Zed freezes when editing Rust code

[road2react]

Summary

Zed freezes when editing Rust code and is stuck at 100% CPU usage

Steps to trigger the problem:

1. I cannot find a consistent reproduction

Actual Behavior:

Zed freezes and becomes unresponsive, and is stuck at 100% CPU usage with increasing memory.

Recorded by samply when frozen:

profile.json (doesn't contain symbols, but they come from Arch Linux debug servers, with Zed installed from official repository)

Zed Version and System Specs

Zed: v0.172.8 (Zed)
OS: Linux Wayland arch unknown
Memory: 93.5 GiB
Architecture: x86_64
GPU: AMD Radeon 680M (RADV REMBRANDT) || radv || Mesa 24.3.4-arch1.1

[maxbrunsfeld]

@SomeoneToIgnore It looks like a lot of time being spent in InlayHintCache::new_update_task. Could you look into this?

[SomeoneToIgnore]

I'm afraid it's looping there without end, but I'm not certain how to trigger that, will try to look at the code better.

Meanwhile, if anyone experiencing that could get RPC messages that Zed receives from rust-analyzer, it would help a lot with the fix:

[road2react]

@SomeoneToIgnore

Meanwhile, if anyone experiencing that could get RPC messages that Zed receives from rust-analyzer, it would help a lot with the fix:

How to access the logs when the editor is frozen? Are they saved to a file?

[SomeoneToIgnore]

Good point, they are not accessible then.
But if you can trigger this reliably, can you share a project and a way to repro this?

[road2react]

I killed rust-analyzer processes but the editor was still mostly frozen. I can however get a click response in every few seconds, which moves the text cursor but then freezes again.

New flamegraph:

profile.json

[SomeoneToIgnore]

That's all pretty clear from the original trace — we're stuck in the hint traversal.
More interesting question is how to repro this, as I've never got this, unfortunately.

What kind of settings do you have for inlay hints?

[ggueyraud]

I have a similar issue on PopOs 22.04, Zed 0.173.x (don't know exactly which minor version, I write this message from my config) and rust 1.85
In my cast that freeze the screen, then black screen for few seconds and then it nothing respond (it's like basicly the OS crash).
How can I give you informations that can help to solve this issue ? At the moment I use macos instead but it's not convenient as PopOs in my opinion

[SomeoneToIgnore]

What's discussed here is not OS-dependent, it's a cross-platform inlay hints' storage code that malfunctions.

I'm interested in the inlay hint-related settings (maybe, on PopOs you have a different config?) and a project where I can try to reproduce this in, ideally with some sequence of actions described.

[ggueyraud]

How can I have the "inlay hint-related settings"?
I don't know if that's not OS depend because for a same codebase it crash on PopOS but not on MacOS. Unfortunatly I cannot give you access it's a commercial project
Please ask if I can give you any others informations that could help you to investigate this issue.

[SomeoneToIgnore]

Are we talking about the same thing here?
Nothing crashes in the OP, it hangs.

For the hint settings, interested to see if anything from Zed settings

zed/assets/settings/default.json

Lines 386 to 404 in 4871d3c

	"inlay_hints": {
	// Global switch to toggle hints on and off, switched off by default.
	"enabled": false,
	// Toggle certain types of hints on and off, all switched on by default.
	"show_type_hints": true,
	"show_parameter_hints": true,
	// Corresponds to null/None LSP hint type value.
	"show_other_hints": true,
	// Whether to show a background for inlay hints.
	//
	// If set to `true`, the background will use the `hint.background` color from the current theme.
	"show_background": false,
	// Time to wait after editing the buffer, before requesting the hints,
	// set to 0 to disable debouncing.
	"edit_debounce_ms": 700,
	// Time to wait after scrolling the buffer, before requesting the hints,
	// set to 0 to disable debouncing.
	"scroll_debounce_ms": 50
	},

or LSP setting https://zed.dev/docs/languages/rust#inlay-hints is different between OSes you use.

If nothing's different, this is quite unexpected to see, but good pointer, I will try to find a Linux machine to use things on and see how it behaves for me.

[SomeoneToIgnore]

After testing it for a few days on Fedora, I'm not sure that it's entirely platform-related, as I had no hangs while using hints extensively (as usual).

Another possibility could be rust-analyzer installations?
I use rust-analyzer releases, published on https://github.com/rust-lang/rust-analyzer/releases every Monday.

Could be so that a particular, older, one is used on PopOS and causes Zed to hang?
Using

command will allow to open the language server info tab with the data to check and copy for sharing: