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confingy.serde#

serde #

SerializationKeys #

Constants for serialization markers in the serialized data.

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class SerializationKeys:
    """Constants for serialization markers in the serialized data."""

    CLASS = "_confingy_class"
    MODULE = "_confingy_module"
    LAZY = "_confingy_lazy"
    CONFIG = "_confingy_config"
    INIT = "_confingy_init"
    DATACLASS = "_confingy_dataclass"
    FIELDS = "_confingy_fields"
    CALLABLE = "_confingy_callable"
    TRACKED_INFO = "_confingy_tracked_info"
    UNSERIALIZABLE = "_confingy_unserializable"
    OBJECT = "_confingy_object"
    METHOD = "_confingy_method"
    NAME = "_confingy_name"
    CLASS_HASH = "_confingy_class_hash"
    ENUM = "_confingy_enum"
    TUPLE = "_confingy_tuple"
    SET = "_confingy_set"
    ITEMS = "_confingy_items"

SerializationHandler #

Bases: ABC

Abstract base class for serialization handlers.

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class SerializationHandler(ABC):
    """Abstract base class for serialization handlers."""

    @abstractmethod
    def can_handle(self, obj: Any) -> bool:
        """Check if this handler can serialize the given object."""
        pass

    @abstractmethod
    def serialize(self, obj: Any, context: "SerializationContext") -> Any:
        """Serialize the object."""
        pass

    @abstractmethod
    def deserialize(self, data: Any, context: "DeserializationContext") -> Any:
        """Deserialize the data."""
        pass

    def map_children(self, obj: Any, fn: "Callable[[Any], Any]") -> Any:
        """Apply fn to all child values, returning new object with transformed children.

        This enables recursive traversal of nested structures for operations like
        lens/unlens without duplicating container-specific logic.

        Default returns obj unchanged (for leaf types like primitives).
        """
        return obj

can_handle abstractmethod #

can_handle(obj: Any) -> bool

Check if this handler can serialize the given object.

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@abstractmethod
def can_handle(self, obj: Any) -> bool:
    """Check if this handler can serialize the given object."""
    pass

serialize abstractmethod #

serialize(obj: Any, context: SerializationContext) -> Any

Serialize the object.

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@abstractmethod
def serialize(self, obj: Any, context: "SerializationContext") -> Any:
    """Serialize the object."""
    pass

deserialize abstractmethod #

deserialize(
    data: Any, context: DeserializationContext
) -> Any

Deserialize the data.

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@abstractmethod
def deserialize(self, data: Any, context: "DeserializationContext") -> Any:
    """Deserialize the data."""
    pass

map_children #

map_children(obj: Any, fn: Callable[[Any], Any]) -> Any

Apply fn to all child values, returning new object with transformed children.

This enables recursive traversal of nested structures for operations like lens/unlens without duplicating container-specific logic.

Default returns obj unchanged (for leaf types like primitives).

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def map_children(self, obj: Any, fn: "Callable[[Any], Any]") -> Any:
    """Apply fn to all child values, returning new object with transformed children.

    This enables recursive traversal of nested structures for operations like
    lens/unlens without duplicating container-specific logic.

    Default returns obj unchanged (for leaf types like primitives).
    """
    return obj

SerializationContext #

Context for serialization operations.

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class SerializationContext:
    """Context for serialization operations."""

    def __init__(self):
        self.handlers: list[SerializationHandler] = []
        self._depth = 0
        self._max_depth = 100
        self._path: list[str] = []  # Track object path for debugging

    def register_handler(self, handler: SerializationHandler):
        """Register a serialization handler."""
        self.handlers.append(handler)

    def serialize(self, obj: Any, key: str | None = None) -> Any:
        """Serialize an object using registered handlers."""
        if key:
            self._path.append(key)

        self._depth += 1
        try:
            if self._depth > self._max_depth:
                path_str = " -> ".join(self._path)
                raise SerializationError(
                    f"Maximum recursion depth ({self._max_depth}) exceeded at path: {path_str}"
                )

            for handler in self.handlers:
                if handler.can_handle(obj):
                    return handler.serialize(obj, self)

