bug#37548: Implement sanitation of single-file package long description

[Stefan Kangas <stefan@marxist.se>]

Bruno Félix Rezende Ribeiro <oitofelix@gnu.org> writes:

> Hello Emacs developers,

Hi Bruno,

And thanks for your patch.

> The inlined patch implements sanitation of single-file package’s long
> description which is derived from the package’s commentary header
> section.  It removes the commentary header, the double semicolon prefix
> of each line, trailing new-lines and trailing white-space.  I think this
> is the usual practice for packages in GNU ELPA and MELPA repositories.
> Furthermore it’s aligned with the intended behavior for multi-file
> packages which is to read the long description from a README file[1] ---
> which presumably does not have commentary sections nor double semicolon
> prefixes.

I agree with the change.  However, there seems to be code duplication
here, since the same is done in package.el:

          ;; For built-in packages, get the description from the
          ;; Commentary header.
          (let ((fn (locate-file (format "%s.el" name) load-path
                                 load-file-rep-suffixes))
                (opoint (point)))
            (insert (or (lm-commentary fn) ""))
            (save-excursion
              (goto-char opoint)
              (when (re-search-forward "^;;; Commentary:\n" nil t)
                (replace-match ""))
              (while (re-search-forward "^\\(;+ ?\\)" nil t)
                (replace-match ""))))

Maybe it would make more sense to create a new function in package.el
that takes care of this?  That way we don't have the same
functionality in two places.

FWIW, I would probably prefer to base it on the code already in
package.el, since I find it a bit easier to read when the regular
expressions are split up.

Best regards,
Stefan Kangas