bug#12704: 24.2.50; QuitError during redisplay: (eval (\` ((-3 (\, (propertize "%p" ...

[Stefan Monnier <monnier@iro.umontreal.ca>]

> Are you sure that the cause was not C-g?

We have no idea.  Eli was just pointing out that a `quit' signal can
also be generated without the user hitting C-g, although it's admittedly
very unusual.  But while rendering the mode-line, inhibit-quit is
non-nil normally, so hitting C-g should presumably not signal `quit' in
your code.

> To *Messages*.  But I guess there is not, since you say that this is
> the normal handling of an eval error and did not come from C-g.
> I understand that such a message would be printed for a real (display)
> error.  What seemed odd was that it would be done for C-g during
> redisplay.  That's what I thought was happening.

The message should not be printed, because what happened is something
which shouldn't happen.  I'm not sure how best to try and track down the
source of this `quit' signal, OTOH.

The only non-negligible computation in your expression seems to be a few
calls to `current-column'
Oh, wait, there's also the "mapcar #'eval" which could potentially do
something non-trivial, so you might want to look in there, see if some
of the code run from there might let-bind inhibit-quit back to nil or if
it might signal `quit'?


        Stefan