fixup! Corrected OpenAPI schema type for DecimalField

rest_framework/schemas/openapi.py

@@ -6,8 +6,8 @@ from operator import attrgetter
 from urllib.parse import urljoin
 
 from django.core.validators import (
-    EmailValidator, MaxLengthValidator, MaxValueValidator, MinLengthValidator,
+    DecimalValidator, EmailValidator, MaxLengthValidator, MaxValueValidator,
-    MinValueValidator, RegexValidator, URLValidator
+    MinLengthValidator, MinValueValidator, RegexValidator, URLValidator
 )
 from django.db import models
 from django.utils.encoding import force_str
@@ -15,6 +15,7 @@ from django.utils.encoding import force_str
 from rest_framework import exceptions, renderers, serializers
 from rest_framework.compat import uritemplate
 from rest_framework.fields import _UnvalidatedField, empty
+from rest_framework.settings import api_settings
 
 from .generators import BaseSchemaGenerator
 from .inspectors import ViewInspector
@@ -329,10 +330,10 @@ class AutoSchema(ViewInspector):
             type = 'boolean'
         elif all(isinstance(choice, int) for choice in choices):
             type = 'integer'
-        elif all(isinstance(choice, (int, float)) for choice in choices):  # `number` includes `integer`
+        elif all(isinstance(choice, (int, float, Decimal)) for choice in choices):  # `number` includes `integer`
             # Ref: https://tools.ietf.org/html/draft-wright-json-schema-validation-00#section-5.21
             type = 'number'
-        elif all(isinstance(choice, (str, Decimal)) for choice in choices):
+        elif all(isinstance(choice, str) for choice in choices):
             type = 'string'
         else:
             type = None
@@ -443,14 +444,26 @@ class AutoSchema(ViewInspector):
             return content
 
         if isinstance(field, serializers.DecimalField):
-            return {
+            if field.coerce_to_string:
-                'type': 'string',
+                return {
-                'format': 'decimal'
+                    'type': 'string',
-            }
+                    'format': 'decimal',
+                }
+            else:
+                content = {
+                    'type': 'number'
+                }
+                if field.decimal_places:
+                    content['multipleOf'] = float('.' + (field.decimal_places - 1) * '0' + '1')
+                if field.max_whole_digits:
+                    content['maximum'] = int(field.max_whole_digits * '9') + 1
+                    content['minimum'] = -content['maximum']
+                self._map_min_max(field, content)
+                return content
 
         if isinstance(field, serializers.FloatField):
             content = {
-                'type': 'number'
+                'type': 'number',
             }
             self._map_min_max(field, content)
             return content
@@ -549,6 +562,16 @@ class AutoSchema(ViewInspector):
                 schema['maximum'] = v.limit_value
             elif isinstance(v, MinValueValidator):
                 schema['minimum'] = v.limit_value
+            elif isinstance(v, DecimalValidator) and \
+                    not getattr(field, 'coerce_to_string', api_settings.COERCE_DECIMAL_TO_STRING):
+                if v.decimal_places:
+                    schema['multipleOf'] = float('.' + (v.decimal_places - 1) * '0' + '1')
+                if v.max_digits:
+                    digits = v.max_digits
+                    if v.decimal_places is not None and v.decimal_places > 0:
+                        digits -= v.decimal_places
+                    schema['maximum'] = int(digits * '9') + 1
+                    schema['minimum'] = -schema['maximum']
 
     def _get_paginator(self):
         pagination_class = getattr(self.view, 'pagination_class', None)

tests/schemas/test_openapi.py

@@ -830,9 +830,16 @@ class TestOperationIntrospection(TestCase):
         assert properties['regex']['pattern'] == r'[ABC]12{3}'
         assert properties['regex']['description'] == 'must have an A, B, or C followed by 1222'
 
-        assert properties['decimal1'] == {'type': 'string', 'format': 'decimal'}
+        assert properties['decimal1']['type'] == 'number'
+        assert properties['decimal1']['multipleOf'] == .01
+        assert properties['decimal1']['maximum'] == 10000
+        assert properties['decimal1']['minimum'] == -10000
 
-        assert properties['decimal2'] == {'type': 'string', 'format': 'decimal'}
+        assert properties['decimal2']['type'] == 'number'
+        assert properties['decimal2']['multipleOf'] == .0001
+
+        assert properties['decimal3'] == {'type': 'string', 'format': 'decimal'}
+        assert properties['decimal4'] == {'type': 'string', 'format': 'decimal'}
 
         assert properties['email']['type'] == 'string'
         assert properties['email']['format'] == 'email'

tests/schemas/views.py

@@ -119,8 +119,11 @@ class ExampleValidatedSerializer(serializers.Serializer):
             MinLengthValidator(limit_value=2),
         )
     )
-    decimal1 = serializers.DecimalField(max_digits=6, decimal_places=2)
+    decimal1 = serializers.DecimalField(max_digits=6, decimal_places=2, coerce_to_string=False)
-    decimal2 = serializers.DecimalField(max_digits=5, decimal_places=0,
+    decimal2 = serializers.DecimalField(max_digits=5, decimal_places=0, coerce_to_string=False,
+                                        validators=(DecimalValidator(max_digits=17, decimal_places=4),))
+    decimal3 = serializers.DecimalField(max_digits=8, decimal_places=2, coerce_to_string=True)
+    decimal4 = serializers.DecimalField(max_digits=8, decimal_places=2, coerce_to_string=True,
                                         validators=(DecimalValidator(max_digits=17, decimal_places=4),))
     email = serializers.EmailField(default='foo@bar.com')
     url = serializers.URLField(default='http://www.example.com', allow_null=True)