Fixed #18389 -- Fixed the way contribute_to_class is called

Now this method is only called only if the object is an instance.
This allows to have field classes as model class attributes.

1 files changed, 11 insertions, 1 deletions

diff --git a/tests/model_fields/models.py b/tests/model_fields/models.py
index 8a6e9c83b1..0222f9a3df 100644
--- a/tests/model_fields/models.py
+++ b/tests/model_fields/models.py
@@ -145,12 +145,22 @@ class VerboseNameField(models.Model):
     field22 = models.URLField("verbose field22")
 
 
-# This model isn't used in any test, just here to ensure it validates successfully.
+###############################################################################
+# These models aren't used in any test, just here to ensure they validate
+# successfully.
+
 # See ticket #16570.
 class DecimalLessThanOne(models.Model):
     d = models.DecimalField(max_digits=3, decimal_places=3)
 
 
+# See ticket #18389.
+class FieldClassAttributeModel(models.Model):
+    field_class = models.CharField
+
+###############################################################################
+
+
 class DataModel(models.Model):
     short_data = models.BinaryField(max_length=10, default=b'\x08')
     data = models.BinaryField()