eglot with ccls: M-. can only find and jump to func definitions if they are in buffers

[renzhengeek]

Hi all,
I'm excited that eglot+ccls works for my C project (linux kernel). It's much more convenient than TAGS, but after a while I found it fails to find func definitions that is not in current buffer, or not in other buffers (opened C/header files).

My config for c-mode in init.el:

(add-hook 'c-mode-hook 'eglot-ensure)                                                                                
                                                                                                                     
;(defun projectile-project-find-function (dir)                                                                       
;  (let* ((root (projectile-project-root dir)))                                                                      
;    (and root (cons 'transient root))))                                                                             
;(with-eval-after-load 'project                                                                                      
;  (add-to-list 'project-find-functions 'projectile-project-find-function)) 

I commented out projectile functions, otherwise emacs reports error that projectile-project-root is void.
According to ccls eglot doc:https://github.com/MaskRay/ccls/wiki/eglot), ccls defaults to use builtin project, so I think it probably doesn't matter.

I googled a lot, still fails to solve the problem. Am I missing something? Please help give some directions:-) Thanks!

[joaotavora]

I believe this is a problem with ccls and @MaskRay could help you with that. As an Eglot issue, this is missing many elements pointed to by the template that you probably deleted. I've reworked that template: if you try to create a new issue in Eglot you should be presented with more clear instructions on how to make an issue that I can help you with. It'll help you find the Events transcript and other important elements. Until then, I'm going to close this one, but we can keep discussing.

[MaskRay]

The likely issue is that you do not provide a compile_commands.json/.ccls so ccls does not know the initial set of files to index.
If neither compile_commands.json nor .ccls is provided, ccls can only find cross references for files where textDocument/open has been sent.

That seems like a usage error, unrelated to eglot.

[joaotavora]

Thanks @MaskRay.

[renzhengeek]

@joaotavora Thanks! Will try @MaskRay 's suggestion later:-)

[renzhengeek]

Hello @MaskRay ,

If neither compile_commands.json nor .ccls is provided, ccls can only find cross references for files where textDocument/open has been sent.

I'm very new to eglot and ccls. Is there any link to explain what they are and how to configure/make them?

That seems like a usage error, unrelated to eglot.

Thanks! But, I do follow the doc: https://github.com/MaskRay/ccls/wiki/eglot

[renzhengeek]

I'm very new to eglot and ccls. Is there any link to explain what they are and how to configure/make them?
Aha, found and reading this doc:

https://github.com/MaskRay/ccls/wiki/Project-Setup#ccls-file

[renzhengeek]

See: https://github.com/MaskRay/ccls/wiki/Project-Setup#ccls-examples
The .ccls config solves my problem:

clang
%c -std=c11
%cpp -std=c++2a
%h %hpp --include=Global.h
-Iinc
-DMACRO

Thanks!