clean Model docstrings in JSON Schema

docs/usage/json_schema.md

@@ -95,7 +95,7 @@ print(json.dumps(MainModel.model_json_schema(), indent=2))
       "type": "string"
     }
   },
-  "description": "\n    This is the description of the main model\n    ",
+  "description": "This is the description of the main model",
   "properties": {
     "foo_bar": {
       "$ref": "#/$defs/FooBar"

pydantic/_internal/_generate_schema.py

@@ -219,7 +219,7 @@ def modify_model_json_schema(
         original_schema['title'] = cls.__name__
     docstring = cls.__doc__
     if docstring and 'description' not in original_schema:
-        original_schema['description'] = docstring
+        original_schema['description'] = inspect.cleandoc(docstring)
     return json_schema
 
 

tests/test_json_schema.py

@@ -1695,6 +1695,25 @@ class B(A):
     assert B.model_json_schema() == {'title': 'B', 'type': 'object', 'properties': {}}
 
 
+@pytest.mark.parametrize(
+    'docstring,description',
+    [
+        ('foobar', 'foobar'),
+        ('\n     foobar\n    ', 'foobar'),
+        ('foobar\n    ', 'foobar\n    '),
+        ('foo\n    bar\n    ', 'foo\nbar'),
+        ('\n    foo\n    bar\n    ', 'foo\nbar'),
+    ],
+)
+def test_docstring(docstring, description):
+    class A(BaseModel):
+        x: int
+
+    A.__doc__ = docstring
+
+    assert A.model_json_schema()['description'] == description
+
+
 @pytest.mark.parametrize(
     'kwargs,type_,expected_extra',
     [