Fix ESC k title payload rendering

lib/terminal.test.ts

@@ -79,6 +79,21 @@ function expectEchoRender(
   expect(renderArgs[0][1]).toBe(false);
 }
 
+/**
+ * Helper to get visible text for a terminal row.
+ */
+function getTerminalLineText(term: Terminal, y: number): string {
+  const line = term.wasmTerm?.getLine(y);
+  if (!line) {
+    throw new Error(`Unable to read terminal line ${y}`);
+  }
+
+  return line
+    .map((cell) => String.fromCodePoint(cell.codepoint || 32))
+    .join('')
+    .trimEnd();
+}
+
 describe('Terminal', () => {
   let container: HTMLElement;
 
@@ -939,6 +954,107 @@ describe('onKey event', () => {
   });
 });
 
+describe('GNU screen/tmux title sequences', () => {
+  const issueReproSequence = '\x1bk/tmp\x1b\\\r\n\x1bkls\x1b\\demo.txt\r\n';
+  let container: HTMLElement | null = null;
+
+  beforeEach(async () => {
+    if (typeof document !== 'undefined') {
+      container = document.createElement('div');
+      document.body.appendChild(container);
+    }
+  });
+
+  afterEach(() => {
+    if (container && container.parentNode) {
+      container.parentNode.removeChild(container);
+      container = null;
+    }
+  });
+
+  test('ESC k title payload is ignored for string writes', async () => {
+    const term = await createIsolatedTerminal({ cols: 80, rows: 24 });
+    if (!container) return;
+    term.open(container);
+
+    try {
+      term.write(issueReproSequence);
+
+      expect(getTerminalLineText(term, 0)).toBe('');
+      expect(getTerminalLineText(term, 1)).toBe('demo.txt');
+    } finally {
+      term.dispose();
+    }
+  });
+
+  test('ESC k title payload is ignored for BEL-terminated string writes', async () => {
+    const term = await createIsolatedTerminal({ cols: 80, rows: 24 });
+    if (!container) return;
+    term.open(container);
+
+    try {
+      term.write('\x1bkfoo\x07bar\r\n');
+
+      expect(getTerminalLineText(term, 0)).toBe('bar');
+    } finally {
+      term.dispose();
+    }
+  });
+
+  test('ESC k title payload is ignored for 8-bit ST-terminated Uint8Array writes', async () => {
+    const term = await createIsolatedTerminal({ cols: 80, rows: 24 });
+    if (!container) return;
+    term.open(container);
+
+    try {
+      term.write(
+        new Uint8Array([0x1b, 0x6b, 0x66, 0x6f, 0x6f, 0x9c, 0x62, 0x61, 0x72, 0x0d, 0x0a])
+      );
+
+      expect(getTerminalLineText(term, 0)).toBe('bar');
+    } finally {
+      term.dispose();
+    }
+  });
+
+  test('ESC k title payload is ignored for Uint8Array writes', async () => {
+    const term = await createIsolatedTerminal({ cols: 80, rows: 24 });
+    if (!container) return;
+    term.open(container);
+
+    try {
+      term.write(new TextEncoder().encode(issueReproSequence));
+
+      expect(getTerminalLineText(term, 0)).toBe('');
+      expect(getTerminalLineText(term, 1)).toBe('demo.txt');
+    } finally {
+      term.dispose();
+    }
+  });
+
+  test('ESC k title payload remains ignored across split writes', async () => {
+    const term = await createIsolatedTerminal({ cols: 80, rows: 24 });
+    if (!container) return;
+    term.open(container);
+
+    try {
+      term.write('\x1b');
+      term.write('k/tmp');
+      term.write('\x1b');
+      term.write('\\\r\n');
+      term.write('\x1b');
+      term.write('kls');
+      term.write('\x1b');
+      term.write('\\demo.txt\r\n');
+
+      expect(getTerminalLineText(term, 0)).toBe('');
+      expect(getTerminalLineText(term, 1)).toBe('demo.txt');
+    } finally {
+      term.dispose();
+    }
+  });
+});
+
 describe('onTitleChange event', () => {
   let container: HTMLElement | null = null;
 

patches/ghostty-wasm-api.patch

@@ -1593,6 +1593,58 @@ index ba2af2473..b8be8f273 100644
 +            // preserving the backing cell offset and dirty state.
 +            row.* = .{ .cells = cells_offset, .dirty = dirty };
          }
+diff --git a/src/terminal/Parser.zig b/src/terminal/Parser.zig
+index 980906e49..c175d9d5b 100644
+--- a/src/terminal/Parser.zig
++++ b/src/terminal/Parser.zig
+@@ -27,6 +27,7 @@ pub const State = enum {
+     dcs_ignore,
+     osc_string,
+     sos_pm_apc_string,
++    screen_title_string,
+ };
+
+ /// Transition action is an action that can be taken during a state
+diff --git a/src/terminal/parse_table.zig b/src/terminal/parse_table.zig
+index 01bd569cb..fe6701794 100644
+--- a/src/terminal/parse_table.zig
++++ b/src/terminal/parse_table.zig
+@@ -148,6 +148,10 @@ fn genTable() Table {
+         // => dcs_entry
+         single(&result, 0x50, source, .dcs_entry, .none);
+
++        // GNU screen/tmux title sequence: ESC k <text> ST/BEL
++        // Consume payload so it never reaches the visible grid.
++        single(&result, 0x6B, source, .screen_title_string, .none);
++
+         // => csi_entry
+         single(&result, 0x5B, source, .csi_entry, .none);
+
+@@ -324,6 +328,24 @@ fn genTable() Table {
+         range(&result, 0x3C, 0x3F, source, .csi_param, .collect);
+     }
+
++    // screen_title_string
++    {
++        const source = State.screen_title_string;
++
++        // events
++        single(&result, 0x19, source, source, .ignore);
++        range(&result, 0, 0x06, source, source, .ignore);
++        range(&result, 0x08, 0x17, source, source, .ignore);
++        range(&result, 0x1C, 0x1F, source, source, .ignore);
++        range(&result, 0x20, 0xFF, source, source, .ignore);
++        single(&result, 0x7F, source, source, .ignore);
++
++        // Accept BEL and the 8-bit ST terminator explicitly; ESC \\ exits
++        // through the existing anywhere ESC transition.
++        single(&result, 0x07, source, .ground, .none);
++        single(&result, 0x9C, source, .ground, .none);
++    }
++
+     // osc_string
+     {
+         const source = State.osc_string;
 diff --git a/src/terminal/render.zig b/src/terminal/render.zig
 index b6430ea34..10e0ef79d 100644
 --- a/src/terminal/render.zig