Give user more flymake control

[Dickby]

eglot seems to totally ignore the state of flymake-mode, disabling it changes nothing inside the eglot-managed buffer.
Further the varibale flymake-no-changes-timeout is a floating point number,
but it seems eglot just uses it like a boolean, setting it to nil disables automatic checking,
every other value just acts as t.

[joaotavora]

See this commit message and related issues for a discussion of why flymake-no-changes-timeout cannot be honoured in the traditional way: 2b87b06

eglot seems to totally ignore the state of flymake-mode, disabling it changes nothing inside the eglot-managed buffer.

What are you trying to achieve? Do you want to not use flymake? Then see variable eglot-stay-out-of.

[joaotavora]

The comment I linked to explains why what you're trying to do is currently impossible with LSP (as far as I know). The LSP spec does not specify a way to request diagnostics "on demand". This is an essential primitive operation to get the behaviour you're looking for. Instead, an LSP server provides them "when it sees fit": usually -- but not always -- after it is informed of changes in the file. So unless the LSP spec has changed in that regard (it might have, maybe someone knows), I'm afraid your use case cannot be implemented.

[Dickby]

Thanks for the information.
I try to hack around that then.

[joaotavora]

Let us know how it goes.

[Dickby]

if i set flymake-no-changes-timeout to nil, is flymake still using eglot's informations for the check if i run flymake-start ?

[joaotavora]

Yes. That's what the commit message I linked to says.

[Dickby]

Sorry i didn't understand it from that, my bad.
But in that case this is what works for me:

  (setq flymake-no-changes-timeout nil)
  (add-hook 'c-mode-hook (lambda()
			   (setq-local my/flymake-idle (run-with-idle-timer 2 t 'flymake-start))
			   (add-hook 'kill-buffer-hook (lambda()
							 (when (timerp my/flymake-idle )
							   (cancel-timer my/flymake-idle))) 0 t)))

[joaotavora]

Alright, as I wrote in #957, you may be lucky with that strategy or you may be not. If the LSP server takes, say, 2.1 seconds to deliver diagnostics to the client after being informed of changed, then you'll always be one step behind. And that time depends on the project size etc. So I don't think this is a a general solution. But if it works for you and your project, great!

[Dickby]

Isn't there a way to tell when the last time the server delivered diagnostics, and run flymake only if that has happend during the idle time?

[Dickby]

Now that i tried a bit: my solution is not optimal either.
It's nice that i can control when flycheck gets the results of the changes presented to the lsp-server.
But I think for custom tweaking it would be really good to be able to control when eglot sends the changes to the server.
Depending on the users configuration, there could be nice ways to set it up.
For evil-mode for example it could nicely be controled by the evil-state changes.

[Dickby]

I see it is mentioned there too.
Thanks
feel free to close this issue