, and the keybinds become available
+    /// for terminal applications to use.
+    ///
+    /// Only implemented on macOS.
+    undo,
+
+    /// Redo the last undoable action for the focused surface or terminal,
+    /// if possible. See "undo" for more details on what can and cannot
+    /// be undone or redone.
+    redo,
+
     /// Quit Ghostty.
     quit,
 
@@ -991,6 +1020,8 @@ pub const Action = union(enum) {
             .toggle_secure_input,
             .toggle_command_palette,
             .reset_window_size,
+            .undo,
+            .redo,
             .crash,
             => .surface,
 

src/input/command.zig

@@ -409,6 +409,18 @@ fn actionCommands(action: Action.Key) []const Command {
             .description = "Check for updates to the application.",
         }},
 
+        .undo => comptime &.{.{
+            .action = .undo,
+            .title = "Undo",
+            .description = "Undo the last action.",
+        }},
+
+        .redo => comptime &.{.{
+            .action = .redo,
+            .title = "Redo",
+            .description = "Redo the last undone action.",
+        }},
+
         .quit => comptime &.{.{
             .action = .quit,
             .title = "Quit",