Non-C-style comments are filled incorrectly

[NateEag]

Consider the following set of comments:

// This is a test comment. If I get it to go a very long way, my autowrapping will work, but you will find that Meta-Q will
// not fill the comment correctly.

# What happens when I write a lengthy comment prefixed by the # symbol? I am not sure, but I guess I am about to find out.

/* However, something very similar will actually work exactly the way you would expect it to in a C-style comment. Any ideas why this is?
 */

All three are correctly highlighted as comments by php-mode.

However, if you use Meta-Q to wrap the comments, only the last comment is filled correctly. The first two are wrapped, but no comment prefix is inserted at the beginning of the new lines.

[ejmr]

What version of Emacs and php-mode are you using?

M-q works for the first and third comments for me, although when I M-q the first there is a brief moment where Flymake thinks the code is in error. But it still adds the // prefix.

The second comment screws up on M-q for me in the same way it does for you.

[NateEag]

I'm using Aquamacs 2.4, which is built on Emacs 23.3.50.1.

My php-mode.el has the following version info in it:

(defconst php-mode-version-number "1.10"
  "PHP Mode version number.")

(defconst php-mode-modified "2013-02-15"
  "PHP Mode build date.")

I believe it is current master (I use subtree merging to pull it into my .emacs.d, which is a git repo).

[ejmr]

I believe it is current master...

It is. Thanks for the info. I have no access to a computer which Aquamacs but I'll try getting a friend to see if he can duplicate it.

[NateEag]

I just tried firing up an instance of Emacs 24, freshly downloaded from Emacs for OS X, and in Emacs 24, I see the behavior you describe.

So, that difference is probably a discrepancy between Emacs 23 and 24.

[ejmr]

Here's what I've figured out so far, just in case anyone else whats to pitch in.

I started looking at the code in sh-script.el.gz because it handles comments beginning with # in the way we want for php-mode. It gives the # character a slightly different syntax class, but when I tried copying that in php-mode it did not work. That mode also sets the local variable comment-start to the string "# ", but I doubt we want to do this either. The shell script mode has the benefit of only dealing with one style of comments, while we have to support three.

But I still feel like some tweaking to the syntax class of # is the solution to this. I just haven't exactly figured it out yet.

[NateEag]

Thanks very much for looking into this.

Maybe looking at C++-mode's innards would help? Filling both /*- and //-style comments works as expected there, so it might give useful hints on how to handle #, too.

[ejmr]

Thanks very much for looking into this.

No problem, it's my job. :)

Maybe looking at C++-mode's innards would help?

That's a good idea. I'll check it out.

[tigerhawkvok]

Maybe a hacky way to approach this would be to see if a fill was triggered on a #-style comment, then if so, manually prefix the line for now?

[ejmr]

Like (defadvice c-fill-paragraph ...)? That could be a viable band aid.

[metaturso]

@NateEag I've found that all three styles of comment can be indented correctly after you evaluate this form:

;; this is the relevant bit, you'll notice it's adding # as a comment start char
(setq-local comment-start-skip "\\(//+\\|#+\\|/[*]\\{1,2\\}\\)\\s *") 

I'll write a php-mode test and raise a PR this weekend if you're happy with the fix. In the meanwhile you can solve the problem by adding that configuration to your php-mode-hook.

Here's a gif showing the behaviour of Emacs 24.5.1 before and after evaluating the form above:

[NateEag]

@trashofmasters I am not actively using php-mode these days, but thanks for the info. Glad to hear you've found a workaround for this.

[zonuexe]

I wasn't aware of this issue, but maybe https://github.com/emacs-php/php-mode/pull/530/files seems to fix this issue. Thanks for reporting!

[NateEag]

You're very welcome. Thanks for your years of faithful maintenance, @zonuexe !