Unexpected divide by zero errors

I have a valid polygon that looks fine on the surface from what I can tell, but they if I try and simplify it I get a divide by error in GEOS that bubbles up to an error in python.

import numpy as np
import shapely
from shapely.wkt import loads

rawp = loads("POLYGON ((5.757315768570891 477.44961942445883, 90.77830516299935 543.8752973639498, 248.07849054369257 342.5402442964279, 464.48223238911964 241.62951691200377, 413.06565212535094 131.36631050791692, 416.62730100296994 126.80760789705967, 365.4518827373675 17.06157503979785, 361.89023385974843 21.620277650655183, 32.689759002847666 442.9776645778203, 5.757315768570891 477.44961942445883))")

def simplify(poly):
    mindist = 5
    with np.errstate(over="raise", divide="raise", invalid="raise"):
        return poly.simplify(np.sqrt(mindist), preserve_topology=True)

simplify(rawp)  # fails
simplify(shapely.set_precision(rawp, 1e-8))  # fine

Gives the following error

---------------------------------------------------------------------------
FloatingPointError                        Traceback (most recent call last)
Cell In[1], line 12
      9     with np.errstate(over="raise", divide="raise", invalid="raise"):
     10         return poly.simplify(np.sqrt(mindist), preserve_topology=True)
---> 12 simplify(rawp)  # fails
     13 simplify(shapely.set_precision(rawp, 1e-8))  # fine

Cell In[1], line 10, in simplify(poly)
      8 mindist = 5
      9 with np.errstate(over="raise", divide="raise", invalid="raise"):
---> 10     return poly.simplify(np.sqrt(mindist), preserve_topology=True)

File /opt/conda/lib/python3.10/site-packages/shapely/geometry/base.py:547, in BaseGeometry.simplify(self, tolerance, preserve_topology)
    538 def simplify(self, tolerance, preserve_topology=True):
    539     """Returns a simplified geometry produced by the Douglas-Peucker
    540     algorithm
    541 
   (...)
    545     otherwise invalid geometries.
    546     """
--> 547     return shapely.simplify(self, tolerance, preserve_topology=preserve_topology)

File /opt/conda/lib/python3.10/site-packages/shapely/decorators.py:77, in multithreading_enabled.<locals>.wrapped(*args, **kwargs)
     75     for arr in array_args:
     76         arr.flags.writeable = False
---> 77     return func(*args, **kwargs)
     78 finally:
     79     for arr, old_flag in zip(array_args, old_flags):

File /opt/conda/lib/python3.10/site-packages/shapely/constructive.py:881, in simplify(geometry, tolerance, preserve_topology, **kwargs)
    846 """Returns a simplified version of an input geometry using the
    847 Douglas-Peucker algorithm.
    848 
   (...)
    878 <POLYGON ((0 0, 0 10, 10 10, 10 0, 0 0))>
    879 """
    880 if preserve_topology:
--> 881     return lib.simplify_preserve_topology(geometry, tolerance, **kwargs)
    882 else:
    883     return lib.simplify(geometry, tolerance, **kwargs)

FloatingPointError: divide by zero encountered in simplify_preserve_topology

Start with the supplied Python reproducer and inspect shapely/geometry/base.py around BaseGeometry.simplify and shapely/constructive.py around simplify_preserve_topology. Trace how the call reaches GEOS and identify why this polygon triggers a divide-by-zero under numpy.errstate while the precision-adjusted version does not. Done means the reproducer no longer raises unexpectedly and the behavior is covered by an appropriate regression test.