Clangd worker crashes unexpectedly

[hamer0]

I'm yet to find how to reproduce this issue, however the clangd worker sometimes crashes with the error "Maximum Call Stack Size Exceeded" in the emscripten generated file clangd.mjs. This could either be an issue in the js itself or within the clangd wasm. The error occurred on the first load of the site.

Not much that can be done until I can reproduce this issue. I'll add any updates here.

[hamer0]

Here are the error logs after getting this error again. It happened on a recompile without reloading the page, although the cause still is not clear.

Note: I was wrong about where the error occurs in the original issue. It is reported as happening clangd.worker.js not clangd.mjs although there still is an error there too.

[hamer0]

Turned on detailed clangd logging with the same error and it seems like the language server doesn't completely crash this time.

Although, the stack size exceeded error log doesn't show with this, so its unlikely that this is the full story. I want to say the problem is down to the worker thread spawning, but it still isn't completely clear why this would crash the whole language server and not just the thread.

[hamer0]

Clearer view of the full clangd output and where the error occurs.

Seems to be an issue with the indexing. This process is likely recursive and therefore this may be why a stack overflow is happening.

Note that this is still only an occasional issue, it mostly indexes correctly with no error:

My only thoughts are that there could be differences in how the filesystem loads and something in that is causing a recursive call that never ends. All speculation though - further investigation is required...

[hamer0]

Clangd often crashes on the first load when running in the deployed editor. Refreshing the page and letting it relaunch seems to always resolve the issue.

The bug may be a web assembly issue where not enough memory is allocated to the process initially.

[hamer0]

Its worth noting this has been tested exclusively on Chrome.

[hamer0]

Further testing shows clangd will always crash on Chrome without dev tools open. It also seems to always run without crashing on firefox.

[hamer0]

Removing the api docs populator using the lsp prevents the error from happening on start up. The lsp will successfully launch, but will still crash soon after without dev tools open

[hamer0]

Setting intial wasm memory to the maximum size (link to code) does not resolve the issue.

[hamer0]

Clangd does not work at all on safari on Mac, regardless of whether dev console is open

compiler still works so it cannot be a general issue with wasm

Clangd crashes for a different reason in this example, but its still worth noting that clangd so far only reliably works in its current state using Firefox.