I agree re Rust vs C - this is not (only) a language issue. What would (roughly) the invariant be here?

In another thread comment below i argue that maybe the system (OS) itself is so complex that it lacks clear contract / the contract evolves too quickly over time (as other parts of the code need to change the given piece of code to extend it to their use case) and that defies clear encoding?

Or we lack easy enough means to describe specs? I tried reading jepsen spec earlier today and despite it being an "integration test" of sorts, it is far from "simple".

Can an entire OS or a system of comparable complexity be decomposed into objects simple enough that their entire intended behavior (with all edge cases) can be explained in a paragraph of human text + half a screen of dense behavioral "spec" - if i do X and do Y, Z should come out / hold _no matter what happens in-between_. Or that's what asserts + fuzzing is effectively supposed to do? Is there a clear distinction between invalid input and failed invariant in typical C code? I guess error code vs seg fault?

This is in effect a state machine, and when you have a type system more complex than C's you can encode state transitions in the type system (either by having state transitions explicitly return a new return type or by using sum types). You still need to architect the system to encode the invariants in types. No language will fix all logic bugs for free. But you can leverage language features to reduce their number.

If you think open source is bad, wait till you see enterprise code. I'm talking full auth bypass due to the stupidest crap. You can do that in any language if you have fools working on the code base.

Yes, I agree. I find the addition of the regression test the true long-term fix. The code is just an opaque incantation that may or may not preserve some property we find worth preserving and we have no way of knowing it keeps preserving it over time as other parts of the system change.

The test actually proves it and while it too can change it has more staying power because it's expressed at a higher level of abstraction ("random arcane weird C shit" in the case of code versus "does this property hold" in the case of a regression test).

On the other hand, it is (both halting and spec adherence) are checkable under compute and space constraints though? :) I'd say the biggest hurdle are means to describe the spec in way that is easy enough for a human to produce to make it feasible.

Not a DB person either, but things like TLA+ seem very hard to write even with LLMs. Behavioral tests with an enumerable number of random paths to take (aka model checking - eg jepsen) seem more feasible. Although you can't check internal properties of the system (string `pass` or any of it's copies or parts are not held anywhere in memory at any point between lines A and B) unless we can check that two memory dumps are indistinguishable with different pass strings (assuming we abstracted away storage devices in a test environment).. Also not sure if it's "easy enough" to write such tests either.

Maybe the reason is that OS domain objects / primitives are too complex and not "isolatable" enough / lack a clear contract at all? (Hence multi file refactorings that break invariants.)

Not sure why you're getting downvoted, this is the entire point of open source.

Does such a bug exist in Windows? OSX? Who checks? If someone finds the key in memory, can they tell what conditions might be causing it and where?

Their only recourse under those situations is to hand it off to the OS Vendor and trust that what they implement does solve the problem, and trust that it wasn't a deliberate back-door that is now being replaced by another back-door.