bug#24074: bug#24094: 25.1.50; revert-buffer error in CC mode

[Óscar Fuentes]

Alan Mackenzie <acm@muc.de> writes:

> Could you be a bit more descriptive about the "chunks" that are missing,
> please?  Are we talking about lots of isolated 2-character chunks, or
> just one or two larger chunks, or what?  Are the chunks at the end of a
> buffer, or in the "middle" of it?

It just happened again here. The missing chunk is everything below the
first 9 lines (the file has ~400 lines). Those preserved lines are
simply #include's. The final preserved line was truncated to

#include <

The original was

#include <string.h>

Prior the revert, the point was much below that 9nth line.

The reported failure is not always the same. In this case was:

c-determine-+ve-limit: Args out of range: #<buffer rawmem.cpp>, -7246, -6746


Or course, now that I'm trying to cause the error for obtaining an stack
trace, it doesn't happen :-( As mentioned on my bug report, it seems
that the problem is triggered when the point falls on certain places
on the reverted file's contents, but that's just my guess.