input: crash binding can configure which thread to crash

src/Surface.zig

@@ -3673,7 +3673,19 @@ pub fn performBindingAction(self: *Surface, action: input.Binding.Action) !bool
 
         .quit => try self.app.setQuit(),
 
-        .crash => @panic("crash binding action, crashing intentionally"),
+        .crash => |location| switch (location) {
+            .main => @panic("crash binding action, crashing intentionally"),
+
+            .render => {
+                _ = self.renderer_thread.mailbox.push(.{ .crash = {} }, .{ .forever = {} });
+                self.queueRender() catch |err| {
+                    // Not a big deal if this fails.
+                    log.warn("failed to notify renderer of crash message err={}", .{err});
+                };
+            },
+
+            .io => self.io.queueMessage(.{ .crash = {} }, .unlocked),
+        },
 
         .adjust_selection => |direction| {
             self.renderer_state.mutex.lock();

src/input/Binding.zig

@@ -300,12 +300,27 @@ pub const Action = union(enum) {
     /// Quit ghostty.
     quit: void,
 
-    /// Crash ghostty. This is funny, but is used for testing crash handling.
+    /// Crash ghostty in the desired thread for the focused surface.
-    /// It is shipped in production builds because sometimes we need to
+    ///
-    /// test crash handling works for a user who may have some specific
+    /// WARNING: This is a hard crash (panic) and data can be lost.
-    /// configuration. This is not bound by default and I recommend not
+    ///
-    /// binding it.
+    /// The purpose of this action is to test crash handling. For some
-    crash: void,
+    /// users, it may be useful to test crash reporting functionality in
+    /// order to determine if it all works as expected.
+    ///
+    /// The value determines the crash location:
+    ///
+    ///   - "main" - crash on the main (GUI) thread.
+    ///   - "io" - crash on the IO thread for the focused surface.
+    ///   - "render" - crash on the render thread for the focused surface.
+    ///
+    crash: CrashThread,
+
+    pub const CrashThread = enum {
+        main,
+        io,
+        render,
+    };
 
     pub const CursorKey = struct {
         normal: []const u8,

src/renderer/Thread.zig

@@ -270,6 +270,8 @@ fn drainMailbox(self: *Thread) !void {
     while (self.mailbox.pop()) |message| {
         log.debug("mailbox message={}", .{message});
         switch (message) {
+            .crash => @panic("crash request, crashing intentionally"),
+
             .visible => |v| {
                 // Set our visible state
                 self.flags.visible = v;

src/renderer/message.zig

@@ -8,6 +8,10 @@ const terminal = @import("../terminal/main.zig");
 
 /// The messages that can be sent to a renderer thread.
 pub const Message = union(enum) {
+    /// Purposely crash the renderer. This is used for testing and debugging.
+    /// See the "crash" binding action.
+    crash: void,
+
     /// A change in state in the window focus that this renderer is
     /// rendering within. This is only sent when a change is detected so
     /// the renderer is expected to handle all of these.

src/termio/Thread.zig

@@ -268,6 +268,7 @@ fn drainMailbox(
 
         log.debug("mailbox message={}", .{message});
         switch (message) {
+            .crash => @panic("crash request, crashing intentionally"),
             .change_config => |config| {
                 defer config.alloc.destroy(config.ptr);
                 try io.changeConfig(data, config.ptr);

src/termio/message.zig

@@ -29,6 +29,10 @@ pub const Message = union(enum) {
         padding: renderer.Padding,
     };
 
+    /// Purposely crash the renderer. This is used for testing and debugging.
+    /// See the "crash" binding action.
+    crash: void,
+
     /// The derived configuration to update the implementation with. This
     /// is allocated via the allocator and is expected to be freed when done.
     change_config: struct {