The test_rectangle_special_case failure seems to be a regression in behaviour on the GEOS side.

import matplotlib.pyplot as plt
import shapely
from shapely.plotting import plot_polygon, plot_line

polygon = shapely.Polygon(
    [
        (32.71997, -117.19310),
        (32.71997, -117.21065),
        (32.72408, -117.21065),
        (32.72408, -117.19310),
    ]
)
result = shapely.maximum_inscribed_circle(polygon)

fig, ax = plt.subplots()
plot_polygon(polygon, ax=ax)
plot_line(shapely.maximum_inscribed_circle(polygon), ax=ax, color="C1")

With GEOS 3.13.0:

With GEOS 3.14.dev main:

Actually, the images are misleading because I was not using equal aspect ratio ..

Plotting this again, you can see that both results are strictly correct (they give the same size of circle). It's only that for the purpose of "polylabel", the more centered circle might give a better result.

import matplotlib.pyplot as plt
import shapely
from shapely.plotting import plot_polygon, plot_line

polygon = shapely.Polygon(
    [
        (32.71997, -117.19310),
        (32.71997, -117.21065),
        (32.72408, -117.21065),
        (32.72408, -117.19310),
    ]
)
result = shapely.maximum_inscribed_circle(polygon)

fig, ax = plt.subplots()
plot_polygon(polygon, ax=ax)
plot_line(result, ax=ax, color="C1")
ax.set_aspect("equal")
plot_line(shapely.get_point(result, 0).buffer(result.length).boundary, ax=ax, color="C1", add_points=False)

With GEOS 3.13.0:

With GEOS 3.14.dev main:

I agree with the upstream assessment that this is a "won't fix" since the input has a non-deterministic result. The input should be changed to yield a deterministic result.

$ pixi exec -s geos=3.10.1 geosop -f wkt -a "POLYGON ((100 0, 200 200, 300 200, 300 100, 100 0))" maxInscribedCircle 0.0001
LINESTRING (238.19656372070312 138.19656372070312, 182.91793823242188 165.83587646484375)
$ pixi exec -s geos=3.13.1 geosop -f wkt -a "POLYGON ((100 0, 200 200, 300 200, 300 100, 100 0))" maxInscribedCircle 0.0001
LINESTRING (238.19656372070312 138.19656372070312, 182.91793823242188 165.83587646484375)

The input should be changed to yield a deterministic result.

Then we can also just remove the test, since it was added specifically for this rectangle corner case (#644)

Going to merge this already to have green CI on main, but happy to follow-up with either updating or removing the test