geodjango creating GEOS multi geometries fails after python upgrade (M1)

Question

I have an @property on a model that gets a bounding box for all the geometries associated with a dataset. This code has worked fine for a couple of years. Now, on a new M1 mac laptop, I upgraded Python (3.7.4 to 3.9.7) and the configuration of GDAL and GEOS was difficult. But as I understand, django.contrib.gis includes its own versions of those libraries. Relevent code snippets:

from django.contrib.gis.geos import GeometryCollection, MultiPoint, Point
from places.models import PlaceGeom
from datasets.models import Dataset

class Dataset(models.Model):

    fields …

    @property
    def bounds(self):
        dsgeoms=PlaceGeom.objects.values_list(‘geom’,flat=True).filter(place__dataset=self.label)

        print(tuple(dsgeoms[:2]))
        # (<Point object at 0x12ee39988>, <Point object at 0x12ee39a08>)

        gc = GeometryCollection(tuple(dsgeoms[:2]))

        return json.loads(gc.envelope.geojson) if pg_geoms.count() > 0 else None

This crashes when creating the GeometryCollection with no real clue as to why, in PyCharm: “process finished with exit code 138 (interrupted by signal 10: SIGBUS)”

in django shell: “67692 bus error ./manage.py shell”

in browser: simply quits runserver

So I simply tried the examples from the Geodjango docs at https://docs.djangoproject.com/en/2.2/ref/contrib/gis/geos/, and though the Point and LineString creation worked, GeometryCollection and MultiPoint did not, with the shell error "68483 segmentation fault ./manage.py shell"

I'm stumped, but before I try building the bbox with Shapely and multiple transformations, thought I'd ask for help

Answer 1

The answer and a patch to fix this were provided by @bpartridge on GitHub, here: https://github.com/libgeos/geos/issues/528#issuecomment-997327327

TLDR; -- Django 2.2 was lax in its call to GEOS, which earlier GEOS versions 'forgave' but later ones do not.