fix(cli): recover prompt_toolkit paint after tmux attach

Same-width SIGWINCH (typical tmux attach) skipped screen clear and
left previous_screen inconsistent, crashing redraw with
'cell' object has no attribute 'char'. Always clear on resize
recovery and retry _output_screen_diff with previous_screen=None
on AttributeError/TypeError.

cli.py

@@ -3614,6 +3614,58 @@ def _strip_leaked_bracketed_paste_wrappers(text: str) -> str:
     return strip_leaked_bracketed_paste_wrappers(text)
 
 
+def _hermes_call_output_screen_diff(
+    orig_osd,
+    app,
+    output,
+    screen,
+    current_pos,
+    color_depth,
+    previous_screen,
+    last_style,
+    is_done,
+    full_screen,
+    attrs_for_style_string,
+    style_string_has_style,
+    size,
+    previous_width,
+):
+    """Call prompt_toolkit ``_output_screen_diff`` with Hermes resize guards.
+
+    1. Inflate ``previous_screen.height`` when the new screen is taller so pt
+       skips the reserve-vertical-space cursor move that stamps chrome into
+       scrollback (pt #29 / Hermes #26137).
+    2. On AttributeError/TypeError from a corrupt previous paint buffer
+       (classic after tmux attach with same width), retry once with
+       ``previous_screen=None`` so pt first-paints cleanly instead of crashing
+       the event loop with ``'cell' object has no attribute 'char'``.
+    """
+    try:
+        if previous_screen is not None and hasattr(previous_screen, "height"):
+            if previous_screen.height < screen.height:
+                previous_screen.height = screen.height
+    except Exception:
+        pass
+
+    try:
+        return orig_osd(
+            app, output, screen, current_pos, color_depth,
+            previous_screen, last_style, is_done, full_screen,
+            attrs_for_style_string, style_string_has_style,
+            size, previous_width,
+        )
+    except (AttributeError, TypeError):
+        # Corrupt previous_screen / row cells after client reattach.
+        return orig_osd(
+            app, output, screen, current_pos, color_depth,
+            None,  # previous_screen → first-paint erase path
+            None,  # last_style
+            is_done, full_screen,
+            attrs_for_style_string, style_string_has_style,
+            size, 0,  # previous_width → treat as changed
+        )
+
+
 def _apply_bracketed_paste_timeout_patch() -> None:
     """Patch prompt_toolkit to recover from torn bracketed-paste sequences.
 
@@ -5162,9 +5214,14 @@ class HermesCLI(CLIAgentSetupMixin, CLICommandsMixin, CLIBillingMixin):
         # reach, leaving a duplicated status bar stranded above the live origin.
         # Ctrl+L / /redraw clears it cleanly, so route the resize path through
         # the SAME recovery: wipe the visible viewport (banner-safe — CSI 2J
-        # only, never CSI 3J) and replay the transcript so nothing is lost.
-        # Row-count-only changes skip this (no reflow → no ghost) to avoid an
-        # unnecessary full repaint.
+        # by default; CSI 3J only when display.cli_rebuild_scrollback_on_redraw
+        # is enabled) and replay the transcript so nothing is lost.
+        # Same-width SIGWINCH (tmux attach, benign focus/tab signals) is left
+        # untouched — no clear, no replay — because a 2J without replay erases
+        # the visible transcript and a replay against preserved scrollback
+        # duplicates it (#65293). The stale-previous_screen crash tmux attach
+        # used to trigger is handled by _hermes_call_output_screen_diff's
+        # retry-with-first-paint instead (#83874).
         try:
             new_width = self._get_tui_terminal_width()
         except Exception:
@@ -18110,20 +18167,20 @@ class HermesCLI(CLIAgentSetupMixin, CLICommandsMixin, CLIBillingMixin):
                     other code path's behavior.
 
