Opened 6 years ago

Closed 5 years ago

Last modified 5 years ago

#29139 closed Bug (fixed)

Aggregate functions failing when using Postgres JSON field KeyTransform

Reported by: trik Owned by: ddio
Component: contrib.postgres Version: 2.2
Severity: Normal Keywords: json keytransform unhashable
Cc: Triage Stage: Accepted
Has patch: yes Needs documentation: no
Needs tests: no Patch needs improvement: yes
Easy pickings: no UI/UX: no


When annotating by a nested KeyTransform applied to a JSON field, aggregate functions fail:

JSONModel.objects.annotate(history=KeyTransform('-1', 'field'))\
    .annotate(last_state=KeyTransform('state', 'history'))\

JSONModel.objects.annotate(history=KeyTransform('-1', 'field'))\
    .annotate(last_state=KeyTransform('state', 'history'))\
Traceback (most recent call last):
  File "/Users/trik/Projects/3d_party/django/tests/postgres_tests/", line 305, in test_keytransform
  File "/Users/trik/Projects/3d_party/django/django/db/models/", line 384, in count
    return self.query.get_count(using=self.db)
  File "/Users/trik/Projects/3d_party/django/django/db/models/sql/", line 494, in get_count
    number = obj.get_aggregation(using, ['__count'])['__count']
  File "/Users/trik/Projects/3d_party/django/django/db/models/sql/", line 462, in get_aggregation
    outer_query.add_subquery(inner_query, using)
  File "/Users/trik/Projects/3d_party/django/django/db/models/sql/", 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/", 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/", line 55, in pre_sql_setup
    group_by = self.get_group_by( + extra_select, order_by)
  File "/Users/trik/Projects/3d_party/django/django/db/models/sql/", line 130, in get_group_by
    if (sql, tuple(params)) not in seen:
TypeError: unhashable type: 'list'

Failing test case

Change History (9)

comment:1 by Tim Graham, 6 years ago

Triage Stage: UnreviewedAccepted

Similar exception as #28762 but the fix there doesn't resolve this.

comment:2 by Piotr Domański, 6 years ago

Owner: set to Piotr Domański
Status: newassigned

comment:3 by Piotr Domański, 6 years ago

Owner: Piotr Domański removed
Status: assignednew

comment:4 by ddio, 6 years ago

Owner: set to ddio
Status: newassigned

I resolved this issue when digging into nested KeyTransform.

Root Cause

  1. When using nested KeyTransform, it concatenate child keys in the wrong format, i.e. a list [child1, child2]
  2. Instead, according to pgsql, it should be a string like '{child1, child2, ...}'


After updating the as_sql() transformation, the issue is resolved. Will send PR soon.

Last edited 6 years ago by ddio (previous) (diff)

comment:5 by Tim Graham, 6 years ago

Has patch: set
Patch needs improvement: set

PR (with improvements noted)

comment:6 by Tim Graham, 5 years ago

I closed #29139 as a duplicate but that could be confirmed if a patch is provided.

Version 0, edited 5 years ago by Tim Graham (next)

comment:7 by Mariusz Felisiak <felisiak.mariusz@…>, 5 years ago

Resolution: fixed
Status: assignedclosed

In d87bd29:

Fixed #30335, #29139 -- Fixed crash when ordering or aggregating over a nested JSONField key transform.

comment:8 by Mariusz Felisiak, 5 years ago

Version: 2.02.2

comment:9 by Mariusz Felisiak <felisiak.mariusz@…>, 5 years ago

In e85317d7:

[2.2.x] Fixed #30335, #29139 -- Fixed crash when ordering or aggregating over a nested JSONField key transform.

Backport of d87bd29c4f8dfcdf3f4a4eb8340e6770a2416fe3 from master.

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