Re: TAGS completion with (setq-local completion-ignore-case t)

[Morgan Willcock]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Morgan Willcock <morgan@ice9.digital>
>> Cc: emacs-devel@gnu.org
>> Date: Thu, 07 Mar 2024 09:54:31 +0000
>> 
>> Eli Zaretskii <eliz@gnu.org> writes:
>> 
>> >> Is there a technical reason why TAGS completion cannot use the value of
>> >> completion-ignore-case that is set in the buffer where completion is
>> >> initiated, or is this a bug in the implementation?
>> >
>> > If you mean completion when you type "M-.", then this has its own user
>> > option, tags-case-fold-search.  Is that what you want?
>> 
>> I am talking about completion as initiated by the complete-tag command.
>> 
>> (Setting tags-case-fold-search to t does not change the result, whether
>> set buffer-local or globally).
>
> Can you show a complete recipe, starting from "emacs -Q", to reproduce
> the issue?

I've included a script below which should demonstrate the problem,
i.e. no completions are generated when the buffer-local value of
completion-ignore-case is t until the value of completion-ignore-case is
also set to t for the TAGS buffer.

> And what version of Emacs is that?

I've tested on 29.2 and the master branch (as of a few hours ago).

  ## Generate a TAGS file.
  printf "Function IsSingle\nFunction IsString\n" > functions
  etags --lang=none --regex='/^function[ \t]+\([0-9A-Za-z:_]+\)/\1/i' functions


  ## Test default completion (case-sensitive).
  emacs -Q --eval "(progn \
                    (pop-to-buffer (get-buffer-create \"test\")) \
                    (visit-tags-table \"TAGS\") \
                    (insert \"Is\") \
                    (complete-tag) \
                    (complete-tag))"

  # 2 possible completions:
  # IsSingle
  # IsString


  ## Test case-insensitive completion (global).
  emacs -Q --eval "(progn \
                    (pop-to-buffer (get-buffer-create \"test\")) \
                    (setq completion-ignore-case t) \
                    (visit-tags-table \"TAGS\") \
                    (insert \"is\") \
                    (complete-tag) \
                    (complete-tag))"

  # 2 possible completions:
  # IsSingle
  # IsString


  ## Test case-insensitive completion (buffer-local).
  emacs -Q --eval "(progn \
                    (pop-to-buffer (get-buffer-create \"test\")) \
                    (setq-local completion-ignore-case t) \
                    (visit-tags-table \"TAGS\") \
                    (insert \"is\") \
                    (complete-tag) \
                    (complete-tag))"

  # No completions.


  ## Test case-insensitive completion (buffer-local, including TAGS buffer).
  emacs -Q --eval "(progn \
                    (pop-to-buffer (get-buffer-create \"test\")) \
                    (setq-local completion-ignore-case t) \
                    (visit-tags-table \"TAGS\") \
                    (with-current-buffer \"TAGS\" \
                      (setq-local completion-ignore-case t)) \
                    (insert \"is\") \
                    (complete-tag) \
                    (complete-tag))"

  # 2 possible completions:
  # IsSingle
  # IsString

-- 
Morgan Willcock