            # Raise an error for unserializable objects
            path_str = " -> ".join(self._path) if self._path else "root"
            raise SerializationError(
                f"No handler found for type {type(obj).__name__} at path {path_str}"
            )
        except Exception as e:
            if not isinstance(e, SerializationError):
                path_str = " -> ".join(self._path) if self._path else "root"
                raise SerializationError(
                    f"Failed to serialize at path {path_str}: {e}"
                ) from e
            raise
        finally:
            self._depth -= 1
            if key:
                self._path.pop()

register_handler #

register_handler(handler: SerializationHandler)

Register a serialization handler.

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def register_handler(self, handler: SerializationHandler):
    """Register a serialization handler."""
    self.handlers.append(handler)

serialize #

serialize(obj: Any, key: str | None = None) -> Any

Serialize an object using registered handlers.

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def serialize(self, obj: Any, key: str | None = None) -> Any:
    """Serialize an object using registered handlers."""
    if key:
        self._path.append(key)

    self._depth += 1
    try:
        if self._depth > self._max_depth:
            path_str = " -> ".join(self._path)
            raise SerializationError(
                f"Maximum recursion depth ({self._max_depth}) exceeded at path: {path_str}"
            )

        for handler in self.handlers:
            if handler.can_handle(obj):
                return handler.serialize(obj, self)

        # Raise an error for unserializable objects
        path_str = " -> ".join(self._path) if self._path else "root"
        raise SerializationError(
            f"No handler found for type {type(obj).__name__} at path {path_str}"
        )
    except Exception as e:
        if not isinstance(e, SerializationError):
            path_str = " -> ".join(self._path) if self._path else "root"
            raise SerializationError(
                f"Failed to serialize at path {path_str}: {e}"
            ) from e
        raise
    finally:
        self._depth -= 1
        if key:
            self._path.pop()

DeserializationContext #

Context for deserialization operations.

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class DeserializationContext:
    """Context for deserialization operations."""

    def __init__(self, strict: bool = True):
        """Initialize deserialization context.

        Args:
            strict: If True (default), raise an error when serialized configs contain
                kwargs that no longer exist in the class signature. If False, emit
                a warning and ignore the extra kwargs. Similar to PyTorch's
                load_state_dict strict parameter.
        """
        self.handlers: list[SerializationHandler] = []
        self._depth = 0
        self._max_depth = 100
        self.strict = strict

    def register_handler(self, handler: SerializationHandler):
        """Register a serialization handler."""
        self.handlers.append(handler)

    def deserialize(self, data: Any, expected_type: type | None = None) -> Any:
        """Deserialize data using registered handlers."""
        self._depth += 1
        try:
            if self._depth > self._max_depth:
                raise DeserializationError(
                    f"Maximum recursion depth ({self._max_depth}) exceeded"
                )

            # Primitives pass through
            if data is None or isinstance(data, int | float | str | bool):
                return data

            # Try all handlers (including collection handlers)
            for handler in self.handlers:
                result = handler.deserialize(data, self)
                if result is not None:
                    return result

            return data
        finally:
            self._depth -= 1

__init__ #

__init__(strict: bool = True)

Initialize deserialization context.

Parameters:

Name Type Description Default
strict bool

If True (default), raise an error when serialized configs contain kwargs that no longer exist in the class signature. If False, emit a warning and ignore the extra kwargs. Similar to PyTorch's load_state_dict strict parameter.

 True
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def __init__(self, strict: bool = True):
    """Initialize deserialization context.

    Args:
        strict: If True (default), raise an error when serialized configs contain
            kwargs that no longer exist in the class signature. If False, emit
            a warning and ignore the extra kwargs. Similar to PyTorch's
            load_state_dict strict parameter.
    """
    self.handlers: list[SerializationHandler] = []
    self._depth = 0
    self._max_depth = 100
    self.strict = strict

register_handler #

register_handler(handler: SerializationHandler)

Register a serialization handler.