                     Critical: do NOT replace a None previous_screen with
-                    a fresh Screen() — that would skip the proper
-                    reset_attributes()+erase_down() at L178-185 which
-                    fires when previous_screen is None (first-paint /
+                    a fresh Screen() on the happy path — that would skip
+                    the proper reset_attributes()+erase_down() at L178-185
+                    which fires when previous_screen is None (first-paint /
                     width-change).  Without that reset, ANSI styles
                     leak between renders.
-                    """
-                    try:
-                        if previous_screen is not None and hasattr(previous_screen, "height"):
-                            if previous_screen.height < screen.height:
-                                previous_screen.height = screen.height
-                    except Exception:
-                        pass
 
-                    return _orig_osd(
+                    Safety net: if the diff crashes with AttributeError /
+                    TypeError (corrupt previous_screen after tmux attach —
+                    "'cell' object has no attribute 'char'"), retry once
+                    with previous_screen=None so pt takes the first-paint
+                    erase path instead of wedging the event loop.
+                    """
+                    return _hermes_call_output_screen_diff(
+                        _orig_osd,
                         app, output, screen, current_pos, color_depth,
                         previous_screen, last_style, is_done, full_screen,
                         attrs_for_style_string, style_string_has_style,

tests/cli/test_cli_force_redraw.py

@@ -123,6 +123,81 @@ class TestForceFullRedraw:
         assert events[:3] == ["erase", "scrollback_wipe", "replay"]
         assert events.index("scrollback_wipe") < events.index("original_resize")
 
+    def test_same_width_sigwinch_is_left_untouched(self, bare_cli, monkeypatch):
+        """Same-width SIGWINCH (tmux attach, benign focus/tab signals) must not
+        clear the viewport or replay: a 2J without replay erases the visible
+        transcript, and a replay duplicates it (#65293). The tmux-attach
+        stale-paint crash is handled by _hermes_call_output_screen_diff's
+        retry instead (#83874)."""
+        app = MagicMock()
+        events = []
+        app.renderer.output.erase_screen.side_effect = lambda: events.append("erase")
+        app.renderer.output.write_raw.side_effect = lambda *_: events.append("scrollback_wipe")
+        original_on_resize = lambda: events.append("original_resize")
+
+        bare_cli._status_bar_suppressed_after_resize = False
+        bare_cli._last_resize_width = 120
+        monkeypatch.setattr(bare_cli, "_get_tui_terminal_width", lambda: 120)
+        monkeypatch.setattr(bare_cli, "_schedule_status_bar_unsuppress", lambda *_: None)
+        monkeypatch.setattr(cli_mod, "_replay_output_history", lambda: events.append("replay"))
+
+        bare_cli._recover_after_resize(app, original_on_resize)
+
+        assert "erase" not in events
+        assert "replay" not in events
+        assert "scrollback_wipe" not in events
+        assert events == ["original_resize"]
+        assert bare_cli._last_resize_width == 120
+        assert bare_cli._status_bar_suppressed_after_resize is True
+
+    def test_output_screen_diff_retries_on_corrupt_previous_screen(self, bare_cli):
+        """Corrupt previous_screen must not wedge the paint loop.
+
+        After tmux attach, _output_screen_diff can raise AttributeError
+        ('cell' object has no attribute 'char'). Retry with previous_screen=None.
+        """
+        calls = []
+
+        def fake_osd(
+            app, output, screen, current_pos, color_depth,
+            previous_screen, last_style, is_done, full_screen,
+            attrs_for_style_string, style_string_has_style,
+            size, previous_width,
+        ):
+            calls.append((previous_screen, previous_width, last_style))
+            if previous_screen is not None:
+                # Exact failure mode from the classic CLI event loop.
+                raise AttributeError("'cell' object has no attribute 'char'")
+            return ("ok", current_pos, last_style)
+
+        screen = MagicMock()
+        screen.height = 10
+        previous = MagicMock()
+        previous.height = 8
+
+        result = cli_mod._hermes_call_output_screen_diff(
+            fake_osd,
+            app=None,
+            output=None,
+            screen=screen,
+            current_pos=None,
+            color_depth=None,
+            previous_screen=previous,
+            last_style="style",
+            is_done=False,
+            full_screen=False,
+            attrs_for_style_string=None,
+            style_string_has_style=None,
+            size=None,
+            previous_width=80,
+        )
+
+        assert result[0] == "ok"
+        assert len(calls) == 2
+        assert calls[0][0] is previous
+        assert previous.height == 10  # height inflate still applied first
+        assert calls[1] == (None, 0, None)
+
     def test_resize_recovery_is_debounced(self, bare_cli, monkeypatch):
         timers = []
         calls = []