bug#65380: [PATCH] Add command to copy contents in a diff-mode buffer

[Eli Zaretskii <eliz@gnu.org>]

> From: Philip Kaludercic <philipk@posteo.net>
> Cc: juri@linkov.net,  65380@debbugs.gnu.org
> Date: Mon, 19 Aug 2024 19:34:48 +0000
> 
> +*** New command 'diff-kill-ring-save'
> +This command copies out the modified contents out of a diff, without
> +having to apply it first.

This could be reworded to make the effect of the command more clear.
For example:

  This command copies to the 'kill-ring' a region of text modified
  according to diffs in the current buffer, but without applying the
  diffs to the original text.

>                            If the selected range extends a hunk, the
> +commands attempts to look up and copy the text between from the
> +referenced file.                          ^^^^^^^^^^^^^^^^^

Something is missing (or redundant) in this sentence.

> +(defun diff-kill-ring-save (beg end &optional reverse)
> +  "Save contents of the region between BEG and END akin to `kill-ring-save'.

The first line should IMO say something to make it clear this command
uses diffs from the current buffer.  OTOH, the reference to
`kill-ring-save' is much less important.  So how about

  Save to `kill-ring' the result of applying diffs in region between BEG and END.

> +By default the command will copy the text that applying the diff would
> +produce, along with the text between hunks.  If REVERSE is non-nil, or
> +the command was invoked with a prefix argument, copy the deleted text."

The "deleted text" part here is unclear: who or what deletes text and
what text is deleted?