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def register_handler(self, handler: SerializationHandler):
    """Register a serialization handler."""
    self.handlers.append(handler)

deserialize #

deserialize(
    data: Any, expected_type: type | None = None
) -> Any

Deserialize data using registered handlers.

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def deserialize(self, data: Any, expected_type: type | None = None) -> Any:
    """Deserialize data using registered handlers."""
    self._depth += 1
    try:
        if self._depth > self._max_depth:
            raise DeserializationError(
                f"Maximum recursion depth ({self._max_depth}) exceeded"
            )

        # Primitives pass through
        if data is None or isinstance(data, int | float | str | bool):
            return data

        # Try all handlers (including collection handlers)
        for handler in self.handlers:
            result = handler.deserialize(data, self)
            if result is not None:
                return result

        return data
    finally:
        self._depth -= 1

PrimitiveHandler #

Bases: SerializationHandler

Handler for primitive types.

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class PrimitiveHandler(SerializationHandler):
    """Handler for primitive types."""

    def can_handle(self, obj: Any) -> bool:
        return obj is None or isinstance(obj, int | float | str | bool)

    def serialize(self, obj: Any, context: SerializationContext) -> Any:
        return obj

    def deserialize(self, data: Any, context: DeserializationContext) -> Any:
        if self.can_handle(data):
            return data
        return None

EnumHandler #

Bases: SerializationHandler

Handler for enum types.

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class EnumHandler(SerializationHandler):
    """Handler for enum types."""

    def can_handle(self, obj: Any) -> bool:
        return isinstance(obj, enum.Enum)

    def serialize(self, obj: Any, context: SerializationContext) -> dict[str, Any]:
        cls = type(obj)
        return {
            SerializationKeys.CLASS: cls.__name__,
            SerializationKeys.MODULE: get_module_name(cls),
            SerializationKeys.ENUM: True,
            SerializationKeys.NAME: obj.name,
        }

    def deserialize(self, data: Any, context: DeserializationContext) -> Any:
        if not isinstance(data, dict):
            return None

        if not data.get(SerializationKeys.ENUM):
            return None

        if SerializationKeys.CLASS not in data or SerializationKeys.MODULE not in data:
            return None

        try:
            module = importlib.import_module(data[SerializationKeys.MODULE])
            cls = getattr(module, data[SerializationKeys.CLASS])
            return cls[data[SerializationKeys.NAME]]
        except (ImportError, AttributeError, KeyError) as e:
            raise DeserializationError(
                f"Could not recreate enum {data[SerializationKeys.MODULE]}.{data[SerializationKeys.CLASS]}.{data.get(SerializationKeys.NAME)}: {e}"
            ) from None

PathHandler #

Bases: SerializationHandler

Handler for pathlib.Path objects.

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class PathHandler(SerializationHandler):
    """Handler for pathlib.Path objects."""

    _PATH_CLASSES = (
        "Path",
        "PosixPath",
        "WindowsPath",
        "PurePath",
        "PurePosixPath",
        "PureWindowsPath",
    )

    def can_handle(self, obj: Any) -> bool:
        return isinstance(obj, Path)

    def serialize(self, obj: Any, context: SerializationContext) -> dict[str, Any]:
        return {
            SerializationKeys.CLASS: "Path",
            SerializationKeys.MODULE: "pathlib",
            SerializationKeys.NAME: str(obj),
        }

    def deserialize(self, data: Any, context: DeserializationContext) -> Any:
        if not isinstance(data, dict):
            return None
        if data.get(SerializationKeys.CLASS) not in self._PATH_CLASSES:
            return None
        if data.get(SerializationKeys.MODULE) != "pathlib":
            return None
        return Path(data.get(SerializationKeys.NAME, ""))

DatetimeHandler #

Bases: SerializationHandler

Handler for datetime stdlib leaf types.

