add enum key/value list to description string #337 #403 #105 #563

Thanks to @valentijnscholten for the first attempt in #403

drf_spectacular/contrib/django_filters.py

@@ -3,9 +3,10 @@
 from drf_spectacular.drainage import add_trace_message, get_override, has_override, warn
 from drf_spectacular.extensions import OpenApiFilterExtension
 from drf_spectacular.plumbing import (
-    build_array_type, build_basic_type, build_parameter_type, follow_field_source, get_manager,
-    get_type_hints, get_view_model, is_basic_type,
+    build_array_type, build_basic_type, build_choice_description_list, build_parameter_type,
+    follow_field_source, get_manager, get_type_hints, get_view_model, is_basic_type,
 )
+from drf_spectacular.settings import spectacular_settings
 from drf_spectacular.types import OpenApiTypes
 from drf_spectacular.utils import OpenApiParameter
 
@@ -154,10 +155,8 @@ def resolve_filter_field(self, auto_schema, model, filterset_class, field_name,
             enum = filter_choices
 
         description = schema.pop('description', None)
-        if filter_field.extra.get('help_text', None):
-            description = filter_field.extra['help_text']
-        elif filter_field.label is not None:
-            description = filter_field.label
+        if not schema_from_override:
+            description = self._get_field_description(filter_field, description)
 
         # parameter style variations based on filter base class
         if isinstance(filter_field, filters.BaseCSVFilter):
@@ -248,6 +247,35 @@ def _get_schema_from_model_field(self, auto_schema, filter_field, model):
             model_field = qs.query.annotations[filter_field.field_name].field
         return auto_schema._map_model_field(model_field, direction=None)
 
+    def _get_field_description(self, filter_field, description):
+        # Try to improve description beyond auto-generated model description
+        if filter_field.extra.get('help_text', None):
+            description = filter_field.extra['help_text']
+        elif filter_field.label is not None:
+            description = filter_field.label
+
+        choices = filter_field.extra.get('choices')
+        if choices and callable(choices):
+            # remove auto-generated enum list, since choices come from a callable
+            if '\n\n*' in (description or ''):
+                description, _, _ = description.partition('\n\n*')
+            return description
+
+        choice_description = ''
+        if spectacular_settings.ENUM_GENERATE_CHOICE_DESCRIPTION and choices and not callable(choices):
+            choice_description = build_choice_description_list(choices)
+
+        if not choices:
+            return description
+
+        if description:
+            # replace or append model choice description
+            if '\n\n*' in description:
+                description, _, _ = description.partition('\n\n*')
+            return description + '\n\n' + choice_description
+        else:
+            return choice_description
+
     @classmethod
     def _is_gis(cls, field):
         if not getattr(cls, '_has_gis', True):

drf_spectacular/hooks.py

@@ -119,6 +119,13 @@ def create_enum_component(name, schema):
             enum_schema = {k: v for k, v in prop_schema.items() if k in ['type', 'enum']}
             prop_schema = {k: v for k, v in prop_schema.items() if k not in ['type', 'enum']}
 
+            # separate actual description from name-value tuples
+            if prop_schema.get('description', '').startswith('*'):
+                enum_schema['description'] = prop_schema.pop('description')
+            elif '\n\n*' in prop_schema.get('description', ''):
+                _, _, post = prop_schema['description'].partition('\n\n*')
+                enum_schema['description'] = '*' + post
+
             components = [
                 create_enum_component(enum_name, schema=enum_schema)
             ]

drf_spectacular/openapi.py

@@ -723,7 +723,10 @@ def _map_serializer_field(self, field, direction, bypass_extensions=False):
             return append_meta(build_array_type(build_choice_field(field)), meta)
 
         if isinstance(field, serializers.ChoiceField):
-            return append_meta(build_choice_field(field), meta)
+            schema = build_choice_field(field)
+            if 'description' in meta:
+                meta['description'] = meta['description'] + '\n\n' + schema.pop('description')
+            return append_meta(schema, meta)
 
         if isinstance(field, serializers.ListField):
             if isinstance(field.child, _UnvalidatedField):

drf_spectacular/plumbing.py

@@ -423,9 +423,17 @@ def build_choice_field(field):
     # Ref: https://tools.ietf.org/html/draft-wright-json-schema-validation-00#section-5.21
     if type:
         schema['type'] = type
+
+    if spectacular_settings.ENUM_GENERATE_CHOICE_DESCRIPTION:
+        schema['description'] = build_choice_description_list(field.choices.items())
+
     return schema
 
