dict_diff.py

from typing import Iterable

def dict_diff(
    old: dict,
    new: dict,
    ignore_keys: Iterable[str] = [],
    include_keys: Iterable[str] = []
) -> dict:
    """Capture changes between dictionaries.

    Additions, updates and deletions respectively:

    >>> dict_diff({}, {'b': 2})
    {'b': 2}
    >>> dict_diff({'a': 1}, {'a': 2})
    {'a': 2}
    >>> dict_diff({'a': 1}, {})
    {'a': None}
    """
    ignore_keys, include_keys = list(ignore_keys), list(include_keys)
    if include_keys:
        if both := set(ignore_keys).intersection(include_keys):
            raise ValueError(
                f"Keys can't be in both ignore_keys and include_keys: {both}")
        ignore_keys = list(
            set(old)
            .union(new)
            .difference(set(include_keys))
        )
    fz_old = frozenset(sorted([
        (k, v) for k, v in old.items()
        if k not in ignore_keys
    ]))
    fz_new = frozenset(sorted([
        (k, v) for k, v in new.items()
        if k not in ignore_keys
    ]))
    old_updated_or_deleted = dict(fz_old.difference(fz_new))
    new_updates = dict(fz_new.difference(fz_old))
    deleted = {
        k: None for k, _ in old_updated_or_deleted.items()
        if k not in new_updates
    }
    new_updates |= deleted
    return new_updates