Covers datetime.date, datetime.datetime, datetime.time, and datetime.timedelta. Serialized as a leaf using the same {_confingy_class, _confingy_module, _confingy_name} envelope as :class:PathHandler.

Wire formats::

date       -> {"_confingy_class": "date",      "_confingy_module": "datetime", "_confingy_name": "2024-01-01"}
datetime   -> {"_confingy_class": "datetime",  "_confingy_module": "datetime", "_confingy_name": "2024-01-01T12:34:56+00:00"}
time       -> {"_confingy_class": "time",      "_confingy_module": "datetime", "_confingy_name": "12:34:56"}
timedelta  -> {"_confingy_class": "timedelta", "_confingy_module": "datetime", "_confingy_name": 93784.0}

date / datetime / time use isoformat() / fromisoformat(). Exact round-trip is guaranteed for values that isoformat() itself emits on the same Python version (the only values we ever feed back in).

timedelta uses total_seconds() (float) for the wire value because the stdlib has no timedelta.fromisoformat. total_seconds() preserves microsecond resolution exactly for every timedelta representable by the stdlib; sub-microsecond inputs are already clamped at construction time.

Dispatch is by exact type(obj) rather than isinstance because datetime.datetime subclasses datetime.date — a naive isinstance check would mis-serialize datetimes as dates.

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class DatetimeHandler(SerializationHandler):
    """Handler for ``datetime`` stdlib leaf types.

    Covers ``datetime.date``, ``datetime.datetime``, ``datetime.time``, and
    ``datetime.timedelta``. Serialized as a leaf using the same
    ``{_confingy_class, _confingy_module, _confingy_name}`` envelope as
    :class:`PathHandler`.

    Wire formats::

        date       -> {"_confingy_class": "date",      "_confingy_module": "datetime", "_confingy_name": "2024-01-01"}
        datetime   -> {"_confingy_class": "datetime",  "_confingy_module": "datetime", "_confingy_name": "2024-01-01T12:34:56+00:00"}
        time       -> {"_confingy_class": "time",      "_confingy_module": "datetime", "_confingy_name": "12:34:56"}
        timedelta  -> {"_confingy_class": "timedelta", "_confingy_module": "datetime", "_confingy_name": 93784.0}

    ``date`` / ``datetime`` / ``time`` use ``isoformat()`` / ``fromisoformat()``.
    Exact round-trip is guaranteed for values that ``isoformat()`` itself emits
    on the same Python version (the only values we ever feed back in).

    ``timedelta`` uses ``total_seconds()`` (float) for the wire value because the
    stdlib has no ``timedelta.fromisoformat``. ``total_seconds()`` preserves
    microsecond resolution exactly for every ``timedelta`` representable by the
    stdlib; sub-microsecond inputs are already clamped at construction time.

    Dispatch is by exact ``type(obj)`` rather than ``isinstance`` because
    ``datetime.datetime`` subclasses ``datetime.date`` — a naive isinstance
    check would mis-serialize datetimes as dates.
    """

    # Map of exact stdlib type -> (wire class name) used for both directions.
    _TYPES = {
        datetime.datetime: "datetime",
        datetime.date: "date",
        datetime.time: "time",
        datetime.timedelta: "timedelta",
    }

    def can_handle(self, obj: Any) -> bool:
        return type(obj) in self._TYPES

    def serialize(self, obj: Any, context: SerializationContext) -> dict[str, Any]:
        cls = type(obj)
        if cls is datetime.timedelta:
            name: Any = obj.total_seconds()
        else:
            name = obj.isoformat()
        return {
            SerializationKeys.CLASS: self._TYPES[cls],
            SerializationKeys.MODULE: "datetime",
            SerializationKeys.NAME: name,
        }

