From b7dd5851b9380e48598870c277f525c8e5d685f8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Arttu=20Per=C3=A4l=C3=A4?= <arttu@perala.me>
Date: Thu, 13 Jul 2023 18:37:53 +0300
Subject: [PATCH] Exclude callable field defaults from the OpenAPI schema
 (#1167)

* Exclude callable field defaults from the OpenAPI schema

* Organize callable default test in line with project standards
---
 CHANGELOG.md                               |  1 +
 rest_framework_json_api/schemas/openapi.py |  2 +-
 tests/schemas/test_openapi.py              | 11 +++++++++++
 tests/serializers.py                       | 19 +++++++++++++------
 4 files changed, 26 insertions(+), 7 deletions(-)
 create mode 100644 tests/schemas/test_openapi.py

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 82c32eec..efbe93d2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -53,6 +53,7 @@ any parts of the framework not mentioned in the documentation should generally b
 * Fixed "id" field being added to /data/attributes in the OpenAPI schema when it is not rendered there.
 * Fixed `SerializerMethodResourceRelatedField(many=True)` fields being given
   a "reltoone" schema reference instead of "reltomany".
+* Callable field default values are excluded from the OpenAPI schema, as they don't resolve to YAML data types.
 
 ## [6.0.0] - 2022-09-24
 
diff --git a/rest_framework_json_api/schemas/openapi.py b/rest_framework_json_api/schemas/openapi.py
index cc8ae233..52f08da6 100644
--- a/rest_framework_json_api/schemas/openapi.py
+++ b/rest_framework_json_api/schemas/openapi.py
@@ -727,7 +727,7 @@ def map_serializer(self, serializer):
                 schema["writeOnly"] = True
             if field.allow_null:
                 schema["nullable"] = True
-            if field.default and field.default != empty:
+            if field.default and field.default != empty and not callable(field.default):
                 schema["default"] = field.default
             if field.help_text:
                 # Ensure django gettext_lazy is rendered correctly
diff --git a/tests/schemas/test_openapi.py b/tests/schemas/test_openapi.py
new file mode 100644
index 00000000..427f18fc
--- /dev/null
+++ b/tests/schemas/test_openapi.py
@@ -0,0 +1,11 @@
+from rest_framework_json_api.schemas.openapi import AutoSchema
+from tests.serializers import CallableDefaultSerializer
+
+
+class TestAutoSchema:
+    def test_schema_callable_default(self):
+        inspector = AutoSchema()
+        result = inspector.map_serializer(CallableDefaultSerializer())
+        assert result["properties"]["attributes"]["properties"]["field"] == {
+            "type": "string",
+        }
diff --git a/tests/serializers.py b/tests/serializers.py
index 8894a211..e0f7c03b 100644
--- a/tests/serializers.py
+++ b/tests/serializers.py
@@ -1,5 +1,5 @@
+from rest_framework_json_api import serializers
 from rest_framework_json_api.relations import ResourceRelatedField
-from rest_framework_json_api.serializers import ModelSerializer
 from tests.models import (
     BasicModel,
     ForeignKeySource,
@@ -9,13 +9,13 @@
 )
 
 
-class BasicModelSerializer(ModelSerializer):
+class BasicModelSerializer(serializers.ModelSerializer):
     class Meta:
         fields = ("text",)
         model = BasicModel
 
 
-class ForeignKeySourceSerializer(ModelSerializer):
+class ForeignKeySourceSerializer(serializers.ModelSerializer):
     target = ResourceRelatedField(queryset=ForeignKeyTarget.objects)
 
     class Meta:
@@ -23,7 +23,7 @@ class Meta:
         fields = ("target",)
 
 
-class ManyToManySourceSerializer(ModelSerializer):
+class ManyToManySourceSerializer(serializers.ModelSerializer):
     targets = ResourceRelatedField(many=True, queryset=ManyToManyTarget.objects)
 
     class Meta:
@@ -31,14 +31,21 @@ class Meta:
         fields = ("targets",)
 
 
-class ManyToManyTargetSerializer(ModelSerializer):
+class ManyToManyTargetSerializer(serializers.ModelSerializer):
     class Meta:
         model = ManyToManyTarget
 
 
-class ManyToManySourceReadOnlySerializer(ModelSerializer):
+class ManyToManySourceReadOnlySerializer(serializers.ModelSerializer):
     targets = ResourceRelatedField(many=True, read_only=True)
 
     class Meta:
         model = ManyToManySource
         fields = ("targets",)
+
+
+class CallableDefaultSerializer(serializers.Serializer):
+    field = serializers.CharField(default=serializers.CreateOnlyDefault("default"))
+
+    class Meta:
+        fields = ("field",)