alt Hacker NewsYes. I feel like people who are trying to push software verification have never worked on typical real-world software projects where the spec is like 100 pages long and still doesn't fully cover all the requirements and you still have to read between the lines and then requirements keep changing mid-way through the project... Implementing software to meet the spec takes a very long time and then you have to invest a lot of effort and deep thought to ensure that what you've produced fits within the spec so that the stakeholder will be satisfied. You need to be a mind-reader.
It's hard even for a human who understands the full business, social and political context to disambiguate the meaning and intent of the spec; to try to express it mathematically would be an absolute nightmare... and extremely unwise. You would literally need some kind of super intelligence... And the amount of stream-of-thought tokens which would have to be generated to arrive at a correct, consistent, unambiguous formal spec is probably going to cost more than just hiring top software engineers to build the thing with 100% test coverage of all main cases and edge cases.
Worst part is; after you do all the expensive work of formal verification; you end up proving the 'correctness' of a solution that the client doesn't want.
The refactoring required will invalidate the entire proof from the beginning. We haven't even figured out the optimal way to formally architect software that is resilient to requirement changes; in fact, the industry is REALLY BAD at this. Almost nobody is even thinking about it. I am, but I sometimes feel like I may be the only person in the world who cares about designing optimal architectures to minimize line count and refactoring diff size. We'd have to solve this problem first before we even think about formal verification of 'most software'.
Without a hypothetical super-intelligence which understands everything about the world; the risk of misinterpreting any given 'typical' requirement is almost 100%... And once we have such super-intelligence, we won't need formal verification because the super-intelligence will be able to code perfectly on the first attempt; no need to verify.
And then there's the fact that most software can tolerate bugs... If operationally important big tech software which literally has millions of concurrent users can tolerate bugs, then most software can tolerate bugs.
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The whole perspective of this argument is hard for me to grasp. I don't think anyone is suggesting that formal specs are an alternative to code, they are just an alternative to informal specs. And actually with AI the new spin is that they aren't even a mutually exclusive alternative.
A bidirectional bridge that spans multiple representations from informal spec to semiformal spec to code seems ideal. You change the most relevant layer that you're interested in and then see updates propagating semi-automatically to other layers. I'd say the jury is out on whether this uses extra tokens or saves them, but a few things we do know. Chain of code works better than chain of thought, and chain-of-spec seems like a simple generalization. Markdown-based planning and task-tracking agent workflows work better than just YOLOing one-shot changes everywhere, and so intermediate representations are useful.
It seems to me that you can't actually get rid of specs, right? So to shoot down the idea of productive cooperation between formal methods and LLM-style AI, one really must successfully argue that informal specs are inherently better than formal ones. Or even stronger: having only informal specs is better than having informal+formal.
I agree that trying to produce this sort of spec for the entire project is probably a fool's errand, but I still see the value for critical components of the system. Formally verifying the correctness of balance calculation from a ledger, or that database writes are always persisted to the write ahead log, for example.
I used to work adjacent to a team who worked from closely-defined specs for web sites, and it used to infuriate the living hell out of me. The specs had all sorts of horrible UI choices and bugs and stuff that just plain wouldn't work when coded. I tried my best to get them to implement the intent of the spec, not the actual spec, but they had been trained in one method only and would not deviate at any cost.
Software verification has gotten some use for smart contracts. The code is fairly simple, it's certain to be attacked by sophisticated hackers who know the source, and the consequence of failure is theft of funds, possibly in large amounts. 100% test coverage is no guarantee that an attack can't be found.
People spend gobs of money on human security auditors who don't necessarily catch everything either, so verification easily fits in the budget. And once deployed, the code can't be changed.
Verification has also been used in embedded safety-critical code.