handle Decimals for YAML #316

drf_spectacular/renderers.py

@@ -1,3 +1,5 @@
+from decimal import Decimal
+
 import yaml
 from rest_framework.exceptions import ErrorDetail
 from rest_framework.renderers import BaseRenderer, JSONRenderer
@@ -23,6 +25,15 @@ def multiline_str_representer(dumper, data):
             return scalar
         Dumper.add_representer(str, multiline_str_representer)
 
+        def decimal_representer(dumper, data):
+            # prevent emitting "!! float" tags on fractionless decimals
+            value = str(data)
+            if '.' in value:
+                return dumper.represent_scalar('tag:yaml.org,2002:float', value)
+            else:
+                return dumper.represent_scalar('tag:yaml.org,2002:int', value)
+        Dumper.add_representer(Decimal, decimal_representer)
+
         return yaml.dump(
             data,
             default_flow_style=False,

drf_spectacular/validation/__init__.py

@@ -19,6 +19,7 @@ def validate_schema(api_schema):
         openapi3_schema_spec = json.load(fh)
 
     # coerce any remnants of objects to basic types
-    api_schema = json.loads(json.dumps(api_schema))
+    from drf_spectacular.renderers import OpenApiJsonRenderer
+    api_schema = json.loads(OpenApiJsonRenderer().render(api_schema))
 
     jsonschema.validate(instance=api_schema, schema=openapi3_schema_spec)

tests/test_regressions.py

@@ -1,5 +1,6 @@
 import typing
 import uuid
+from decimal import Decimal
 from unittest import mock
 
 import pytest
@@ -19,6 +20,7 @@
 from drf_spectacular.generators import SchemaGenerator
 from drf_spectacular.hooks import preprocess_exclude_path_format
 from drf_spectacular.openapi import AutoSchema
+from drf_spectacular.renderers import OpenApiYamlRenderer
 from drf_spectacular.types import OpenApiTypes
 from drf_spectacular.utils import (
     OpenApiParameter, extend_schema, extend_schema_field, extend_schema_serializer,
@@ -1250,6 +1252,37 @@ def view_func(request, format=None):
     assert field['minimum'] == -100
 
 
+def test_serialization_with_decimal_values(no_warnings):
+    class XSerializer(serializers.Serializer):
+        field = serializers.DecimalField(
+            decimal_places=2,
+            min_value=Decimal('1'),
+            max_value=Decimal('100.00'),
+            max_digits=5,
+            coerce_to_string=False,
+        )
+        field_coerced = serializers.DecimalField(
+            decimal_places=2,
+            min_value=Decimal('1'),
+            max_value=Decimal('100.00'),
+            max_digits=5,
+            coerce_to_string=True,
+        )
+
+    @extend_schema(responses=XSerializer)
+    @api_view(['GET'])
+    def view_func(request):
+        pass  # pragma: no cover
+
+    schema = generate_schema('/x/', view_function=view_func)
+    field = schema['components']['schemas']['X']['properties']['field']
+    assert field['minimum'] and field['maximum']
+
+    schema_yml = OpenApiYamlRenderer().render(schema, renderer_context={})
+    assert b'maximum: 100.00\n' in schema_yml
+    assert b'minimum: 1\n' in schema_yml
+
+
 def test_non_supported_http_verbs(no_warnings):
     HTTP_METHODS = [
         'GET',