AttributeError when using filter argument with Collect in GeoDjango Aggregate

[Olivier Le Thanh Duong]

When using the django.contrib.gis.db.models.aggregates.Collect aggregate function in GeoDjango, a AttributeError is raised when a filter argument is passed. The error is in GeoAggregate so I believe it affect all the other GeoAggregate: MakeLine, Union, Extend and Extent3D

Reproduction Steps:

1. Define the Form and Submission models as follows:

   from django.contrib.gis.db.models import PointField
   from django.db import models
   
   class Form(models.Model):
       name = models.TextField()
   
   class Submission(models.Model):
       location = PointField()
       name = models.ForeignKey(Form, on_delete=models.CASCADE)
       deleted = models.BooleanField(default=False)
   

2. Execute the following query to annotate the submission_center using Collect, applying a filter to only include undeleted submissions:

   Form.objects.annotate(submission_locations=Collect('submission__location', filter=Q(deleted=False)))
   

Expected Result:
The query should execute successfully, annotating the submission_center field in the Form model with the collected locations of undeleted submissions.

Actual Result:
An AttributeError is raised with the following traceback:

File ~/.virtualenvs/iaso/lib/python3.8/site-packages/django/contrib/gis/db/models/aggregates.py:44, in GeoAggregate.resolve_expression(self, query, allow_joins, reuse, summarize, for_save)
     42 c = super().resolve_expression(query, allow_joins, reuse, summarize, for_save)
     43 for expr in c.get_source_expressions():
---> 44     if not hasattr(expr.field, 'geom_type'):
     45         raise ValueError('Geospatial aggregates only allowed on geometry fields.')
     46 return c

AttributeError: 'WhereNode' object has no attribute 'field'

Versions Affected:
This issue can be reproduced on Django versions 3.2.15 and the main branch (1136aa5005f0ae70fea12796b7e37d6f027b9263 of 3 June). The Git log suggests that this problem exists in all versions between the reported ones.

I have a the working of a patch and will open a corresponding pull request in GitHub

[Olivier Le Thanh Duong]

Corresponding Pull request: ​https://github.com/django/django/pull/16939

[Claude Paroz]

Good catch!

[Mariusz Felisiak <felisiak.mariusz@…>]

In c1cff3c4:

Refs #34629 -- Changed SDOAGGRTYPE wrapping to Func() in GIS aggregates on Oracle.

[Mariusz Felisiak <felisiak.mariusz@…>]

In 1b754d63:

Fixed #34629 -- Added filtering support to GIS aggregates.