 
+def build_choice_description_list(choices) -> str:
+    return '\n'.join(f'* `{value}` - {label}' for value, label in choices)
+
+
 def build_bearer_security_scheme_object(header_name, token_prefix, bearer_format=None):
     """ Either build a bearer scheme or a fallback due to OpenAPI 3.0.3 limitations """
     # normalize Django header quirks

drf_spectacular/settings.py

@@ -112,6 +112,8 @@
     'ENUM_NAME_OVERRIDES': {},
     # Adds "blank" and "null" enum choices where appropriate. disable on client generation issues
     'ENUM_ADD_EXPLICIT_BLANK_NULL_CHOICE': True,
+    # Add/Append a list of (``choice value`` - choice name) to the enum description string.
+    'ENUM_GENERATE_CHOICE_DESCRIPTION': True,
 
     # function that returns a list of all classes that should be excluded from doc string extraction
     'GET_LIB_DOC_EXCLUDES': 'drf_spectacular.plumbing.get_lib_doc_excludes',

tests/contrib/test_django_filters.yml

@@ -24,7 +24,11 @@ paths:
           enum:
           - A
           - B
-        description: some category description
+        description: |-
+          some category description
+
+          * `A` - aaa
+          * `B` - b
       - in: query
         name: choice_field_enum_override
         schema:
@@ -101,7 +105,11 @@ paths:
             enum:
             - A
             - B
-        description: some category description
+        description: |-
+          some category description
+
+          * `A` - aaa
+          * `B` - b
         explode: true
         style: form
       - in: query
@@ -119,7 +127,11 @@ paths:
           enum:
           - A
           - B
-        description: some category description
+        description: |-
+          some category description
+
+          * `A` - aaa
+          * `B` - b
       - in: query
         name: number_id
         schema:
@@ -140,7 +152,13 @@ paths:
             - -price
             - in_stock
             - price
-        description: Ordering
+        description: |-
+          Ordering
+
+          * `price` - Price
+          * `-price` - Price (descending)
+          * `in_stock` - in stock
+          * `-in_stock` - in stock (descending)
         explode: false
         style: form
       - in: query
@@ -191,6 +209,7 @@ paths:
           type: integer
           enum:
           - 1
+        description: '* `1` - one'
       - in: query
         name: untyped_multiple_choice_field_method_with_explicit_choices
         schema:
@@ -199,6 +218,7 @@ paths:
             type: integer
             enum:
             - 1
+        description: '* `1` - one'
         explode: true
         style: form
       tags:
@@ -246,6 +266,9 @@ components:
       - A
       - B
       type: string
+      description: |-
+        * `A` - aaa
+        * `B` - b
     Product:
       type: object
       properties:
@@ -255,7 +278,11 @@ components:
         category:
           allOf:
           - $ref: '#/components/schemas/CategoryEnum'
-          description: some category description
+          description: |-
+            some category description
+
+            * `A` - aaa
+            * `B` - b
         in_stock:
           type: boolean
         price:

tests/test_basic.yml

@@ -212,6 +212,9 @@ components:
       - POP
       - ROCK
       type: string
+      description: |-
+        * `POP` - Pop
+        * `ROCK` - Rock
     PatchedAlbum:
       type: object
       properties:

tests/test_extend_schema.yml

@@ -269,6 +269,10 @@ paths:
             - b
             - c
             type: string
+            description: |-
+              * `a` - a
+              * `b` - b
+              * `c` - c
           default:
           - a
       - in: query
@@ -367,6 +371,9 @@ components:
       - a
       - b
       type: string
+      description: |-
+        * `a` - a
+        * `b` - b
     GammaEpsilon:
       type: object
       properties:
@@ -394,6 +401,10 @@ components:
       - b
       - c
       type: string
+      description: |-
+        * `a` - a
+        * `b` - b
+        * `c` - c
     Query:
       type: object
       properties:

tests/test_postprocessing.yml

@@ -70,6 +70,11 @@ components:
       - ru
       - cn
       type: string
+      description: |-
+        * `en` - en
+        * `es` - es
+        * `ru` - ru
+        * `cn` - cn
     NullEnum:
       enum:
       - null
@@ -79,6 +84,10 @@ components:
       - 0
       - -1
       type: integer
+      description: |-
+        * `1` - Positive
+        * `0` - Neutral
+        * `-1` - Negative
   securitySchemes:
     basicAuth:
       type: http