# Buggy code
def get_field_info_schema(field: ModelField) -> Tuple[Dict[str, Any], bool]:
    schema_overrides = False

    # If no title is explicitly set, we don't set title in the schema for enums.
    # The behaviour is the same as `BaseModel` reference, where the default title
    # is in the definitions part of the schema.
    schema: Dict[str, Any] = {}
    if field.field_info.title or not lenient_issubclass(field.type_, Enum):
        schema["title"] = field.field_info.title or field.alias.title().replace(
            "_", " "
        )

    if field.field_info.title:
        schema_overrides = True

    if field.field_info.description:
        schema["description"] = field.field_info.description
        schema_overrides = True

    if not field.required and not field.field_info.const and field.default is not None:
        schema["default"] = encode_default(field.default)
        schema_overrides = True

    return schema, schema_overrides


# Traceback (TypeError)
from pydantic import BaseModel, Field
from typing import Callable
class Foo(BaseModel):
...     # without default value, getting user warning
...     callback: Callable[[], dict]
...
Foo.schema()
__main__:1: UserWarning: Callable callback was excluded from schema since JSON schema has no equivalent type.
{'title': 'Foo', 'type': 'object', 'properties': {}}

class FooDefault(BaseModel):
...     callback: Callable[[], dict] = Field(default=lambda: {'some': 'data'})
FooDefault.schema()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "pydantic/main.py", line 637, in pydantic.main.BaseModel.schema
File "pydantic/schema.py", line 153, in pydantic.schema.model_schema
File "pydantic/schema.py", line 523, in pydantic.schema.model_process_schema
File "pydantic/schema.py", line 564, in pydantic.schema.model_type_schema
File "pydantic/schema.py", line 215, in pydantic.schema.field_schema
File "pydantic/schema.py", line 183, in pydantic.schema.get_field_info_schema
File "pydantic/schema.py", line 846, in pydantic.schema.encode_default
File "pydantic/json.py", line 65, in pydantic.json.pydantic_encoder
TypeError: Object of type 'function' is not JSON serializable

# Fixed code
def get_field_info_schema(field: ModelField) -> Tuple[Dict[str, Any], bool]:
    schema_overrides = False

    # If no title is explicitly set, we don't set title in the schema for enums.
    # The behaviour is the same as `BaseModel` reference, where the default title
    # is in the definitions part of the schema.
    schema: Dict[str, Any] = {}
    if field.field_info.title or not lenient_issubclass(field.type_, Enum):
        schema["title"] = field.field_info.title or field.alias.title().replace(
            "_", " "
        )

    if field.field_info.title:
        schema_overrides = True

    if field.field_info.description:
        schema["description"] = field.field_info.description
        schema_overrides = True

    if (
        not field.required
        and not field.field_info.const
        and field.default is not None
        and not is_callable_type(field.outer_type_)
    ):
        schema["default"] = encode_default(field.default)
        schema_overrides = True

    return schema, schema_overrides