    def deserialize(self, data: Any, context: DeserializationContext) -> Any:
        if not isinstance(data, dict):
            return None
        if data.get(SerializationKeys.MODULE) != "datetime":
            return None
        class_name = data.get(SerializationKeys.CLASS)
        name = data.get(SerializationKeys.NAME)
        if class_name in ("date", "datetime", "time"):
            if not isinstance(name, str):
                return None
            if class_name == "date":
                return datetime.date.fromisoformat(name)
            if class_name == "datetime":
                return datetime.datetime.fromisoformat(name)
            return datetime.time.fromisoformat(name)
        if class_name == "timedelta":
            if not isinstance(name, (int, float)):
                return None
            return datetime.timedelta(seconds=float(name))
        return None

LazyHandler #

Bases: SerializationHandler

Handler for Lazy objects.

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class LazyHandler(SerializationHandler):
    """Handler for Lazy objects."""

    def can_handle(self, obj: Any) -> bool:
        return hasattr(obj, "_confingy_lazy_info")

    def serialize(self, obj: Any, context: SerializationContext) -> dict[str, Any]:
        result = {
            SerializationKeys.CLASS: obj._confingy_lazy_info["class"],
            SerializationKeys.MODULE: obj._confingy_lazy_info["module"],
            SerializationKeys.LAZY: True,
            SerializationKeys.CONFIG: {
                k: context.serialize(v, k) for k, v in obj._confingy_config.items()
            },
        }
        # Include class_hash if available
        if "class_hash" in obj._confingy_lazy_info:
            result[SerializationKeys.CLASS_HASH] = obj._confingy_lazy_info["class_hash"]
        return result

    def deserialize(self, data: dict[str, Any], context: DeserializationContext) -> Any:
        # Only handle dictionaries
        if not isinstance(data, dict):
            return None

        if not (
            data.get(SerializationKeys.LAZY)
            and SerializationKeys.CLASS in data
            and SerializationKeys.MODULE in data
        ):
            return None

        try:
            module = importlib.import_module(data[SerializationKeys.MODULE])
            cls = getattr(module, data[SerializationKeys.CLASS])
            actual_cls = getattr(cls, "_original_cls", cls)

            config = {
                k: context.deserialize(v)
                for k, v in data.get(SerializationKeys.CONFIG, {}).items()
            }

            # Filter out extra kwargs that no longer exist in the class signature
            config = _filter_extra_kwargs(
                actual_cls,
                config,
                context.strict,
                f"{data[SerializationKeys.MODULE]}.{data[SerializationKeys.CLASS]}",
            )

            return Lazy(
                actual_cls, config, skip_validation=True, _skip_post_config_hook=True
            )
        except (ImportError, AttributeError) as e:
            raise DeserializationError(
                f"Could not recreate {data[SerializationKeys.MODULE]}.{data[SerializationKeys.CLASS]}: {e}"
            ) from None

TrackedInstanceHandler #

Bases: SerializationHandler

Handler for tracked objects.

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class TrackedInstanceHandler(SerializationHandler):
    """Handler for tracked objects."""

    def can_handle(self, obj: Any) -> bool:
        return hasattr(obj, "_tracked_info")

    def serialize(self, obj: Any, context: SerializationContext) -> dict[str, Any]:
        info = obj._tracked_info
        result = {
            SerializationKeys.CLASS: info["class"],
            SerializationKeys.MODULE: info["module"],
            SerializationKeys.INIT: {
                k: context.serialize(v, k) for k, v in info["init_args"].items()
            },
        }
        # Include class_hash if available
        if "class_hash" in info:
            result[SerializationKeys.CLASS_HASH] = info["class_hash"]
        return result

    def deserialize(self, data: dict[str, Any], context: DeserializationContext) -> Any:
        # Only handle dictionaries
        if not isinstance(data, dict):
            return None

        if (
            SerializationKeys.INIT not in data
            or SerializationKeys.CLASS not in data
            or SerializationKeys.MODULE not in data
        ):
            return None

        try:
            module = importlib.import_module(data[SerializationKeys.MODULE])
            cls = getattr(module, data[SerializationKeys.CLASS])
            actual_cls = getattr(cls, "_original_cls", cls)

            init_args = {
                k: context.deserialize(v)
                for k, v in data[SerializationKeys.INIT].items()
            }

