bug#66670: [PATCH] Use buffer-local comment-continue in comment-indent-new-line

[Stefan Monnier via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

>                       ;; Recreate comment-continue from comment-start.
> -                     ;; FIXME: wrong if comment-continue was set explicitly!
>                       ;; FIXME: use prev line's continuation if available.
> -                     (comment-continue nil))
> +                     (comment-continue (if (local-variable-p 'comment-continue)
> +                                           comment-continue
> +                                         nil)))

Are you sure?  `comment-continue` is very rarely set globally.
Usually it's set buffer-locally by `comment-normalize-vars`.

> +(ert-deftest local-comment-continue-in-comment-indent-new-line ()
> +  (with-temp-buffer
> +    (setq-local comment-start "/* ")
> +    (setq-local comment-end "*/")
                               ^^
Out of symmetry, I'd have expected a SPC here.

> +    (insert "foo")
> +    (newline)
> +    (insert "bar")
> +    (forward-line -1)
> +    (end-of-line)
> +    (comment-region (point-min) (point-max))
> +    (should (equal (thing-at-point 'line) "/* foo\n"))
> +    (comment-indent-new-line)

You should also test it with that very same comment but when
`comment-start` and `comment-end` have been set to something like
"// " and "".


        Stefan