bug#62216: Odd file corruption in clojure mode and emacs 30 HEAD

[Eli Zaretskii <eliz@gnu.org>]

> Date: Thu, 16 Mar 2023 00:01:12 +0000
> From: Jonathon McKitrick <jcm@SDF.ORG>
> 
> I realize this is vague, but I'm seeing it consistently:
> 
> I build emacs 30 with native compilation on my M1, and I open my work clojure project, and I see rainbow parens marking a bunch of unmatched parens.
> The file will not compile, and the corruption happens simply when I open the file.
> 
> I do the exact same thing with emacs 29 built the same way, and I have no issues.
> 
> How can I narrow this down to a useful bug report?

Thanks for asking, and for the bug report in the first place.

The way to narrow this down is start with "emacs -Q", add only those
of your customizations necessary for reproducing the problem, then
post the results in the form of step by step description of the
reproduction recipe.  It will help a lot if you also post the file
which gets corrupted, both before and after the corruption.  If that
file can be small, that's preferable.

I'm guessing that you use some third-party packages, at least for
editing clojure sources.  In that case, include in your description
the packages one should download to reproduce the issue.

A description of the recipe should, therefore, look something like the
following:

  . download and install the following packages:
    - foo
    - bar
    - ...
  . start "emacs -Q"
  . type the following commands:
    - M-x load-library RET foo RET
    - M-x load-library RET bar RET
    - M-x set-variable RET foo-some-var RET t RET
    -...
  . visit the attached file foobar.clj
  . do <something> to trigger the corrption
  . observe the changes in the file's contents:
    - <description of the corruptions>

TIA