            # Filter out extra kwargs that no longer exist in the class signature
            init_args = _filter_extra_kwargs(
                actual_cls,
                init_args,
                context.strict,
                f"{data[SerializationKeys.MODULE]}.{data[SerializationKeys.CLASS]}",
            )

            # Use _create_tracked_instance to add tracking info to the instance
            # without globally modifying the class. This allows re-serialization
            # even if the class wasn't decorated with @track.
            return _create_tracked_instance(actual_cls, (), init_args, _validate=False)
        except (ImportError, AttributeError) as e:
            raise DeserializationError(
                f"Could not recreate {data[SerializationKeys.MODULE]}.{data[SerializationKeys.CLASS]}: {e}"
            ) from None

TypeHandler #

Bases: SerializationHandler

Handler for type objects.

Source code in src/confingy/serde.py 
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class TypeHandler(SerializationHandler):
    """Handler for type objects."""

    def can_handle(self, obj: Any) -> bool:
        return isinstance(obj, type)

    def serialize(self, obj: Any, context: SerializationContext) -> dict[str, Any]:
        # Check if the class can be imported
        if (
            hasattr(obj, "__module__")
            and hasattr(obj, "__qualname__")
            and (
                # Ensure it's not a local or lambda class
                "<locals>" not in obj.__qualname__
                and "<lambda>" not in obj.__qualname__
            )
        ):
            return {
                SerializationKeys.CLASS: "type",
                SerializationKeys.MODULE: get_module_name(obj),
                SerializationKeys.NAME: obj.__qualname__,
            }

        # Raise error for unserializable types
        raise SerializationError(
            f"Cannot serialize type {obj!r}: local or lambda types are not serializable. "
            f"Define the class at module level to make it serializable."
        )

    def deserialize(self, data: dict[str, Any], context: DeserializationContext) -> Any:
        # Only handle dictionaries
        if not isinstance(data, dict):
            return None

        # Check if this is a type serialization
        if data.get(SerializationKeys.CLASS) != "type":
            return None

        # Import and return the type
        if SerializationKeys.MODULE in data and SerializationKeys.NAME in data:
            try:
                module = importlib.import_module(data[SerializationKeys.MODULE])
                parts = data[SerializationKeys.NAME].split(".")
                obj = module
                for part in parts:
                    obj = getattr(obj, part)
                return obj
            except (ImportError, AttributeError) as e:
                raise DeserializationError(
                    f"Could not import type {data[SerializationKeys.MODULE]}.{data[SerializationKeys.NAME]}: {e}"
                ) from None

        return None

CallableHandler #

Bases: SerializationHandler

Handler for callable objects.

Source code in src/confingy/serde.py 
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class CallableHandler(SerializationHandler):
    """Handler for callable objects."""

    def can_handle(self, obj: Any) -> bool:
        return callable(obj) and not isinstance(obj, type)

    def serialize(self, obj: Any, context: SerializationContext) -> dict[str, Any]:
        # Handle bound methods
        if hasattr(obj, "__self__") and hasattr(obj.__self__, "_tracked_info"):
            return {
                SerializationKeys.CALLABLE: "method",
                SerializationKeys.OBJECT: context.serialize(
                    obj.__self__, "bound_object"
                ),
                SerializationKeys.METHOD: obj.__name__,
            }

