put back old behaviour and add to_dict

docs/examples/exporting_models_json_forward_ref.py

@@ -31,4 +31,4 @@ class Config:
         User(name='John', address=Address(city='London', country='UK')),
     ],
 )
-print(wolfgang.json())
+print(wolfgang.json(to_dict=False))

docs/usage/exporting_models.md

@@ -109,6 +109,8 @@ _(This script is complete, it should run "as is")_
 
 ### Serialising self-reference or other models
 
+By default, models are serialised as dictionaries.
+If you want to serialise them differently, you can add `to_dict=False` and add the classes of the model in `json_encoders`.
 In case of forward references, you can use a string with the class name instead of the class itself
 ```py
 {!.tmp_examples/exporting_models_json_forward_ref.py!}

tests/test_json.py

@@ -281,7 +281,7 @@ class Config:
     assert m.json() == '{\n  "a": 1,\n  "b": "foo"\n}'
 
 
-def test_json_nested_encode():
+def test_json_nested_encode_models():
     class Phone(BaseModel):
         manufacturer: str
         number: int
@@ -314,11 +314,15 @@ class Config:
 
     timon.friend = pumbaa
 
-    assert iphone.json() == '{"manufacturer": "Apple", "number": 18002752273}'
+    assert iphone.json(to_dict=False) == '{"manufacturer": "Apple", "number": 18002752273}'
     assert (
-        pumbaa.json() == '{"name": "Pumbaa", "SSN": 234, "birthday": 737424000.0, "phone": 18007267864, "friend": null}'
+        pumbaa.json(to_dict=False)
+        == '{"name": "Pumbaa", "SSN": 234, "birthday": 737424000.0, "phone": 18007267864, "friend": null}'
+    )
+    assert (
+        timon.json(to_dict=False)
+        == '{"name": "Timon", "SSN": 123, "birthday": 738892800.0, "phone": 18002752273, "friend": 234}'
     )
-    assert timon.json() == '{"name": "Timon", "SSN": 123, "birthday": 738892800.0, "phone": 18002752273, "friend": 234}'
 
 
 def test_custom_encode_fallback_basemodel():
@@ -357,3 +361,11 @@ class Config:
 
     with pytest.raises(TypeError, match='not serialisable'):
         Foo(x=MyExoticType()).json(encoder=custom_encoder)
+
+
+def test_recursive():
+    class Model(BaseModel):
+        value: Optional[str]
+        nested: Optional[BaseModel]
+
+    assert Model(value=None, nested=Model(value=None)).json(exclude_none=True) == '{"nested": {}}'