Fix crash after multiple terminal resizes

When Kakoune's terminal is shown on my laptop monitor and I plug
in my external monitor, the terminal's workspace will move to that
external monitor. When this happens, Kakoune may segfault.
There are multiple resize events (SIGWINCH) in quick succession;
it crashes because we handle SIGWINCH during rendering.

The problem happens during execution of "TerminalUI::Screen::output"
(frame #18). When we receive SIGWINCH while writing to stdout, write(2)
fails with EAGAIN, prompting us to handle pending events (See ae001a1f9
(Run EventManager whenever writing to a file descriptor would block,
2022-05-10)).  We update the screen size in check_resize() here:

	#4  Kakoune::TerminalUI::check_resize (force=<optimized out>) at terminal_ui.cc:683
	#5  Kakoune::TerminalUI::get_next_key () at terminal_ui.cc:719
	#6  operator() (__closure=0x555555984198) at terminal_ui.cc:484
	#7  std::__invoke_impl<void, Kakoune::TerminalUI::TerminalUI()::<lambda(Kakoune::FDWatcher&, Kakoune::FdEvents, Kakoune::EventMode)>&, Kakoune::FDWatcher&, Kakoune::FdEvents, Kakoune::EventMode> (__f=...) at /usr/include/c++/12.2.1/bits/invoke.h:61
	#8  std::__invoke_r<void, Kakoune::TerminalUI::TerminalUI()::<lambda(Kakoune::FDWatcher&, Kakoune::FdEvents, Kakoune::EventMode)>&, Kakoune::FDWatcher&, Kakoune::FdEvents, Kakoune::EventMode> (__fn=...) at /usr/include/c++/12.2.1/bits/invoke.h:111
	#9  std::_Function_handler<void(Kakoune::FDWatcher&, Kakoune::FdEvents, Kakoune::EventMode), Kakoune::TerminalUI::TerminalUI()::<lambda(Kakoune::FDWatcher&, Kakoune::FdEvents, Kakoune::EventMode)> >::_M_invoke(const std::_Any_data &, Kakoune::FDWatcher &, Kakoune::FdEvents &&, Kakoune::EventMode &&) (__functor=..., __args#0=..., __args#1=<optimized out>, __args#2=<optimized out>) at /usr/include/c++/12.2.1/bits/std_function.h:290
	#10 std::function<void (Kakoune::FDWatcher&, Kakoune::FdEvents, Kakoune::EventMode)>::operator()(Kakoune::FDWatcher&, Kakoune::FdEvents, Kakoune::EventMode) const (__args#2=<optimized out>, __args#1=<optimized out>,  __args#0=...) at /usr/include/c++/12.2.1/bits/std_function.h:591
	#11 Kakoune::FDWatcher::run (mode=Kakoune::EventMode::Urgent, events=<optimized out>) at event_manager.cc:28
	#12 Kakoune::EventManager::handle_next_events (mode=mode@entry=Kakoune::EventMode::Urgent, sigmask=sigmask@entry=0x0, block=<optimized out>, block@entry=false) at event_manager.cc:143
	#13 Kakoune::write (fd=1, data=...) at file.cc:273
	#14 Kakoune::BufferedWriter<4096>::flush () at string.hh:236
	#15 Kakoune::BufferedWriter<4096>::write (data="t file.hh:145
	#16 Kakoune::TerminalUI::Screen::set_face (face=..., writer=...) at terminal_ui.cc:255
	#17 operator() (line=..., __closure=<synthetic pointer>) at terminal_ui.cc:326
	#18 Kakoune::TerminalUI::Screen::output (force=force@entry=true, synchronized=<optimized out>, writer=...) at terminal_ui.cc:402
	#19 Kakoune::TerminalUI::redraw (force=force@entry=true) at terminal_ui.cc:571
	#20 Kakoune::TerminalUI::refresh (force=<optimized out>) at terminal_ui.cc:592
	#21 Kakoune::Client::redraw_ifn () at client.cc:282
	#22 Kakoune::ClientManager::redraw_clients () at client_manager.cc:232
	#23 Kakoune::run_server (session=..., server_init=..., client_init=..., init_buffer="fish-rust/src/ast.rs", init_coord=..., flags=Kakoune::ServerFlags::None, ui_type=Kakoune::UIType::Terminal,
	    debug_flags=<optimized out>, files=ArrayView<Kakoune::StringView> = {...}) at main.cc:893
	#24 main (argc=<optimized out>, argv=<optimized out>) at main.cc:1243

Thereafter, "TerminalUI::Screen::output" resumes and crashes due to
a buffer overflow in "lines" which has been resized.

0 files changed, 0 insertions, 0 deletions