id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
29139	Aggregate functions failing when using Postgres JSON field KeyTransform	trik	ddio	"When annotating by a nested KeyTransform applied to a JSON field, aggregate functions fail:

{{{#!python
JSONModel.objects.annotate(history=KeyTransform('-1', 'field'))\
    .annotate(last_state=KeyTransform('state', 'history'))\
    .filter(last_state__gte=5).count()

JSONModel.objects.annotate(history=KeyTransform('-1', 'field'))\
    .annotate(last_state=KeyTransform('state', 'history'))\
    .filter(last_state__isnull=False).aggregate(Sum('last_state'))
}}}

{{{
Traceback (most recent call last):
  File ""/Users/trik/Projects/3d_party/django/tests/postgres_tests/test_json.py"", line 305, in test_keytransform
    .filter(last_state__gte=5).count(),
  File ""/Users/trik/Projects/3d_party/django/django/db/models/query.py"", line 384, in count
    return self.query.get_count(using=self.db)
  File ""/Users/trik/Projects/3d_party/django/django/db/models/sql/query.py"", line 494, in get_count
    number = obj.get_aggregation(using, ['__count'])['__count']
  File ""/Users/trik/Projects/3d_party/django/django/db/models/sql/query.py"", line 462, in get_aggregation
    outer_query.add_subquery(inner_query, using)
  File ""/Users/trik/Projects/3d_party/django/django/db/models/sql/subqueries.py"", line 193, in add_subquery
    self.subquery, self.sub_params = query.get_compiler(using).as_sql(with_col_aliases=True)
  File ""/Users/trik/Projects/3d_party/django/django/db/models/sql/compiler.py"", line 443, in as_sql
    extra_select, order_by, group_by = self.pre_sql_setup()
  File ""/Users/trik/Projects/3d_party/django/django/db/models/sql/compiler.py"", line 55, in pre_sql_setup
    group_by = self.get_group_by(self.select + extra_select, order_by)
  File ""/Users/trik/Projects/3d_party/django/django/db/models/sql/compiler.py"", line 130, in get_group_by
    if (sql, tuple(params)) not in seen:
TypeError: unhashable type: 'list'
}}}

[[https://github.com/gnucoop/django/commit/34769e05be720792e8afc2aebdac0230a77e04c0|Failing test case]]
"	Bug	closed	contrib.postgres	2.2	Normal	fixed	json keytransform unhashable		Accepted	1	0	0	1	0	0