From: Alan Mackenzie <acm@muc.de>
To: Dima Kogan <dima@secretsauce.net>
Cc: 19669@debbugs.gnu.org
Subject: bug#19669: 25.0.50; c-mode: incorrect fontification of simple enums
Date: Sun, 1 Feb 2015 17:40:57 +0000 [thread overview]
Message-ID: <20150201174057.GA2700@acm.acm> (raw)
In-Reply-To: <87a9196pdq.fsf@secretsauce.net>
Hello, Dima.
On Fri, Jan 23, 2015 at 03:36:33PM -0800, Dima Kogan wrote:
> Hi. I'm running a very recent build of emacs from git revision 253d44b
> (2015/01/08). I'm loading a very simple C file that has some enums
> defined (attached). The enum elements all should have been rendered with
> font-lock-variable-name-face
> However at startup with
> emacs -Q -nw
> only some of the elements get this face; many have just the default
> face. Pressing M-x changes things: some elements actually lose the
> correct face. In general, using emacs tends to change what is or isn't
> rendered properly. I'm attaching screenshots of the state at startup and
> after M-x.
> This is 100% reproducible on my end.
> enum xxx_xxxxxxxxxx_x
> {XXX_XXXX_XXXX_XXXXX_XXXXX,
> XXX_XXXX_XXXX_XXXXX_XXXXX,
> XXX_XXXX_XXXXXX_XXXXXXXX_XXXXXXX,
> XXX_XXXX_XXXXXX_XXXXXXXX_XXXXXXX,
> XXX_XXXX_XXXX_XXXXXXXX,
> XXXXXX_XXXXXXX_XXXX_XXXXXXXX,
> XXXXX_XXXXXX_XXXX_XXXXXXXX,
> XXX_XXXXXXX,
> XXX_XXX_XXXXXXXX,
> XXX_XXX_XXX_XXXXXXXXX,
> XXXXXX_XXX_XXXXXXX,
> X_XXXXXXXXXX};
> enum xxx_xxxx_xxxxxxxxxx_x
> {XXX_XXXXXX_XXXX_XXX,
> XXX_XXXXXX_XXXX_XX,
> XXX_XXXXXXXX_XXXX_XXX,
> XXX_XXXX_XXXXXXX,
> XXX_XX_XXXXX_XXXX_XXXXXXX,
> XXXXXX_XXXXXX_XXXX_XXXXXXXX,
> XXX_XXXX_XXXXXXX,
> // xxx
> XXXXXX_XXXXXXXX};
What is triggering this bug is the fact you have the first enum element,
"XXX_XXXX_XXXX_XXXXX_XXXXX", on the same line as the "{".
On redisplay, CC Mode calculates a syntactically critical point, here the
beginning of "XXX_XXXX_XXXX_XXXXX_XXXXX" and requests fontification
starting there. Font lock, however, decides to start fontification,
instead, at the BEGINNING OF THE LINE, which here is outside the "{",
hence things go wrong.
The solution is to remove the function from
`font-lock-extend-region-functions' which does this.
Please try out the following patch, and confirm that is does indeed solve
the problem (or tell me what isn't yet fixed).
Thanks for such a high quality bug report!
diff -r 33a71629ac14 cc-mode.el
--- a/cc-mode.el Sun Jan 11 22:37:23 2015 +0000
+++ b/cc-mode.el Sun Feb 01 17:34:19 2015 +0000
@@ -1242,6 +1242,14 @@
(font-lock-mark-block-function
. c-mark-function)))
+ ;; Prevent `font-lock-default-fontify-region' extending the region it will
+ ;; fontify to whole lines by removing `font-lock-extend-region-whole-lines'
+ ;; (and, coincidentally, `font-lock-extend-region-multiline' (which we do
+ ;; not need)) from `font-lock-extend-region-functions'. (Emacs only). This
+ ;; fixes Emacs bug #19669.
+ (when (boundp 'font-lock-extend-region-functions)
+ (setq font-lock-extend-region-functions nil))
+
(make-local-variable 'font-lock-fontify-region-function)
(setq font-lock-fontify-region-function 'c-font-lock-fontify-region)
--
Alan Mackenzie (Nuremberg, Germany).
next prev parent reply other threads:[~2015-02-01 17:40 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-23 23:36 bug#19669: 25.0.50; c-mode: incorrect fontification of simple enums Dima Kogan
[not found] ` <handler.19669.B.14220562124798.ack@debbugs.gnu.org>
2015-01-24 5:29 ` bug#19669: Acknowledgement (25.0.50; c-mode: incorrect fontification of simple enums) Dima Kogan
2015-01-24 15:27 ` Alan Mackenzie
2015-02-01 21:27 ` Alan Mackenzie
2015-02-01 17:40 ` Alan Mackenzie [this message]
2015-02-01 20:13 ` bug#19669: 25.0.50; c-mode: incorrect fontification of simple enums Dima Kogan
2015-02-01 21:58 ` Alan Mackenzie
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