Re: Assertion !is_empty() failed - yet again

[David Kastrup]

Aaron Hill <address@hidden> writes:

> On 2019-10-30 2:05 am, Rutger Hofman wrote:
>> Sincere request: can this assert please be removed? Its validity
>> appears
>> debatable, and it is a showstopper for me!
>
> If we agree that an empty interval does not have a well-defined
> center, then the assertion is quite valid.
>
> But the problematic intervals in question were never intended to ever
> be empty, yet their left and right bounds are computed in such a way
> to form degenerate, "inside-out" intervals that are treated as empty.
> The assertion properly is pointing out this flaw in computation.  As
> such, we should not be removing the assertion, because rather we
> should ensure that computations never invert the bounds of an
> interval.
>
> That said, I feel the hard-fail approach of an assertion is too
> strong, and what we need is to simply emit a warning that the function
> will be returning the midpoint of the interval's bounds despite the
> interval appearing to be invalid (read: empty).

There are lots of situations where this assertion may trigger and not
all of them may have a sensible fallback.  So one would need to see what
particular case is triggered here.

-- 
David Kastrup