Re: Nested display strings

[Chong Yidong]

Stefan Monnier <address@hidden> writes:

>>> So I think the best behavior is to detect the situation and signal
>>> some kind of warning/error (and behave in whichever way is most
>>> convenient for the C code).
>> I don't think there is a non-obnoxious way for redisplay to emit errors
>> or warnings in such a situation.
>
> It's tricky, indeed since redisplay will be performed repeatedly an will
> tend to signal such warnings over and over again.  A good/natural way
> for redisplay to signal such problems would be to display them directly
> in the window (e.g. insert some threatening question mark or some such,
> ideally with mouse-over highlighting and a help-echo-like text
> explaining the problem).

If such redisplay warnings are really important (which I'm still not
sure about), we could provide a Lisp-callable "debug-redisplay" built-in
command that triggers one single redisplay, accumulates all warning
messages, and puts them into a buffer afterwards.  Except when this
command is running, such redisplay warning would have no effect.  This
would help a developer who is, say, debugging a troublesome overlay,
without annoying users in other contexts.