bug#65854: Multi-file replacement diff

[Juri Linkov <juri@linkov.net>]

> On 24/09/2023 10:36, Juri Linkov wrote:
>>>> As discussed on emacs-devel, here is the patch that implements
>>>> a standalone command that reads a list of files and replacement strings,
>>>> then shows a diff to review before applying replacements.
>>>> Also provided the Dired integration to show the replacement diff
>>>> on marked files.  Later the same function could be used
>>>> to show replacement diffs from the xref buffer and maybe
>>>> from other packages as well.
>>> Here's a counter-proposal: we were talking about a "refactoring" packages
>>> on emacs-devel, maybe a week ago. And I suggested a function that would
>>> take a list of changes (as some data) and present them using some
>>> customizable logic: the current Eglot's solution uses a diff, and I'll add
>>> an implementation that shows a tree-like buffer with checkmarks, probably.
>>>
>>> I'll be starting on this any day now ;-(
>>>
>>> So... provided this won't take too long, I would suggest your code here
>>> just focuses on creating a list of changes (those shouldn't require buffers
>>> to visit files), and then you'd be able to pass them on to
>>> 'refact-show-changes' (name under construction), which would then use the
>>> interface that the user prefers.
>>>
>>> This was we'll also consolidate the diff-generating code for features of
>>> this sort.
>> I'm not sure this complication is necessary.  The proposed patch
>> does its job already.  So more generalizations could be added later.
>
> If you are sure.
>
> I just wouldn't want to keep unnecessary defcustoms around.

Actually my point was that there is already eglot--propose-changes-as-diff.
And now with addition of multi-file-replace-as-diff you will have two cases
to generalize that would be simpler to do than with only one case.