Fixed #28431 -- Add system check to prevent string as the default val…

…ue for BinaryField.
django · Mar 17, 2019 · f640f41 · f640f41
1 parent 95b7699
commit f640f41
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diff --git a/django/db/models/fields/__init__.py b/django/db/models/fields/__init__.py
@@ -2252,6 +2252,22 @@ def __init__(self, *args, **kwargs):
         if self.max_length is not None:
             self.validators.append(validators.MaxLengthValidator(self.max_length))
 
+    def check(self, **kwargs):
+        errors = super().check(**kwargs)
+        errors.extend(self._check_default_is_not_str(**kwargs))
+        return errors
+
+    def _check_default_is_not_str(self, **kwargs):
+        if self.has_default() and isinstance(self.default, str):
+            return [
+                checks.Error(
+                    "BinaryField 'default' cannot be a string, use bytes content instead.",
+                    obj=self,
+                    id='fields.E170',
+                )
+            ]
+        return []
+
     def deconstruct(self):
         name, path, args, kwargs = super().deconstruct()
         if self.editable:

diff --git a/docs/ref/checks.txt b/docs/ref/checks.txt
@@ -159,6 +159,8 @@ Model fields
 * **fields.W161**: Fixed default value provided.
 * **fields.W162**: ``<database>`` does not support a database index on
   ``<field data type>`` columns.
+* **fields.E170**: ``BinaryField`` ``default`` cannot be a string, use bytes
+  content instead.
 * **fields.E900**: ``IPAddressField`` has been removed except for support in
   historical migrations.
 * **fields.W900**: ``IPAddressField`` has been deprecated. Support for it

diff --git a/tests/invalid_models_tests/test_ordinary_fields.py b/tests/invalid_models_tests/test_ordinary_fields.py
@@ -700,3 +700,32 @@ class Model(models.Model):
                 id='fields.W162',
             )
         ])
+
+
+@isolate_apps('invalid_models_tests')
+class BinaryFieldTests(SimpleTestCase):
+
+    def test_default_value(self):
+        class ModelWithDefaultBinaryValue(models.Model):
+            field = models.BinaryField(default=b'test')
+
+        class ModelWithDefaultNoneValue(models.Model):
+            field = models.BinaryField(default=None)
+
+        for Model in (ModelWithDefaultBinaryValue, ModelWithDefaultNoneValue):
+            with self.subTest(Model=Model):
+                field = Model._meta.get_field('field')
+                self.assertEqual(field.check(), [])
+
+    def test_default_string(self):
+        class Model(models.Model):
+            field = models.BinaryField(default='test')
+
+        field = Model._meta.get_field('field')
+        self.assertEqual(field.check(), [
+            Error(
+                "BinaryField 'default' cannot be a string, use bytes content instead.",
+                obj=field,
+                id='fields.E170',
+            ),
+        ])