remove unnecessary $literal wrapping in Value.as_mql()

It only needs to wrap integers, and wrapping over types causes incorrect
matching in ArrayField.

Author: timgraham

django_mongodb/expressions.py

@@ -204,20 +204,24 @@ def when(self, compiler, connection):
 
 def value(self, compiler, connection):  # noqa: ARG001
     value = self.value
+    if isinstance(value, int):
+        # Wrap numbers in $literal to prevent ambiguity when Value appears in
+        # $project.
+        return {"$literal": value}
     if isinstance(value, Decimal):
-        value = Decimal128(value)
-    elif isinstance(value, datetime.date):
+        return Decimal128(value)
+    if isinstance(value, datetime.date):
         # Turn dates into datetimes since BSON doesn't support dates.
-        value = datetime.datetime.combine(value, datetime.datetime.min.time())
-    elif isinstance(value, datetime.time):
+        return datetime.datetime.combine(value, datetime.datetime.min.time())
+    if isinstance(value, datetime.time):
         # Turn times into datetimes since BSON doesn't support times.
-        value = datetime.datetime.combine(datetime.datetime.min.date(), value)
-    elif isinstance(value, datetime.timedelta):
+        return datetime.datetime.combine(datetime.datetime.min.date(), value)
+    if isinstance(value, datetime.timedelta):
         # DurationField stores milliseconds rather than microseconds.
-        value /= datetime.timedelta(milliseconds=1)
-    elif isinstance(value, UUID):
-        value = value.hex
-    return {"$literal": value}
+        return value / datetime.timedelta(milliseconds=1)
+    if isinstance(value, UUID):
+        return value.hex
+    return value
 
 
 def register_expressions():

tests/expressions_/test_value.py

@@ -11,37 +11,33 @@ class ValueTests(SimpleTestCase):
     def test_date(self):
         self.assertEqual(
             Value(datetime.date(2025, 1, 1)).as_mql(None, None),
-            {"$literal": datetime.datetime(2025, 1, 1)},
+            datetime.datetime(2025, 1, 1),
         )
 
     def test_datetime(self):
         self.assertEqual(
             Value(datetime.datetime(2025, 1, 1, 9, 8, 7)).as_mql(None, None),
-            {"$literal": datetime.datetime(2025, 1, 1)},
+            datetime.datetime(2025, 1, 1),
         )
 
     def test_decimal(self):
-        self.assertEqual(Value(Decimal("1.0")).as_mql(None, None), {"$literal": Decimal128("1.0")})
+        self.assertEqual(Value(Decimal("1.0")).as_mql(None, None), Decimal128("1.0"))
 
     def test_time(self):
         self.assertEqual(
             Value(datetime.time(9, 8, 7)).as_mql(None, None),
-            {"$literal": datetime.datetime(1, 1, 1, 9, 8, 7)},
+            datetime.datetime(1, 1, 1, 9, 8, 7),
         )
 
     def test_timedelta(self):
-        self.assertEqual(
-            Value(datetime.timedelta(3600)).as_mql(None, None), {"$literal": 311040000000.0}
-        )
+        self.assertEqual(Value(datetime.timedelta(3600)).as_mql(None, None), 311040000000.0)
 
     def test_int(self):
         self.assertEqual(Value(1).as_mql(None, None), {"$literal": 1})
 
     def test_str(self):
-        self.assertEqual(Value("foo").as_mql(None, None), {"$literal": "foo"})
+        self.assertEqual(Value("foo").as_mql(None, None), "foo")
 
     def test_uuid(self):
         value = uuid.UUID(int=1)
-        self.assertEqual(
-            Value(value).as_mql(None, None), {"$literal": "00000000000000000000000000000001"}
-        )
+        self.assertEqual(Value(value).as_mql(None, None), "00000000000000000000000000000001")