Re: newline cache

[Eli Zaretskii <eliz@gnu.org>]

> Date: Mon, 21 Apr 2014 12:28:03 -0400
> From: Richard Stallman <rms@gnu.org>
> 
> I recall that some months ago I encountered a bug in the newline cache
> which caused mail-fetch-field to include a extra newline in the value
> of the X-RMAIL-ATTRIBUTES field.  ISTR that the bug was fixed.
> 
> But it happened again, in Emacs as rebuilt on March 19 from fairly
> recent sources.
> 
> There was little hope I can find a way to reproduce it from a
> standing start -- I could hardly hope to get the newline cache just
> right.
> 
> Does anyone remember what the fix was for that bug?

I've seen a couple of problems in the current pretest which
disappeared once I turned off the cache in the Rmail buffer.  I've
tried to see what does Rmail do that triggers this, but came up
empty-handed.  Help is welcome.

In general, each insertion and each deletion in any buffer must call
invalidate_buffer_caches.  I tried to find any code that doesn't, but
couldn't find anything.

Another possibility is that the tricky optimizations in find_newline
have some subtle bug, so close scrutiny of that code might find the
cause.