Restart language servers when they crash

[tbodt]

Is your feature request related to a problem? Please describe.

I'm running into a bug in clangd that causes it to crash pretty frequently while I edit.

Describe the solution you'd like

There should be an option to automatically restart a language server that crashes (after printing a message saying it crashed, of course). I think it would also make sense for this to be the default.

Describe alternatives you've considered

I'm trying to get the clangd bug fixed, but that might take a bit.

[afnanenayet]

As an addendum, it might be fruitful to have some sort of metering on this. Say you space out restarts, so you restart after 1 second after the first crash, having the restart time increase after subsequent crashes, or some sort of limit on how many times the server gets restarted.

I'm thinking of a scenario where a langserver just keeps constantly crashing and getting restarted, which could be an issue.

[dylanirlbeck]

I second this feature request!

I think a nice alternative would be a command you can call to restart the language server --- say LanguageClient_restart(). Then you could just remap a key to this function. Just a thought.

[loonies]

Yes please - a command for restarting the server.

It happens to me almost every time due to bug/crash during a debugging session - so annoying.

[ulidtko]

+1 on this from me.

I've tried emulating it via map <Leader>r :LanguageClientStop<CR>:LanguageClientStart<CR> — but that behaves racy, doesn't work. E900: invalid channel id appears frequently.

Mild caution for the implementer: please make sure to employ exponential backoff when doing the restarts. The reason is: not all error-exits of the LSP server are crashes due to bug (plus, many of those won't be "cured" by restart — so, try to avoid making a crash loop) — in my case, the LSP server often gets too big appetite for RAM, and gets OOM-killed by the system (to prevent system stall).

It's a PITA that instead of simply hitting \r to bring it back up, I have to restart whole NVim.

[martskins]

Closing via #1113