        # Handle standalone functions
        if (
            hasattr(obj, "__module__")
            and hasattr(obj, "__qualname__")
            and (
                "<locals>" not in obj.__qualname__
                and "<lambda>" not in obj.__qualname__
            )
        ):
            return {
                SerializationKeys.CALLABLE: "function",
                SerializationKeys.MODULE: get_module_name(obj),
                SerializationKeys.NAME: obj.__qualname__,
            }

        raise SerializationError(
            f"Cannot serialize callable {obj!r}: lambdas and local functions are not serializable. "
            f"Define the function at module level to make it serializable."
        )

    def deserialize(self, data: dict[str, Any], context: DeserializationContext) -> Any:
        # Only handle dictionaries
        if not isinstance(data, dict):
            return None

        if SerializationKeys.CALLABLE not in data:
            return None

        # Handle serializable callables
        if data[SerializationKeys.CALLABLE] == "function":
            try:
                module = importlib.import_module(data[SerializationKeys.MODULE])
                parts = data[SerializationKeys.NAME].split(".")
                obj = module
                for part in parts:
                    obj = getattr(obj, part)
                return obj
            except (ImportError, AttributeError) as e:
                raise DeserializationError(
                    f"Could not import function {data[SerializationKeys.MODULE]}.{data[SerializationKeys.NAME]}: {e}"
                ) from None

        elif data[SerializationKeys.CALLABLE] == "method":
            obj = context.deserialize(data[SerializationKeys.OBJECT])
            return getattr(obj, data[SerializationKeys.METHOD]) if obj else None

        else:
            raise DeserializationError(
                f"Unknown callable type: {data[SerializationKeys.CALLABLE]}"
            )

CollectionHandler #

Bases: SerializationHandler

Handler for collections (lists, tuples, sets, dicts).

Source code in src/confingy/serde.py 
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class CollectionHandler(SerializationHandler):
    """Handler for collections (lists, tuples, sets, dicts)."""

    def can_handle(self, obj: Any) -> bool:
        return isinstance(obj, list | tuple | set | dict)

    def serialize(self, obj: Any, context: SerializationContext) -> Any:
        if isinstance(obj, tuple):
            return {
                SerializationKeys.TUPLE: True,
                SerializationKeys.ITEMS: [
                    context.serialize(item, f"[{i}]") for i, item in enumerate(obj)
                ],
            }
        elif isinstance(obj, set):
            return {
                SerializationKeys.SET: True,
                SerializationKeys.ITEMS: [
                    context.serialize(item, f"[{i}]") for i, item in enumerate(obj)
                ],
            }
        elif isinstance(obj, list):
            return [context.serialize(item, f"[{i}]") for i, item in enumerate(obj)]
        elif isinstance(obj, dict):
            return {str(k): context.serialize(v, str(k)) for k, v in obj.items()}

    def deserialize(self, data: Any, context: DeserializationContext) -> Any:
        if isinstance(data, list):
            return [context.deserialize(item) for item in data]
        elif isinstance(data, dict):
            # Handle tuple wrapper
            if data.get(SerializationKeys.TUPLE) is True:
                return tuple(
                    context.deserialize(item)
                    for item in data.get(SerializationKeys.ITEMS, [])
                )
            # Handle set wrapper
            elif data.get(SerializationKeys.SET) is True:
                return {
                    context.deserialize(item)
                    for item in data.get(SerializationKeys.ITEMS, [])
                }
            # Only handle regular dicts, not confingy special objects
            elif not any(k.startswith("_confingy_") for k in data):
                return {k: context.deserialize(v) for k, v in data.items()}
        return None

    def map_children(self, obj: Any, fn: Callable[[Any], Any]) -> Any:
        if isinstance(obj, list):
            return [fn(v) for v in obj]
        # Check for namedtuple before tuple (namedtuple is a subclass of tuple)
        if isinstance(obj, tuple) and hasattr(type(obj), "_fields"):
            return type(obj)(*[fn(v) for v in obj])
        if isinstance(obj, tuple):
            return tuple(fn(v) for v in obj)
        if isinstance(obj, set):
            return {fn(v) for v in obj}
        if isinstance(obj, dict):
            return {k: fn(v) for k, v in obj.items()}
        return obj

DataclassHandler #

Bases: SerializationHandler

Handler for dataclass objects.

