Summary

Add a common mixin class for handling invalidation.

Review Request #15170 — Created July 15, 2026 and updated July 15, 2026, 8:58 a.m.

Information

Owner

chipx86

Repository

cryptozoology

Branch

master

Bugs

Depends On

Blocks

15168, 15172

Reviewers

Groups

beanbag-misc

People

Description

Sensitive data (keys, secrets) are intended to be invalidated early,

keeping the data safe and out of memory as best as possible.
This class implements this as a mixin class. It handles invalidation

when the instance falls out of scope, and allows the object to be used

as a context manager, invalidating on exit.

Testing Done

Unit tests pass.

Commits

Summary	ID
Add a common mixin class for handling invalidation. Sensitive data (keys, secrets) are intended to be invalidated early, keeping the data safe and out of memory as best as possible. This class implements this as a mixin class. It handles invalidation when the instance falls out of scope, and allows the object to be used as a context manager, invalidating on exit.	7545462ea83693d7a39ab6c19687196949dfcf3d

Issues

Description	From	Last Updated
Instead of methods that raise NotImplementedError, how about subclassing abc.ABC and marking those with @abstractmethod?	david	July 15, 2026, 8:58 a.m.
Should probably change this to say self?	david	July 15, 2026, 8:58 a.m.
__exit__ never gets called with kwargs. Can we use the standard signature? def __exit( self, exc_type: type[BaseException] \| None, exc_value: …	david	July 15, 2026, 8:58 a.m.
If a subclass raises an exception from __init__, __del__ could get called on a partially-constructed instance. If the implementation of …	david	July 15, 2026, 8:58 a.m.
It's harmless here, but just to model goot behavior, can we call super().__init__()?	david	July 15, 2026, 8:58 a.m.
Since this is greenfield, can we use pytest test cases and real docstrings instead of a UnitTest subclass?	david	July 15, 2026, 8:58 a.m.
typo: exceptio -> exception	david	July 15, 2026, 8:58 a.m.
This was copy/pasted without updating to match the test.	david	July 15, 2026, 8:58 a.m.

flake8 passed.

JSHint passed.

Change Summary:

Removed the changes to BaseKey. Changing the order of commits.

Commits:

	Summary	ID
	Add a common mixin class for handling invalidation. Sensitive data (keys, secrets) are intended to be invalidated early, keeping the data safe and out of memory as best as possible. This class implements this as a mixin class. It handles invalidation when the instance falls out of scope, and allows the object to be used as a context manager, invalidating on exit.	e713456079169d085dbd89d8a9e54ae804b475cf
	Add a common mixin class for handling invalidation. Sensitive data (keys, secrets) are intended to be invalidated early, keeping the data safe and out of memory as best as possible. This class implements this as a mixin class. It handles invalidation when the instance falls out of scope, and allows the object to be used as a context manager, invalidating on exit.	7545462ea83693d7a39ab6c19687196949dfcf3d

Diff:

Revision 2 (+294)

Show changes

	cryptozoology/utils/invalidation.py
	cryptozoology/utils/tests/test_invalidatable_mixin.py

Checks run (2 succeeded)

flake8 passed.

JSHint passed.

Fix it!

cryptozoology/utils/invalidation.py (Diff revision 2)

An issue was opened. Show all issues

Instead of methods that raise NotImplementedError, how about subclassing abc.ABC and marking those with @abstractmethod?

cryptozoology/utils/invalidation.py (Diff revision 2)
An issue was opened. Show all issues
```
Should probably change this to say self?
```

cryptozoology/utils/invalidation.py (Diff revision 2)

An issue was opened. Show all issues

__exit__ never gets called with kwargs. Can we use the standard signature?

def __exit(
    self,
    exc_type: type[BaseException] | None,
    exc_value: BaseException | None,
    traceback: TracebackType | None,
) -> None:

cryptozoology/utils/invalidation.py (Diff revision 2)

An issue was opened. Show all issues

If a subclass raises an exception from __init__, __del__ could get called on a partially-constructed instance. If the implementation of invalidate() then assumes an attribute it set, it will AttributeError, and python will silently swallow it (I think it prints to stderr, but that's not the best for a library). This could leave the object not fully invalidated.

Can we document in here that the implementation must be able to handle partially-constructed instances, and cannot assume that all attributes have been set?

We also should document that this method needs to be idempotent, since it can get called first from __exit__ and then again from __del__

cryptozoology/utils/tests/test_invalidatable_mixin.py (Diff revision 2)

An issue was opened. Show all issues

It's harmless here, but just to model goot behavior, can we call super().__init__()?

cryptozoology/utils/tests/test_invalidatable_mixin.py (Diff revision 2)

An issue was opened. Show all issues

Since this is greenfield, can we use pytest test cases and real docstrings instead of a UnitTest subclass?

cryptozoology/utils/tests/test_invalidatable_mixin.py (Diff revision 2)
An issue was opened. Show all issues
```
typo: exceptio -> exception
```
cryptozoology/utils/tests/test_invalidatable_mixin.py (Diff revision 2)
An issue was opened. Show all issues
```
This was copy/pasted without updating to match the test.
```