Prevent JSONField from adding CAST(... AS JSON) for str/int/float (#621)

Fixes #480.

Author: arnau126

HISTORY.rst

@@ -8,6 +8,8 @@ Pending
 
 * Prevent ``collections.abc.Sequence`` warning.
 * Drop Django 1.11 support. Only Django 2.0+ is supported now.
+* Prevent ``JSONField`` from adding ``CAST(... AS JSON)`` to queries against
+  ``str``, ``int``, and ``float`` types.
 
 3.3.0 (2019-12-10)
 ------------------

src/django_mysql/models/lookups.py

@@ -2,7 +2,7 @@
 from collections.abc import Sequence
 
 import django
-from django.db.models import CharField, Lookup, Transform
+from django.db.models import CharField, Lookup, Transform, Value
 from django.db.models.lookups import (
     BuiltinLookup,
     Exact,
@@ -53,15 +53,21 @@ class JSONLookupMixin:
         def get_prep_lookup(self):
             value = self.rhs
             if not hasattr(value, "resolve_expression") and value is not None:
-                return JSONValue(value)
+                if isinstance(value, (str, int, float)) and not isinstance(value, bool):
+                    return Value(value)
+                else:
+                    return JSONValue(value)
             return super().get_prep_lookup()
 
     else:
 
         def get_prep_lookup(self):
             value = self.rhs
             if not hasattr(value, "_prepare") and value is not None:
-                return JSONValue(value)
+                if isinstance(value, (str, int, float)) and not isinstance(value, bool):
+                    return Value(value)
+                else:
+                    return JSONValue(value)
             return super().get_prep_lookup()
 
 

tests/testapp/models.py

@@ -280,6 +280,8 @@ class JSONModel(Model):
     ) and connection._nodb_connection.mysql_version >= (5, 7):
         attrs = JSONField(null=True)
 
+    name = CharField(max_length=3)
+
     def __unicode__(self):
         return str(json.dumps(self.attrs))
 

tests/testapp/test_jsonfield.py

@@ -132,27 +132,38 @@ def setUp(self):
         super().setUp()
         JSONModel.objects.bulk_create(
             [
-                JSONModel(attrs={"a": "b"}),
-                JSONModel(attrs=1337),
+                JSONModel(attrs={"a": "b"}, name="b"),
+                JSONModel(attrs=1337, name="x"),
                 JSONModel(attrs=["an", "array"]),
                 JSONModel(attrs=None),
-                JSONModel(attrs="foo"),
+                JSONModel(attrs="foo", name="foo"),
+                JSONModel(attrs=True),
+                JSONModel(attrs=False),
+                JSONModel(attrs=0.5),
             ]
         )
         self.objs = list(JSONModel.objects.all().order_by("id"))
 
     def test_equal(self):
         assert list(JSONModel.objects.filter(attrs={"a": "b"})) == [self.objs[0]]
 
-    def test_equal_value(self):
+    def test_equal_int(self):
         assert list(JSONModel.objects.filter(attrs=1337)) == [self.objs[1]]
 
+    def test_equal_float(self):
+        assert list(JSONModel.objects.filter(attrs=0.5)) == [self.objs[7]]
+        assert list(JSONModel.objects.filter(attrs=0.501)) == []
+
     def test_equal_string(self):
         assert list(JSONModel.objects.filter(attrs="foo")) == [self.objs[4]]
 
     def test_equal_array(self):
         assert list(JSONModel.objects.filter(attrs=["an", "array"])) == [self.objs[2]]
 
+    def test_equal_bool(self):
+        assert list(JSONModel.objects.filter(attrs=True)) == [self.objs[5]]
+        assert list(JSONModel.objects.filter(attrs=False)) == [self.objs[6]]
+
     def test_equal_no_match(self):
         assert list(JSONModel.objects.filter(attrs={"c": "z"})) == []
 
@@ -162,7 +173,12 @@ def test_equal_F_attrs(self):
             self.objs[1],
             self.objs[2],
             self.objs[4],
+            self.objs[5],
+            self.objs[6],
+            self.objs[7],
         ]
+        assert list(JSONModel.objects.filter(attrs=F("name"))) == [self.objs[4]]
+        assert list(JSONModel.objects.filter(attrs__a=F("name"))) == [self.objs[0]]
 
     def test_isnull_True(self):
         assert list(JSONModel.objects.filter(attrs__isnull=True)) == [self.objs[3]]
@@ -173,6 +189,9 @@ def test_isnull_False(self):
             self.objs[1],
             self.objs[2],
             self.objs[4],
+            self.objs[5],
+            self.objs[6],
+            self.objs[7],
         ]
 
     def test_range_broken(self):
@@ -507,7 +526,8 @@ class TestSerialization(JSONFieldTestCase):
     test_data = """[
         {
             "fields": {
-                "attrs": {"a": "b", "c": null}
+                "attrs": {"a": "b", "c": null},
+                "name": ""
             },
             "model": "testapp.jsonmodel",
             "pk": null