Revert "Add nested json encoding (#3941)" (#4367)

This reverts commit b42fae0.

docs/usage/exporting_models.md

@@ -118,20 +118,6 @@ In case of forward references, you can use a string with the class name instead
 ```
 _(This script is complete, it should run "as is")_
 
-### Nested serialisation of other models
-
-By default, models that contain other models are serialised using the `json_encoders` functions of the
-parent or container class.
-However, you may want to nest classes in a modular fashion, including their `json_encoders`.
-In this case, call `json(use_nested_encoders=True)`.
-`use_nested_encoders` has no effect when `models_as_dict=False`, as the classes of the models
-are expected to be defined in the top-level `json_encoders`.
-
-```py
-{!.tmp_examples/exporting_models_json_nested_encoders.py!}
-```
-_(This script is complete, it should run "as is")_
-
 ### Serialising subclasses
 
 !!! note

pydantic/main.py

@@ -427,7 +427,6 @@ def dict(
         exclude_unset: bool = False,
         exclude_defaults: bool = False,
         exclude_none: bool = False,
-        encode_as_json: bool = False,
     ) -> 'DictStrAny':
         """
         Generate a dictionary representation of the model, optionally specifying which fields to include or exclude.
@@ -449,7 +448,6 @@ def dict(
                 exclude_unset=exclude_unset,
                 exclude_defaults=exclude_defaults,
                 exclude_none=exclude_none,
-                encode_as_json=encode_as_json,
             )
         )
 
@@ -465,7 +463,6 @@ def json(
         exclude_none: bool = False,
         encoder: Optional[Callable[[Any], Any]] = None,
         models_as_dict: bool = True,
-        use_nested_encoders: bool = False,
         **dumps_kwargs: Any,
     ) -> str:
         """
@@ -493,7 +490,6 @@ def json(
                 exclude_unset=exclude_unset,
                 exclude_defaults=exclude_defaults,
                 exclude_none=exclude_none,
-                encode_as_json=use_nested_encoders,
             )
         )
         if self.__custom_root_type__:
@@ -714,7 +710,6 @@ def _get_value(
         exclude_unset: bool,
         exclude_defaults: bool,
         exclude_none: bool,
-        encode_as_json: bool = False,
     ) -> Any:
 
         if isinstance(v, BaseModel):
@@ -726,7 +721,6 @@ def _get_value(
                     include=include,
                     exclude=exclude,
                     exclude_none=exclude_none,
-                    encode_as_json=encode_as_json,
                 )
                 if ROOT_KEY in v_dict:
                     return v_dict[ROOT_KEY]
@@ -776,9 +770,6 @@ def _get_value(
         elif isinstance(v, Enum) and getattr(cls.Config, 'use_enum_values', False):
             return v.value
 
-        elif encode_as_json:
-            return cls.__json_encoder__(v)
-
         else:
             return v
 
@@ -812,7 +803,6 @@ def _iter(
         exclude_unset: bool = False,
         exclude_defaults: bool = False,
         exclude_none: bool = False,
-        encode_as_json: bool = False,
     ) -> 'TupleGenerator':
 
         # Merge field set excludes with explicit exclude parameter with explicit overriding field set options.
@@ -858,7 +848,6 @@ def _iter(
                     exclude_unset=exclude_unset,
                     exclude_defaults=exclude_defaults,
                     exclude_none=exclude_none,
-                    encode_as_json=encode_as_json,
                 )
             yield dict_key, v
 

tests/test_json.py

@@ -372,81 +372,3 @@ class Model(BaseModel):
         nested: Optional[BaseModel]
 
     assert Model(value=None, nested=Model(value=None)).json(exclude_none=True) == '{"nested": {}}'
-
-
-class WithCustomEncoders(BaseModel):
-    dt: datetime.datetime
-    diff: datetime.timedelta
-
-    class Config:
-        json_encoders = {
-            datetime.datetime: lambda v: v.timestamp(),
-            datetime.timedelta: timedelta_isoformat,
-        }
-
-
-ides_of_march = datetime.datetime(44, 3, 15, tzinfo=datetime.timezone.utc)
-
-child = WithCustomEncoders(
-    dt=datetime.datetime(2032, 6, 1, tzinfo=datetime.timezone.utc),
-    diff=datetime.timedelta(hours=100),
-)
-
-
-def test_inner_custom_encoding():
-    assert child.json() == r'{"dt": 1969660800.0, "diff": "P4DT4H0M0.000000S"}'
-
-
-def test_encoding_in_parent_with_variable_encoders():
-    class ParentWithVariableEncoders(BaseModel):
-        dt: datetime.datetime
-        child: WithCustomEncoders
-
-        class Config:
-            json_encoders = {
-                datetime.datetime: lambda v: v.year,
-                datetime.timedelta: lambda v: v.total_seconds(),
-            }
-
-    parent = ParentWithVariableEncoders(child=child, dt=ides_of_march)
-
-    default = r'{"dt": 44, "child": {"dt": 2032, "diff": 360000.0}}'
-    assert parent.json() == default
-    # turning off models_as_dict defaults to top-level
-    assert parent.json(models_as_dict=False, use_nested_encoders=False) == default
-    assert parent.json(models_as_dict=False, use_nested_encoders=True) == default
-
-    custom = (
-        r'{"dt": 44, '  # parent.dt still uses the year to encode
-        # child uses child.json_encoders to encode
-        r'"child": {"dt": 1969660800.0, "diff": "P4DT4H0M0.000000S"}}'
-    )
-    assert parent.json(use_nested_encoders=True) == custom
-
-
-def test_encoding_in_parent_with_class_encoders():
-    class ParentWithClassEncoders(BaseModel):
-        dt: datetime.datetime
-        child: WithCustomEncoders
-
-        class Config:
-            json_encoders = {
-                datetime.datetime: lambda v: v.timestamp(),
-                WithCustomEncoders: lambda v: {'dt': v.dt.year},
-            }
-
-    parent = ParentWithClassEncoders(child=child, dt=ides_of_march)
-
-    # when models_as_dict=True, the `WithCustomEncoders` encoder is ignored
-    default = r'{"dt": -60772291200.0, "child": {"dt": 1969660800.0, "diff": 360000.0}}'
-    assert parent.json() == default
-
-    custom_child = r'{"dt": -60772291200.0, "child": {"dt": 1969660800.0, "diff": "P4DT4H0M0.000000S"}}'
-    assert parent.json(use_nested_encoders=True) == custom_child
-
-    # when models_as_dict=False, the parent `WithCustomEncoders` is used
-    # regardless of whatever json_encoders are in WithCustomEncoders.Config
-
-    custom_parent = r'{"dt": -60772291200.0, "child": {"dt": 2032}}'
-    assert parent.json(models_as_dict=False, use_nested_encoders=False) == custom_parent
-    assert parent.json(models_as_dict=False, use_nested_encoders=True) == custom_parent