Re: The Case for Rust (in the base system)

On Sun, Jan 21, 2024 at 2:32 PM Warner Losh <imp@bsdimp.com> wrote:
>
>
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> On Sun, Jan 21, 2024, 2:04 PM Alan Somers <asomers@freebsd.org> wrote:
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>> On Sun, Jan 21, 2024 at 1:13 PM Poul-Henning Kamp <phk@phk.freebsd.dk> wrote:
>> >
>> > --------
>> > Warner Losh writes:
>> >
>> > > Even if all the cool kids are doing it, it doesn't mean the cool kids are
>> > > wrong. We should not reject the hypothesis on that basis alone.
>> >
>> > I certainly didn't mean to imply that, my point about cvsup was precisely
>> > that the proof of the pudding is in the eating.
>> >
>> > The only comment I want to add, is that the test-cases should be
>> > expressed such that, if/when we find out Rust wasn't God's gift to
>> > programmers, we can reimplement the tool which interprets them in
>> > some hot-language-du-jour, without having to rewrite all the actual
>> > test-cases.
>>
>> I think imp and phk are after different things.  phk wants a tool
>> written in Rust that be installed from ports and interpret test cases
>> defined in src.  That's similar to the fsx tests, which I'm planning
>> to add to src once the package builder catches up.  But imp wants test
>> cases that are actually written in Rust and which live in src, to test
>> his external toolchain proposal.  That's very different.  It's an
>> unusual requirement.  Off hand I can't think of many subsystems that
>> are a good match for a test suite like that.  ypclnt(3) might be one.
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>
> Hmmm, I'd kinda thought you wanted to rewrite fsx in rust and use it
> as part of the kyua tests, much like io.cc simulates some of the things
> fsx does. I didn't care about the details of whether it was a test case,
> used by test cases or interprets the results. It really doesn't matter to
> me beyond (a) it's used to test the system or some aspect of the system
> and (b) it's written in rust and compiled when we generally compile the
> other tests and test-like things. I thought this was exactly what you were
> proposing as one of the things that would show how writing it in rust
> would give us some benefit.
>
> But to be honest, I'm agnostic about how the 'build rust things in base
> via external toolchain' stuff is used for. The important thing is that something
> non-critical be selected as a pilot project to see whether the hassles of
> adding this, maintaining the port, and the resulting better outcomes
> because it's in rust. I proposed something related to testing (the (a) above)
> because that's well segregated from the rest of the system and it's
> something that could be redone, in all likelihood, in some other language
> should the need arise. I had thought fsx and fsx-rs would provide a nice
> compare and contrast study if they gave us approximately the same things.
>
> And besides, it's just my opinion of what project would be both useful and produce
> good data about using Rust in the base. I'm sure others could be proposed
> as well.
>
> Warner

The fsx rewrite is already complete and it's in ports.  I don't see
any benefit to bringing it back to src other than to test your
external toolchain proposal.  Do you still want to do it?