Re: cc-mode 5.31 doesn't like eval-after-load c-set-style

[Andrew M. Scott]

>>>>> "Alan" == Alan Mackenzie <address@hidden> writes:

    Alan> Hi, Andrew! On Wed, 7 Dec 2005, Andrew M. Scott wrote:
    >> FYI, I had also posted this on Dec 5th on the emacs-pretest-bug
    >> list (no response yet):
    >> http://lists.gnu.org/archive/html/emacs-pretest-bug/2005-12/msg00075.html

    Alan> Sorry! bug-cc-mode (even as a cc:) is always a better place,
You're right :-) I should have cc'd bug-cc-mode on the original report.

    >> I've had the following code snippet in my .emacs file for ages,
    >> but only recently (since cc-mode 5.31?) has it produced errors
    >> like this one. I see the issue with both a Dec 5, 2005 and Nov
    >> 2004 CVS Emacs build I had available. I also tried cc-mode
    >> 5.31.1 that I saw on sourceforge, but get the same error.

    >> % emacs -q

    >> Eval the following code snippet: (eval-after-load "cc-mode"
    >> '(progn (c-set-style "gnu") ))

    Alan> OK, that code's wrong! `c-set-style' applies to an
    Alan> individual buffer, and if you do it in the eval-after-load
    Alan> form, the current buffer is somewhat ill-defined. For
    Alan> example, if you did (load-library 'cc-mode), Bad Things
    Alan> might happen.

Thanks. This was a legacy code fragment.

    Alan> An extra check was added fairly recently to c-set-style
    Alan> because Bad Things were happening when people called it for
    Alan> non-CC Mode buffers.

Which explains why I'm just seeing the error when the cc-mode 5.31
rotation showed up. Thanks.

    Alan> Are you sure you don't really want (setq c-default-style
    Alan> "gnu"), [or even, (setq c-default-style '((java-mode .
    Alan> "java") (awk-mode . "awk")))?] You can even do this with
    Alan> customize-group <ret> c <ret>.

Yes. These are the right way to do it.

    Alan> Or is it that you've got the default style set to "linux"
    Alan> and you want the first buffer to be loaded, junk.c, to get
    Alan> "gnu"?

    >> C-x C-f junk.c

    Alan> What happens is this: this command loads junk.c, sees it
    Alan> needs c-mode, so it loads cc-mode.elc. It then tries to set
    Alan> the style "gnu" on junk.c before it's had a chance to
    Alan> initialise c-mode on it.

    Alan> The error message in this case "Buffer junk.c is not a CC
    Alan> Mode buffer" is perhaps suboptimal. Do you think "Buffer
    Alan> junk.c is not a CC Mode buffer, or hasn't been initialized
    Alan> yet" might be better?

    Alan> What exactly do you see as the bug? Is it the obscure error
    Alan> message, or do you really, really, absolutely unavoidably
    Alan> HAVE to set junk.c's style in this eval-after-load?

I think the current "error message" is sufficient. I don't think any
cc-mode or Emacs code changes are needed for this issue. The fix is for
me to use setq c-default-style or c-set-style directly.

Thanks,
Andy Scott