[3.1.x] Fixed #31835 -- Dropped support for JSONField __contains lookup on Oracle.

The current implementation works only for basic examples without
supporting nested structures and doesn't follow "the general principle
that the contained object must match the containing object as to
structure and data contents, possibly after discarding some
non-matching array elements or object key/value pairs from the
containing object".
Backport of 02447fb133b53ec7d0ff068cc08f06fdf8817ef7 from master

3 files changed, 22 insertions, 20 deletions

diff --git a/django/db/models/fields/json.py b/django/db/models/fields/json.py
index edc5441799..b82c6a82e2 100644
--- a/django/db/models/fields/json.py
+++ b/django/db/models/fields/json.py
@@ -146,24 +146,7 @@ class DataContains(PostgresOperatorLookup):
         return 'JSON_CONTAINS(%s, %s)' % (lhs, rhs), params
 
     def as_oracle(self, compiler, connection):
-        if isinstance(self.rhs, KeyTransform):
-            return HasKey(self.lhs, self.rhs).as_oracle(compiler, connection)
-        lhs, lhs_params = self.process_lhs(compiler, connection)
-        params = tuple(lhs_params)
-        sql = (
-            "JSON_QUERY(%s, '$%s' WITH WRAPPER) = "
-            "JSON_QUERY('%s', '$.value' WITH WRAPPER)"
-        )
-        rhs = json.loads(self.rhs)
-        if isinstance(rhs, dict):
-            if not rhs:
-                return "DBMS_LOB.SUBSTR(%s) LIKE '{%%%%}'" % lhs, params
-            return ' AND '.join([
-                sql % (
-                    lhs, '.%s' % json.dumps(key), json.dumps({'value': value}),
-                ) for key, value in rhs.items()
-            ]), params
-        return sql % (lhs, '', json.dumps({'value': rhs})), params
+        raise NotSupportedError('contains lookup is not supported on Oracle.')
 
 
 class ContainedBy(PostgresOperatorLookup):
diff --git a/docs/topics/db/queries.txt b/docs/topics/db/queries.txt
index 2afd500e54..2528144d68 100644
--- a/docs/topics/db/queries.txt
+++ b/docs/topics/db/queries.txt
@@ -960,6 +960,10 @@ contained in the top-level of the field. For example::
     >>> Dog.objects.filter(data__contains={'breed': 'collie'})
     <QuerySet [<Dog: Meg>]>
 
+.. admonition:: Oracle
+
+    ``contains`` is not supported on Oracle.
+
 .. fieldlookup:: jsonfield.contained_by
 
 ``contained_by``
diff --git a/tests/model_fields/test_jsonfield.py b/tests/model_fields/test_jsonfield.py
index 1e92b34791..7b81f3f22c 100644
--- a/tests/model_fields/test_jsonfield.py
+++ b/tests/model_fields/test_jsonfield.py
@@ -426,6 +426,10 @@ class TestQuerying(TestCase):
             [self.objs[3], self.objs[4], self.objs[6]],
         )
 
+    @skipIf(
+        connection.vendor == 'oracle',
+        "Oracle doesn't support contains lookup.",
+    )
     def test_contains(self):
         tests = [
             ({}, self.objs[2:5] + self.objs[6:8]),
@@ -441,6 +445,17 @@ class TestQuerying(TestCase):
                 qs = NullableJSONModel.objects.filter(value__contains=value)
                 self.assertSequenceEqual(qs, expected)
 
+    @skipUnless(
+        connection.vendor == 'oracle',
+        "Oracle doesn't support contains lookup.",
+    )
+    def test_contains_unsupported(self):
+        msg = 'contains lookup is not supported on Oracle.'
+        with self.assertRaisesMessage(NotSupportedError, msg):
+            NullableJSONModel.objects.filter(
+                value__contains={'baz': {'a': 'b', 'c': 'd'}},
+            ).get()
+
     @skipUnlessDBFeature('supports_primitives_in_json_field')
     def test_contains_primitives(self):
         for value in self.primitives:
@@ -647,12 +662,12 @@ class TestQuerying(TestCase):
             ('value__baz__has_key', 'c'),
             ('value__baz__has_keys', ['a', 'c']),
             ('value__baz__has_any_keys', ['a', 'x']),
-            ('value__contains', KeyTransform('bax', 'value')),
             ('value__has_key', KeyTextTransform('foo', 'value')),
         )
-        # contained_by lookup is not supported on Oracle.
+        # contained_by and contains lookups are not supported on Oracle.
         if connection.vendor != 'oracle':
             tests += (
+                ('value__contains', KeyTransform('bax', 'value')),
                 ('value__baz__contained_by', {'a': 'b', 'c': 'd', 'e': 'f'}),
                 (
                     'value__contained_by',