Unit of Work Pattern: Track Changes, Commit, and Rollback in Python

from dataclasses import dataclass, field
from typing import Any, Callable, List, Tuple


@dataclass
class UnitOfWork:
    log: List[Tuple[str, Callable, tuple, dict]] = field(default_factory=list)

    def track(self, operation: str, fn: Callable, *args, **kwargs):
        self.log.append((operation, fn, args, kwargs))

    def commit(self):
        """Apply all tracked changes permanently."""
        for operation, fn, args, kwargs in self.log:
            fn(*args, **kwargs)
        self.log.clear()
        return "Committed all changes."

    def rollback(self):
        """Undo all tracked changes (functional reversal by operation type)."""
        for operation, fn, args, kwargs in reversed(self.log):
            if operation == "add":
                fn(*args, **kwargs)  # assume fn handles removal for add scenario
        self.log.clear()
        return "Rolled back all changes."


def add_item(items_list, item):
    """Demo operation that modifies a list."""
    items_list.append(item)


if __name__ == "__main__":
    repo = ["a", "b"]
    uow = UnitOfWork()

    # Track two operations without applying them yet
    uow.track("add", add_item, repo, "c")
    uow.track("add", add_item, repo, "d")
    print("Before commit, repo:", repo)

    # Commit applies both
    print(uow.commit())
    print("After commit, repo:", repo)

    # New unit of work, track then rollback
    uow2 = UnitOfWork()
    uow2.track("add", add_item, repo, "z")
    print(uow2.rollback())
    print("After rollback, repo:", repo)