bug#46400: [BISECTED] Sporadically breaking newline-indentation in c-mode

[Konstantin Kharlamov <hi-angel@yandex.ru>]

On Fri, 2021-02-12 at 14:56 +0000, Alan Mackenzie wrote:
> Hello, Konstantin.
> 
> First of all, thanks for taking the trouble to report this bug, and
> thanks even more for taking the diagnosis so far.
> 
> On Fri, Feb 12, 2021 at 17:08:19 +0300, Konstantin Kharlamov wrote:
> > On Wed, 2021-02-10 at 01:13 +0300, Konstantin Kharlamov wrote:
> > > I just bisected it to a commit 
> 
> > >     3096437593 CC Mode: introduce a new cache for brace structures.  This
> > > fixes bug #45248
> 
> > > before this commit I couldn't reproduce it, and on this I reproduce it
> > > immediately.
> 
> > > CCing the commit author.
> 
> > So, what's the plan here? Should I send a revert?
> 
> No, please don't do that - that was an essential fix for a performance
> bug.
> 
> > CC: Alan Mackenzie (I know I already CCed, but I figured they might
> > not know they were mentioned if they has mail filters for example,
> > since I didn't write the name).
> 
> Sorry, I should have got back to you sooner, but I wanted to have
> something to show.
> 
> I don't think the bug was introduced by the commit you cite, more likely
> that commit triggered the bug which was lying in wait elsewhere.
> 
> I've been working on this bug for several hours, so far, and have found
> that the "c-state-cache" (which records the positions of certain braces,
> brackets and parentheses) becomes corrupt while running your `test'
> function.  I'm trying to track down where and how this corruption
> happens.
> 
> Also relevant is that the bug seems to be being triggered by the
> apostrophe in
> 
>     bar("Couldn't open %s", to);
>                ^
> 
> ..  At least, if I take that apostrophe away, I don't see the bug
> symptoms any more.
> 
> So, please bear with me some while longer.  I am working on the bug.
> 

D: Oh, this is cool! Sure, thank you very much for looking into it! I'm definitely not in hurry, I was just kinda being afraid that the report could've gotten through the cracks. I'm happy to hear that wasn't the case ☺