Union operation not producing OGC valid shapes

[bretttully]

Start with 4 boxes that once unioned, produce a hole that touches the exterior contour. Even with ogc in the overlay options, this produces a single exterior contour rather than an exterior and interior contour.

I'll have a PR up shortly, that at least includes a test, and hopefully a suggested fix.

[NailxSharipov]

Thanks for the tests! I’ve opened PR #59 with my own fix; it resolves this without increasing algorithmic complexity.

[NailxSharipov]

Thanks for the patch and tests. I've reviewed it. A solution is correct but it can be done without increasing algorithmic complexity in a linear time.

I moved your tests to my pr #59

[bretttully]

Awesome, thanks @NailxSharipov !!

Do you mind getting this fix released,? Then I can raise a pr in geo. Thanks

[NailxSharipov]

Thanks for your help. I've released 4.4.0 with all updates included.