Re: master c4d34d2: CC Mode: Enhance C++ Mode raw strings to multi-line strings for any language

[Alan Mackenzie <acm@muc.de>]

Hello, Lars and Basil.

On Fri, Aug 20, 2021 at 10:48:04 +0000, Alan Mackenzie wrote:
[ .... ]

> The problem is a bug in c-point-syntax.  There, there is
>   (i) an invocation of c-save-buffer-state, which binds buffer-undo-list
>   to t, followed by
>   (ii) an invocation of c-tentative-buffer-changes, which pushes nil onto
>   buffer-undo-list (simulating an undo group) giving (nil t).
>   (iii) A { is typed into the buffer, giving buffer-undo-list now as
>   something like ((5128 . 5129) nil t).
> At this point garbage collection occurs.  This strips the tail of
> buffer-undo-list, leaving ((5128 . 5129)).
>   (iv) In c-tnt-chng-cleanup, primitive-undo is repeated infinitely,
>   since buffer-undo-list will never become the expected value (nil t).

> The problem would appear to be the invalid value ((5128 . 5129) nil t) in
> buffer-undo-list.

> I'll see what I can do about this tonight.

I've just committed a patch to master which I think fixes the problem.

Thanks especially to Basil for exceptionally helpful debugging info.

> > -- 
> > Basil

-- 
Alan Mackenzie (Nuremberg, Germany).