change in the result of polygon-line intersection from versions 3.8.1 to v3.9.0

[davemfish]

Apologies for not having a pure geos example. I observe a change in the result of a polygon-line intersection from geos versions 3.8.1 to 3.9.0. My shapely version is the same in both environments (1.7.1)

from shapely.geometry import Polygon, LineString
poly = Polygon(((-200, -200), (200, -200), (200, 200), (-200, 200), (-200, -200)))
line = LineString([(-100, 100), (-100, -100)])
print(poly.intersects(line))                       # always True
print(poly.intersection(line).wkt)                 # LINESTRING EMPTY in version 3.9.0

The intersection is LINESTRING EMPTY according to version 3.9.0, but is LINESTRING (-100 100, -100 -100) according to version 3.8.1.

I'm not entirely sure, is this a bugfix or a regression?

[pramsey]

It's a bug, gotta trust my lying eyes. Also confirm this behaviour is happening also on my copy of GEOS, which is state-of-the-art.

[davemfish]

Thanks for the confirmation. And thanks for GEOS!

[dr-jts]

Fixed in JTS.
Fixed in GEOS 3.10 (e30955844d).
Backported to GEOS 3.9