A hook to latex-mode doesn't trigger eglot ensure

[maikol-solis]

Hi!

I'm using doom-emacs, and I want to trigger eglot in latex mode automatically. I have this in my config:

(add-hook! '(latex-mode-hook
               markdown-mode-hook
               prog-mode-hook) #'eglot-ensure)

However, it doesn't work.

Checking a little of the eglot code, my best guess is in this line it's missing latex-mode. This way, eglot can find the mode correctly.

https://github.com/emacs-straight/eglot/blob/978497f4ba22373f7ef3c0ce3008d945bda98430/eglot.el#L266

Best.

[joaotavora]

latex-mode derived from tex-mode so that line shouldn't need to be there. Please read this:

https://joaotavora.github.io/eglot/#Starting-Eglot

Especially the second part. Try with M-x eglot first, and if that doesn't work, give me more information that I can use. I don't use Doom, sorry :-)

[joaotavora]

The most likely cause for your problem is that Emacs cant' find the executables to any of the servers listed for text-mode & friends in eglot-server-programs. They should be in your exec-path (which is derived from PATH when Emacs started). If you do not want them in PATH and you want to use eglot-ensure ,you have to adjust eglot-server-programs so that it knows the full pathname to the LSP server program.

[maikol-solis]

Running M-x eglot works as expected. The problem is that I can't start eglot automatically when I open a .tex file.

[joaotavora]

I don't know what your configuration looks like, but look in *Messages* for warnings. Then try again after setting debug-on-error to t with M-x toggle-debug-on-error.

[maikol-solis]

Using the default setting didn't trigger any warning or error.

However, I tried this

(add-to-list 'eglot-server-programs
             '(latex-mode . ("texlab")))

And now eglot is triggered automatically by the add-hook part.

I am just random guessing here (I don't know the internals in latex-mode). But, maybe the problem is when tex-mode is called, the default mode for the file is latex-mode and at this point there isn't any server assigned for that mode. So eglot skipped it in the eglot-server-programs list.

In any case, the line I showed before solves the problem.

Thanks.

[joaotavora]

Using the default setting didn't trigger any warning or error.

So what you meant by "it doesn't work" remains a mystery.

I am just random guessing here

Indeed you are, and so am I given the lack of info, but I've just installed texlab and this runs fine:

src/emacs -Q --eval "(add-hook 'latex-mode-hook 'eglot-ensure)" ~/tmp/coiso.tex

🤷‍♂️

[maikol-solis]

So what you meant by "it doesn't work" remains a mystery.

In my case, the problem is that eglot-ensure isn't trigger automatically when I put it into the hook.

Indeed you are, and so am I given the lack of info, but I've just installed texlab and this runs fine:

In that case, maybe is something related to doom-emacs. I will ask them if they could put this line, (add-to-list 'eglot-server-programs '(latex-mode . ("texlab"))) into the eglot module to catch any issue with {latex,tex}-mode.

Again, thanks for your support and help to figure this out.

Best.

[joaotavora]

In my case, the problem is that eglot-ensure isn't trigger automatically when I put it into the hook.

The only logical consequence of the interpretation of this is that the major mode hook doesn't run. If that were true, it would be a pretty big hole in Emacs. So I think there is some grey area on whatever you mean by "triggered". Functions in Elisp are "called", and you can even make Emacs stop when that happens with with M-x toggle-debug-on-entry RET <function-name> RET

In that case, maybe is something related to doom-emacs. I will ask them if they could put this line, (add-to-list 'eglot-server-programs '(latex-mode . ("texlab"))) into the eglot module to catch any issue with {latex,tex}-mode.

Maybe, but that's that's not catching the issue: that is hiding it. latex-mode derives from tex-mode and this is should be enough (and it is, at least in a configuration-less Emacs)

[maikol-solis]

Yes, I understand what you mean. I don't know what's causing this in that case.

Just a reference, lsp-mode calls latex-mode in the client's definition, and for me, it works out-the-box,

https://github.com/emacs-lsp/lsp-mode/blob/9292d7dbe14078cec5ffd5bb39a38d6204c227d6/clients/lsp-tex.el#L59-L63

And, as you said, it could be something deeper inside the {tex,latex}-mode.

[mmarshall540]

Wild guess, but did you have AUCTeX installed? I had the same problem and found this question while looking for a solution. At first, the only way I could get Eglot to start was to uninstall AUCTeX. So I ended up looking through the code to find out what's going on.

Turns out that AUCTeX replaces the function cells of both tex-mode and latex-mode during Emacs startup. The substituted versions of those modes don't run the original hooks. AUCTeX does this using autoloads, so bisecting your config wouldn't have caught it.

However the replaced modes do run TeX-mode-hook (case being important). So if you add eglot-ensure to TeX-mode-hook, Eglot starts as expected, even with AUCTeX installed.

[maikol-solis]

Yes, I have AUCTeX installed (by doom's setup). For me, I did this to make eglot work.

(add-hook! '(latex-mode-hook
               markdown-mode-hook
               prog-mode-hook) #'eglot-ensure)

(add-to-list 'eglot-server-programs
             '(latex-mode . ("texlab")))