Re: Fwd: Bug#1018950: gettext-el: warnings when po-mode.el is compiled with GNU Emacs 28

[Bruno Haible]

Hello Santiago, Vincent,

> Here are the details of the warnings (note that the compilation of
> the other .el files does not yield any warning; this is specific
> to po-mode.el):
> 
> In toplevel form:
> po-mode.el:180:2: Warning: custom-declare-variable `po-highlight-face' 
> docstring has wrong usage of unescaped single quotes (use \= or different 
> quoting)

This type of warning will not be fixed. It's explained in
<https://lists.gnu.org/archive/html/emacs-devel/2022-07/msg00663.html>
<https://emacs.stackexchange.com/questions/73047/>
that to fix this, every ' needs to be replaced with a quadrigraph \\=' .
The point of this warning is to make the doc string ugly in the source file
so that it becomes pretty when displayed in a certain way in Emacs.

However, for po-mode.el, *no one* views these doc strings in Emacs.
The maintainer — that's me — views them in the source code, outside Emacs.
Therefore it would be a disgrace to make the doc strings more ugly in the
source code.

> In po-mode:
> po-mode.el:1068:14: Warning: ‘write-contents-hooks’ is an obsolete variable 
> (as of 22.1); use ‘write-contents-functions’ instead.

Fixed through
https://git.savannah.gnu.org/gitweb/?p=gettext.git;a=commitdiff;h=7793b37d96e1e343585fd37c19612fcffa3aa035

> In po-set-msgstr-form:
> po-mode.el:2114:13: Warning: (lambda nil \...) quoted with ' rather than with 
> #'

Referring to <https://emacs.stackexchange.com/questions/74318/>, the point of
this warning is to allow the Emacs compiler to compile this lambda.
But this is not necessary here, since it's a hook function (rarely invoked)
and may invoke functions that are not present at compile-time.

> In po-show-source-context:
> po-mode.el:2570:4: Warning: ‘goto-line’ is for interactive use only; use 
> ‘forward-line’ instead.

According to <https://stackoverflow.com/questions/11805572/>
  "the reason why goto-line should not be a frequently used command
   is that normally there's no reason to want to get to line number N
   unless you have a program that told you there's something interesting
   on that line."
But that's precisely the case here: The PO file contains a reference
to source line number N. Therefore goto-line is the right thing here.

> In po-tags-search:
> po-mode.el:2639:10: Warning: ‘tags-loop-continue’ is an obsolete function (as 
> of 27.1); use ‘fileloop-continue’ instead.
> po-mode.el:2643:8: Warning: ‘tags-loop-continue’ is an obsolete function (as 
> of 27.1); use ‘fileloop-continue’ instead.

fileloop-continue does not exist in Emacs 26 or older. However, po-mode supports
Emacs 22 or newer. Therefore nothing to be done here.

> In po-tags-loop-operate:
> po-mode.el:2703:12: Warning: Use ‘with-current-buffer’ rather than 
> save-excursion+set-buffer
> 
> In po-mark-found-string:
> po-mode.el:2724:6: Warning: Use ‘with-current-buffer’ rather than 
> save-excursion+set-buffer

The Emacs documentation at
https://www.gnu.org/software/emacs/manual/html_node/elisp/Current-Buffer.html
does not state that there would any problem with 'set-buffer'. It just presents
'with-current-buffer' as an alternative.

As long as it's not broken, I won't change it.

> In end of data:
> po-mode.el:2110:4: Warning: the function ‘ediff-quit’ is not known to be 
> defined.

False alarm. 'ediff-quit' is only used once ediff mode is entered.

Bruno