cider-completion-at-point-function prevents ggtags from working correctly

[achikin]

Expected behavior

ggtags jumps to definition correctly when cider repl is not connected

Actual behavior

Visit tags table (default TAGS): ... helm buffer pops up.

Steps to reproduce the problem

I can only provide reproduction steps on Spacemacs.

1. add clojure layer
2. add ggtags layer
3. restart spacemacs
4. generate tags with SPC m g c
5. open any clojure file and press SPC m g g or spacemacs/jump-to-definition

This behavior is described here: company-mode/company-mode#333 (comment)

In short this happens because company-mode can't filter out the default tags-completion-at-point-function from completion-at-point-functions list because it is made a local variable in cider-mode(and cider-repl too) here https://github.com/clojure-emacs/cider/blob/master/cider-mode.el#L1011
When I do describe-variable completion-at-point-functions inside clojure buffer I see the following:

completion-at-point-functions is a variable defined in ‘minibuffer.el’.
Its value is
(cider-complete-at-point tags-completion-at-point-function ggtags-completion-at-point)
Local in buffer distribution_templates.clj; global value is 
(tags-completion-at-point-function)

  This variable may be risky if used as a file-local variable.

Which means that when cider repl is not connected - tags-completion-at-point-function is used for completion instead of expected ggtags-completion-at-point

Environment & Version information

CIDER version information

;; CIDER 0.18.0 (Saigon), nREPL 0.2.13
;; Clojure 1.9.0, Java 1.8.0_20

Lein/Boot version

Not relevant

Emacs version

GNU Emacs 26.1

Operating system

macOS 10.14.1

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contribution and understanding!

[bbatsov]

ggtags jumps to definition correctly when cider repl is not connected

How is finding definitions related to company-mode?

In short this happens because company-mode can't filter out the default tags-completion-at-point-function from completion-at-point-functions list because it is made a local variable in cider-mode(and cider-repl too) here https://github.com/clojure-emacs/cider/blob/master/cider-mode.el#L1011

Can you create a patch for this yourself? Seems the solution is clear:

Apparently, somehow you have tags-completion-at-point-function in the local value of completion-at-point-functions, which should never happen, as long as the latter variable's value is only changed using the hook functions (such as add-hook). When it's only in the global value, we filter it out in company--capf-data-real.

I wasn't aware we were supposed to modify it via a hook, but that's a simple fix.