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Hyrum’s Law in Golang

(abenezer.org)
313 points thunderbong | 8 comments | 21 Nov 24 07:12 UTC | HN request time: 1.023s | source | bottom
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hambes ◴[21 Nov 24 08:20 UTC] No.42202204[source]▶
Solution to the specifically mentioned problem: Don't use string-based errors, use sentinel errors [1].

More generally: Don't produce code where consumers of your API are the least bit inclined to rely on non-technical strings. Instead use first-level language constructs like predefined error values, types or even constants that contain the non-technical string so that API consumers can compare the return value againnst the constant instead of hard-coding the contained string themselves.

Hyrum's Law is definitely a thing, but its effects can be mitigated.

[1]: https://thomas-guettler.de/go/wrapping-and-sentinel-errors

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Svip ◴[21 Nov 24 08:29 UTC] No.42202257[source]▶
In your example, the onus is on the consumer not the provider. I could still be writing code that checks if `err.String() == "no more tea available."`. I agree, I shouldn't do that, but nothing is preventing me from doing that. Additionally, errors.Is is a relatively recent addition to Go, so by the time people would check for errors like this, it was just easier to check the literal string. But as an API provider in Go, you cannot prevent your consumers from checking the return values of .String().
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hambes ◴[21 Nov 24 08:35 UTC] No.42202284[source]▶
Unfortunately true. The Go maintainers might not agree with me on this, but I think in this case consumers have to learn the hard way. Go tries to always be backwards compatible, but I don't think that trying to be backwards compatible with incorrect usage is ever the right choice.
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LudwigNagasena ◴[21 Nov 24 10:18 UTC] No.42202783[source]▶
So the people who decided to make a stringly type error with `errors.New("http: request body too large")` and make you suffer, now can remove a stringly typed error and make you suffer even more? What would the lesson be? What would consumers learn?
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hambes ◴[21 Nov 24 12:28 UTC] No.42203648[source]▶
I don't understand your point. The lesson is "don't rely on magic strings, instead rely on exported and documented constants, otherwise your code might break".
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1. LudwigNagasena ◴[21 Nov 24 13:11 UTC] No.42203983[source]▶
My point is that a few years ago there was no exported and document constant. The lesson should be "provide sensible tools, otherwise your consumers will have to rely on implementation details for the most basic expected stuff".
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2. ◴[21 Nov 24 14:07 UTC] No.42204421[source]▶
3. stonemetal12 ◴[21 Nov 24 15:17 UTC] No.42205117[source]▶
>My point is that a few years ago there was no exported and document constant.

Then the feature didn't exist. Figuring out undocumented implementation details to "make it work" is asking for it to be broken in the future. So if you are unwilling or unable to support fixing it in the future then don't do that.

If it is "the most basic expected stuff" then quite literally make the determination that it isn't ready for use. A lot of Go was and maybe still be half baked and not ready for production. It is ok to recognize that and not use it.

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4. Joker_vD ◴[21 Nov 24 17:00 UTC] No.42206288[source]▶
I am glad that your circumstances are such that you can just stop working on a project when the tooling it uses turns out to be inadequate, wait five years, and then come back when it improves.

Unfortunately, many people can't really do that: when the ecosystem turns out to be somewhat inadequate in a project that's already been in use for couple of years, their options are either "just make it work one way or another, who cares if it's a hardcoded string, we have to ship the fix ASAP" or "rewrite it all in Rust/X, allegedly their ecosystem is production-ready".

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5. estebarb ◴[21 Nov 24 19:44 UTC] No.42207854[source]▶
That is the kind of stuff I would have expected `go vet` to fix.
6. dwattttt ◴[21 Nov 24 21:53 UTC] No.42209077{3}[source]▶
> "just make it work one way or another, who cares if it's a hardcoded string, we have to ship the fix ASAP"

Sure, but now that there's a "correct" way to do this, you don't get to complain that the hacky thing you did needs to keep being supported. You fix the hacky thing you did, or you make peace that you're still doing the hacky thing, problems it causes and all.

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7. outworlder ◴[22 Nov 24 03:11 UTC] No.42210792{3}[source]▶
> I am glad that your circumstances are such that you can just stop working on a project when the tooling it uses turns out to be inadequate, wait five years, and then come back when it improves.

Is it that terrible to just handle an error as an error, without having to know exactly what the error was? If you see some of the codebases which rely on the error, they are trying to be too clever and doing things like returning a 400 instead of 500 if that's the specific error message returned. Is that really necessary?

Unless the codebase can take corrective actions (and it could still attempt to do it regardless if that's the case), there's really no point trying to be cute. An error is returned, and that's that.

8. beautron ◴[22 Nov 24 08:06 UTC] No.42212001{4}[source]▶
I love that the Go project takes compatibility so seriously. And I think taking Hyrum's Law into account is necessary, if what you're serious about is compatibility itself.

Being serious about compatibility allows the concept of a piece of software being finished. If I finished writing a book twelve years ago, you could still read it today. But if I finished writing a piece of software twelve years ago, could you still build and run it today? Without having to fix anything? Without having to fix lots of things?

> Sure, but now that there's a "correct" way to do this, you don't get to complain that the hacky thing you did needs to keep being supported.

But that's the whole point and beauty of Go's compatibility promise. Once you finish getting something working, you finished getting it working. It works.

What I don't want, is for my programming platform to suddenly say that the way I got the thing working is no longer supported. I am no longer finished getting it working. I will never be finished getting it working.

Go is proving that a world with permanently working software is possible (vs a world with software that breaks over time).