bug#5570: automatic cache validation

[Alan Mackenzie]

Hi, Yidong and Paul!

On Wed, Apr 28, 2010 at 02:55:34PM -0400, Chong Yidong wrote:
> Hi Alan,

> I found a small recipe for reproducing a (the?) cache bug on the trunk:

> 1. emacs -Q

> 2. C-x C-f foo.c RET

> 3. Type the following (from view-lossage):

>   i n t SPC m a i n SPC ( ) <return>
>   { <return> f o o ; <return> } M-< <return>
>   <up> # i n c l u d e SPC < s t d i o . h > <return>
>   <down> <down> <down> <tab>

> At this point, the line "foo;" becomes indented to the zeroth column.

> Does this help?

Does it help?  That was an absolute dream of a bug report.  :-)

The problem was another off-by-one error.  What triggered the bug is
typing <return> at the end of the #include line.  The thing marking the
end of the macro (a category text property) got pushed onto the next line
instead of being properly removed.  This then fouled up the
"c-state-cache" mechanism.

It looks like the situation reported by Paul (in his mail of 2010-02-23,
Message-Id: <201002231528.09081.pogonyshev@gmx.net>) is likely caused by
the same bug.

I've committed a fix to the Bazaar HEAD, which of course is a fix for the
last bug in this area.  ;-)

Paul, would you please update your copy of the Emacs HEAD from savannah,
and see if any indentation bugs still manifest themselves.  Thanks!

-- 
Alan Mackenzie (Nuremberg, Germany).