Source code in src/confingy/serde.py 
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class DataclassHandler(SerializationHandler):
    """Handler for dataclass objects."""

    def can_handle(self, obj: Any) -> bool:
        return dataclasses.is_dataclass(obj) and not isinstance(obj, type)

    def serialize(self, obj: Any, context: SerializationContext) -> dict[str, Any]:
        cls = obj.__class__
        return {
            SerializationKeys.CLASS: cls.__name__,
            SerializationKeys.MODULE: get_module_name(cls),
            SerializationKeys.DATACLASS: True,
            SerializationKeys.FIELDS: {
                field.name: context.serialize(getattr(obj, field.name), field.name)
                for field in dataclasses.fields(obj)
            },
        }

    def deserialize(self, data: dict[str, Any], context: DeserializationContext) -> Any:
        # Only handle dictionaries
        if not isinstance(data, dict):
            return None

        if not (
            data.get(SerializationKeys.DATACLASS)
            and SerializationKeys.FIELDS in data
            and SerializationKeys.CLASS in data
            and SerializationKeys.MODULE in data
        ):
            return None

        try:
            module = importlib.import_module(data[SerializationKeys.MODULE])
            cls = getattr(module, data[SerializationKeys.CLASS])

            # Deserialize field values
            field_values = {
                k: context.deserialize(v)
                for k, v in data[SerializationKeys.FIELDS].items()
            }

            # Create the dataclass instance
            return cls(**field_values)
        except (ImportError, AttributeError, TypeError) as e:
            raise DeserializationError(
                f"Could not recreate dataclass {data[SerializationKeys.MODULE]}.{data[SerializationKeys.CLASS]}: {e}"
            ) from None

    def map_children(self, obj: Any, fn: Callable[[Any], Any]) -> Any:
        if not (dataclasses.is_dataclass(obj) and not isinstance(obj, type)):
            return obj
        changes = {}
        for field in dataclasses.fields(obj):
            # Skip init=False fields - dataclasses.replace() can't handle them
            if not field.init:
                continue
            old_value = getattr(obj, field.name)
            new_value = fn(old_value)
            if new_value is not old_value:
                changes[field.name] = new_value
        if changes:
            return dataclasses.replace(obj, **changes)
        return obj

HandlerRegistry #

Central registry for serialization and deserialization handlers.

Source code in src/confingy/serde.py 
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class HandlerRegistry:
    """Central registry for serialization and deserialization handlers."""

    @staticmethod
    def get_default_handlers():
        """Get the default set of handlers in the correct order."""
        return [
            PathHandler(),  # Must be before PrimitiveHandler (Path is not a primitive)
            EnumHandler(),  # Must be before PrimitiveHandler (StrEnum/IntEnum are str/int)
            DatetimeHandler(),  # Must be before PrimitiveHandler (datetime types are leaves, not primitives)
            PrimitiveHandler(),
            LazyHandler(),
            TrackedInstanceHandler(),
            DataclassHandler(),
            TypeHandler(),  # Handle type objects before callables
            CallableHandler(),
            CollectionHandler(),
        ]

get_default_handlers staticmethod #

get_default_handlers()

Get the default set of handlers in the correct order.

Source code in src/confingy/serde.py 
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@staticmethod
def get_default_handlers():
    """Get the default set of handlers in the correct order."""
    return [
        PathHandler(),  # Must be before PrimitiveHandler (Path is not a primitive)
        EnumHandler(),  # Must be before PrimitiveHandler (StrEnum/IntEnum are str/int)
        DatetimeHandler(),  # Must be before PrimitiveHandler (datetime types are leaves, not primitives)
        PrimitiveHandler(),
        LazyHandler(),
        TrackedInstanceHandler(),
        DataclassHandler(),
        TypeHandler(),  # Handle type objects before callables
        CallableHandler(),
        CollectionHandler(),
    ]