[Django] #36906: Oracle guard for coalescing text & varchar doesn't fathom JSONField

[Django]

#36906: Oracle guard for coalescing text & varchar doesn't fathom JSONField
-------------------------------------+-------------------------------------
Reporter: Jacob | Owner: Sarah Boyce
Walls |
Type: Bug | Status: assigned
Component: Database | Version: dev
layer (models, ORM) |
Severity: Normal | Keywords:
Triage Stage: | Has patch: 0
Unreviewed |
Needs documentation: 0 | Needs tests: 0
Patch needs improvement: 0 | Easy pickings: 0
UI/UX: 0 |
-------------------------------------+-------------------------------------
`Coalesce` has an `as_oracle()` method to make sure that `varchar` and
`NCLOB` (text) fields are not mixed. `JSONField` is also implemented as an
`NCLOB` type, so it needs to be included in the check, too.

Discovered in
https://github.com/django/django/pull/20009#discussion_r2500562079.

Rough test for demonstration purposes -- a little more realism would be
nice.

{{{#!diff
diff --git a/tests/db_functions/comparison/test_coalesce.py
b/tests/db_functions/comparison/test_coalesce.py
index b08ae742df..839954f73c 100644
--- a/tests/db_functions/comparison/test_coalesce.py
+++ b/tests/db_functions/comparison/test_coalesce.py
@@ -1,4 +1,4 @@
-from django.db.models import Subquery, TextField
+from django.db.models import JSONField, Subquery, TextField
from django.db.models.functions import Coalesce, Lower
from django.test import TestCase
from django.utils import timezone
@@ -51,6 +51,14 @@ class CoalesceTests(TestCase):
self.assertQuerySetEqual(
article.order_by("title"), [lorem_ipsum.lower()], lambda a:
a.headline
)
+ # mixed JSON and Char
+ article = Article.objects.annotate(
+ # fix this to be more realistic?
+ summary_or_metadata=Coalesce("summary", "metadata",
output_field=JSONField()),
+ )
+ self.assertQuerySetEqual(
+ article.order_by("title"), [{}], lambda a:
a.summary_or_metadata
+ )

def test_ordering(self):
Author.objects.create(name="John Smith", alias="smithj")
diff --git a/tests/db_functions/migrations/0002_create_test_models.py
b/tests/db_functions/migrations/0002_create_test_models.py
index 2fa924cbe0..7c57a1eee7 100644
--- a/tests/db_functions/migrations/0002_create_test_models.py
+++ b/tests/db_functions/migrations/0002_create_test_models.py
@@ -50,6 +50,7 @@ class Migration(migrations.Migration):
("published", models.DateTimeField(null=True,
blank=True)),
("updated", models.DateTimeField(null=True, blank=True)),
("views", models.PositiveIntegerField(default=0)),
+ ("metadata", models.JSONField(default=dict)),
],
),
migrations.CreateModel(
diff --git a/tests/db_functions/models.py b/tests/db_functions/models.py
index 45a5a027f4..7fb6200fb5 100644
--- a/tests/db_functions/models.py
+++ b/tests/db_functions/models.py
@@ -21,6 +21,7 @@ class Article(models.Model):
published = models.DateTimeField(null=True, blank=True)
updated = models.DateTimeField(null=True, blank=True)
views = models.PositiveIntegerField(default=0)
+ metadata = models.JSONField(default=dict)


class Fan(models.Model):
}}}

{{{#!py
django.db.utils.DatabaseError: ORA-00932: expression
("DB_FUNCTIONS_ARTICLE"."METADATA") is of data type NCLOB, which is
incompatible with expected data type NCHAR
Help: https://docs.oracle.com/error-help/db/ora-00932/
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/36906>
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