[1.10.x] Properly encode model and dataclass default for schema (#4781)

* Properly encode model and dataclass default for schema

* Wrap type annotation in quotes

* Fix compatibility

* Add changes file

* Remove unnecessary import

Co-authored-by: Hasan Ramezani <hasan.r67@gmail.com>

* Add a blank line back

* Reorder conditions

As per suggestion in #4781 (comment).

Co-authored-by: Hasan Ramezani <hasan.r67@gmail.com>

changes/4781-Bobronium.md

@@ -0,0 +1 @@
+Fix `schema` and `schema_json` on models where a model instance is a one of default values.

pydantic/schema.py

@@ -1,6 +1,7 @@
 import re
 import warnings
 from collections import defaultdict
+from dataclasses import is_dataclass
 from datetime import date, datetime, time, timedelta
 from decimal import Decimal
 from enum import Enum
@@ -931,16 +932,21 @@ def multitypes_literal_field_for_schema(values: Tuple[Any, ...], field: ModelFie
 
 
 def encode_default(dft: Any) -> Any:
-    if isinstance(dft, Enum):
+    from .main import BaseModel
+
+    if isinstance(dft, BaseModel) or is_dataclass(dft):
+        dft = cast('dict[str, Any]', pydantic_encoder(dft))
+
+    if isinstance(dft, dict):
+        return {encode_default(k): encode_default(v) for k, v in dft.items()}
+    elif isinstance(dft, Enum):
         return dft.value
     elif isinstance(dft, (int, float, str)):
         return dft
     elif isinstance(dft, (list, tuple)):
         t = dft.__class__
         seq_args = (encode_default(v) for v in dft)
         return t(*seq_args) if is_namedtuple(t) else t(seq_args)
-    elif isinstance(dft, dict):
-        return {encode_default(k): encode_default(v) for k, v in dft.items()}
     elif dft is None:
         return None
     else:

tests/test_schema.py

@@ -1512,6 +1512,38 @@ class UserModel(BaseModel):
     }
 
 
+def test_model_default():
+    """Make sure inner model types are encoded properly"""
+
+    class Inner(BaseModel):
+        a: Dict[Path, str] = {Path(): ''}
+
+    class Outer(BaseModel):
+        inner: Inner = Inner()
+
+    assert Outer.schema() == {
+        'definitions': {
+            'Inner': {
+                'properties': {
+                    'a': {
+                        'additionalProperties': {'type': 'string'},
+                        'default': {'.': ''},
+                        'title': 'A',
+                        'type': 'object',
+                    }
+                },
+                'title': 'Inner',
+                'type': 'object',
+            }
+        },
+        'properties': {
+            'inner': {'allOf': [{'$ref': '#/definitions/Inner'}], 'default': {'a': {'.': ''}}, 'title': 'Inner'}
+        },
+        'title': 'Outer',
+        'type': 'object',
+    }
+
+
 @pytest.mark.parametrize(
     'kwargs,type_,expected_extra',
     [