dcs_liberation/game/savecompat.py
Dan Albert c80e5b259f Allow save compat to exist for two versions.
We want to clean up eventually, but allowing it to exist in both develop
and the release branch makes cherry picks easier.
2023-05-25 22:35:50 -07:00

50 lines
1.7 KiB
Python

"""Tools for aiding in save compat removal after compatibility breaks."""
from collections.abc import Callable
from typing import TypeVar
from game.version import MAJOR_VERSION
ReturnT = TypeVar("ReturnT")
class DeprecatedSaveCompatError(RuntimeError):
def __init__(self, function_name: str) -> None:
super().__init__(
f"{function_name} has save compat code for a different major version."
)
def has_save_compat_for(
major: int,
) -> Callable[[Callable[..., ReturnT]], Callable[..., ReturnT]]:
"""Declares a function or method as having save compat code for a given version.
If the function has save compatibility for the current major version, there is no
change in behavior.
If the function has save compatibility for a *different* (future or past) major
version, DeprecatedSaveCompatError will be raised during startup. Since a break in
save compatibility is the definition of a major version break, there's no need to
keep around old save compat code; it only serves to mask initialization bugs.
Args:
major: The major version for which the decorated function has save
compatibility.
Returns:
The decorated function or method.
Raises:
DeprecatedSaveCompatError: The decorated function has save compat code for
another version of liberation, and that code (and the decorator declaring it)
should be removed from this branch.
"""
def decorator(func: Callable[..., ReturnT]) -> Callable[..., ReturnT]:
# Allow current and previous version to ease cherry-picking.
if major not in {MAJOR_VERSION - 1, MAJOR_VERSION}:
raise DeprecatedSaveCompatError(func.__name__)
return func
return decorator