feat: enforce Decimal type in min_value and max_value arguments of DecimalField

Author: IsmaelJS

rest_framework/fields.py

@@ -990,6 +990,11 @@ def __init__(self, max_digits, decimal_places, coerce_to_string=None, max_value=
         self.max_value = max_value
         self.min_value = min_value
 
+        if self.max_value is not None and not isinstance(self.max_value, decimal.Decimal):
+            raise ValueError("Invalid type of max_value argument. It must be decimal.")
+        if self.min_value is not None and not isinstance(self.min_value, decimal.Decimal):
+            raise ValueError("Invalid type of min_value argument. It must be decimal.")
+
         if self.max_digits is not None and self.decimal_places is not None:
             self.max_whole_digits = self.max_digits - self.decimal_places
         else:

tests/importable/__init__.py

@@ -2,6 +2,7 @@
 This test "app" exists to ensure that parts of Django REST Framework can be
 imported/invoked before Django itself has been fully initialized.
 """
+from decimal import Decimal
 
 from rest_framework import compat, serializers  # noqa
 
@@ -11,6 +12,6 @@ class ExampleSerializer(serializers.Serializer):
     charfield = serializers.CharField(min_length=1, max_length=2)
     integerfield = serializers.IntegerField(min_value=1, max_value=2)
     floatfield = serializers.FloatField(min_value=1, max_value=2)
-    decimalfield = serializers.DecimalField(max_digits=10, decimal_places=1, min_value=1, max_value=2)
+    decimalfield = serializers.DecimalField(max_digits=10, decimal_places=1, min_value=Decimal('1'), max_value=Decimal('2'))
     durationfield = serializers.DurationField(min_value=1, max_value=2)
     listfield = serializers.ListField(min_length=1, max_length=2)

tests/test_fields.py

@@ -1203,17 +1203,17 @@ class TestMinMaxDecimalField(FieldValues):
     Valid and invalid values for `DecimalField` with min and max limits.
     """
     valid_inputs = {
-        '10.0': Decimal('10.0'),
-        '20.0': Decimal('20.0'),
+        '10.1': Decimal('10.1'),
+        '20.1': Decimal('20.1'),
     }
     invalid_inputs = {
-        '9.9': ['Ensure this value is greater than or equal to 10.'],
-        '20.1': ['Ensure this value is less than or equal to 20.'],
+        '9.9': ['Ensure this value is greater than or equal to 10.1.'],
+        '20.2': ['Ensure this value is less than or equal to 20.1.'],
     }
     outputs = {}
     field = serializers.DecimalField(
         max_digits=3, decimal_places=1,
-        min_value=10, max_value=20
+        min_value=Decimal('10.1'), max_value=Decimal('20.1')
     )
 
 
@@ -1238,12 +1238,12 @@ class TestAllowEmptyStrDecimalFieldWithValidators(FieldValues):
     outputs = {
         None: '',
     }
-    field = serializers.DecimalField(max_digits=3, decimal_places=1, allow_null=True, min_value=0, max_value=10)
+    field = serializers.DecimalField(max_digits=3, decimal_places=1, allow_null=True, min_value=Decimal('0'), max_value=Decimal('10'))
 
 
 class TestNoMaxDigitsDecimalField(FieldValues):
     field = serializers.DecimalField(
-        max_value=100, min_value=0,
+        max_value=Decimal('100'), min_value=Decimal('0'),
         decimal_places=2, max_digits=None
     )
     valid_inputs = {

tests/test_model_serializer.py

@@ -1095,7 +1095,7 @@ class DecimalFieldModel(models.Model):
     decimal_field = models.DecimalField(
         max_digits=3,
         decimal_places=1,
-        validators=[MinValueValidator(1), MaxValueValidator(3)]
+        validators=[MinValueValidator(decimal.Decimal('1')), MaxValueValidator(decimal.Decimal('3'))]
     )