Unexpected Crash when performing a reopen of a "Recent Project"

[wintermi]

Check for existing issues

• Completed

Describe the bug / provide steps to reproduce it

I requested to open a "Recent Project" as shown in the below screenshot.

Zed crashed at this point

Environment

Zed: v0.119.20 (Zed)
OS: macOS 14.3.0
Memory: 16 GiB
Architecture: aarch64

If applicable, add mockups / screenshots to help explain present your vision of the feature

Apple Crash Report:

Apple Crash Report.log

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No response

[JosephTLyons]

Thanks for the crash report @wintermi

[ConradIrwin]

This looks like a crash we've been seeing with alacrity, the panic is on a background thread (number 46) running:

• std::sys_common::backtrace::__rust_begin_short_backtrace::<<alacritty_terminal::event_loop::EventLoop<alacritty_terminal::tty::unix::Pty, terminal::ZedListener>>::spawn::{closure#0}, (alacritty_terminal::event_loop::EventLoop<alacritty_terminal::tty::unix::Pty, terminal::ZedListener>, alacritty_terminal::event_loop::State)>

cc @mrnugget

[mrnugget]

Hey @wintermi! Thanks for reporting — familiar avatar, from the Ghostty discord :) I'll try to look into this tomorrow, since I can now correlate this issue with the crash report we saw. Should probably help me reproduce it.

[mrnugget]

@wintermi can you reliably reproduce this? If so, what are the steps to reproduce this? For the life of me, I can't figure out why terminal would crash. Maybe there's something specific to your terminal setup?

I'm happy to hop on a call, btw.! I vaguely remember that we're in the same timezone.

[mrnugget]

A few more follow-up questions after digging into this a bit more:

1. Just to confirm: it happens when you select the project to be opened, right? It doesn't happen when you see the dialog box to select a project?
2. Does this only happen when you open Ghostty?
3. How big is the terminal window before you open the recent project?
4. Does this happen when you comment-out your whole shell-rc file? I'm wondering whether something in how your shell starts causes the allocated PTY to die which then causes the panic here.

On (4) and leaving some breadcrums:

I had previously assumed that between this call here

zed/crates/terminal/src/terminal.rs

Lines 341 to 346 in a0582d0

	//Setup the pty...
	let pty = match tty::new(
	&pty_options,
	TerminalSize::default().into(),
	window.window_id().as_u64(),
	) {

which allocates a new PTY with openpty and this call where the crash happens

zed/crates/terminal/src/terminal.rs

Line 371 in a0582d0

let _io_thread = event_loop.spawn(); // DANGER

Nothing really happens except the openpty call. But now reading this again, I realise: quite a lot might happen! Because tty:new spawns the shell:

https://github.com/alacritty/alacritty/blob/7c046f5ae664f746c5f5a4bbe18c0e89f5702305/alacritty_terminal/src/tty/unix.rs#L197-L296

So my current theory is that: openpty works and succeeds, but then something goes wrong that makes the allocated master_fd of the PTY invalid, which then leads to .spawn crashing. Now we just need to figure out what goes wrong.

[wintermi]

@wintermi can you reliably reproduce this? If so, what are the steps to reproduce this? For the life of me, I can't figure out why terminal would crash. Maybe there's something specific to your terminal setup?

I'm happy to hop on a call, btw.! I vaguely remember that we're in the same timezone.

I have not found a way to reliably reproduce the crash, in fact so far I have only experienced it 2 out 40 attempts. Both crashed after opening a Recent Project, and both crashes happened unexpectedly, while not trying to reproduce the issue. All attempts trying to reproduce the crash from a fresh start failed.

[mrnugget]

Both crashed after opening a Recent Project

Always the same project? Or a different one?

[wintermi]

Both crashed after opening a Recent Project

Always the same project? Or a different one?

For the first crash, I was switching between 2 projects and the crash occurred after the selection of the Ghostty project. For the second crash, I was switching between 3 project and the crash did occur again on the selection of the Ghostty project.

I have however not been able to reproduce the issue since upgrading to the latest version Zed 0.119.21.

[wintermi]

A few more follow-up questions after digging into this a bit more:

1. Just to confirm: it happens when you select the project to be opened, right? It doesn't happen when you see the dialog box to select a project?

After selecting the project.

2. Does this only happen when you open Ghostty?

So far, yes.

3. How big is the terminal window before you open the recent project?

I never had the terminal window open on both crashes, or prior to the crash. I generally Cmd + Tab to use Ghostty.

4. Does this happen when you comment-out your whole shell-rc file? I'm wondering whether something in how your shell starts causes the allocated PTY to die which then causes the panic here.

As I have not opened the terminal window, I assume that the shell is never started, or does Zed always start the shell?

[mrnugget]

I never had the terminal window open on both crashes, or prior to the crash. I generally Cmd + Tab to use Ghostty.
As I have not opened the terminal window, I assume that the shell is never started, or does Zed always start the shell?

Hmmm, interesting. Zed remembers whether you had a terminal open for a given project. So if you open Ghostty in Zed, open a terminal, then close the window, then use Open recent project and select Ghostty, it should spawn with the terminal window open.

The code that caused your panic originates from the terminal-spawn code, which only gets executed when a terminal is opened. So my guess would be that when you last had the Ghostty project open, there was a terminal open, and when opening the project we restored it, which then leads to the crash.

[ConradIrwin]

This was fixed.