bug#26328: 26.0.50; checkdoc action for join lines drops final "

[Noam Postavsky]

>> Suggestion for a fix:
>>
>> modified   lisp/emacs-lisp/checkdoc.el
>> @@ -1520,7 +1520,7 @@ checkdoc-this-string-valid-engine
>>                       ;; They said yes.  We have more fill work to do...
>>                       (goto-char (match-beginning 1))
>>                       (delete-region (point) (match-end 1))
>> -                     (insert "\n")
>> +                     (insert "\"")
>>                       (setq msg nil))))))
>>         (if msg
>>             (checkdoc-create-error msg s (save-excursion
>
> The " at the end of the doc string is removed by that `delete-region',
> so it's all a bit confusing.  The following patch also fixes the problem
> in this example, but I'm not quite sure what the code is attempting to
> do here.
>
> Anybody familiar with this code?
>
> diff --git a/lisp/emacs-lisp/checkdoc.el b/lisp/emacs-lisp/checkdoc.el
> index 830743f5f8..7ac557711a 100644
> --- a/lisp/emacs-lisp/checkdoc.el
> +++ b/lisp/emacs-lisp/checkdoc.el
> @@ -1498,12 +1498,7 @@ checkdoc-this-string-valid-engine
>                       p (1+ p)
>                       "1st line not a complete sentence.  Join these lines? "
>                       " " t)
> -                    (progn
> -                      ;; They said yes.  We have more fill work to do...
> -                      (goto-char (match-beginning 1))
> -                      (delete-region (point) (match-end 1))
> -                      (insert "\n")
> -                      (setq msg nil))))))
> +                    (setq msg nil)))))
>          (if msg
>              (checkdoc-create-error msg s (save-excursion
>                                             (goto-char s)

AFAICT, both proposed patches will do the wrong thing for this case:

    (defun foo ()
      "Bla bla
    bla bla.  More words
    bla bla bla.")