Re: [PATCH v6 00/23] Rust support

Miguel Ojeda
2022-05-10T11:36:37Z

Hi David,

On Tue, May 10, 2022 at 6:45 AM David Gow <davidgow@google.com> wrote:
>
> I've just sent out a pull request to get this working under UML as
> well, which would simplify running these further:
> https://github.com/Rust-for-Linux/linux/pull/766

Thanks a lot!

> Yeah, these are all fair points: particularly for small doctests.
>
> Maybe having an optional name, which more significant tests could use
> to override the file:line names? That could be useful for a few of the
> larger, more often referenced tests.

Sounds reasonable. I can add support for that.

> Ugh: it's a bit ugly either way. I suspect that file:line is still
> probably better, if only because we need some way of looking up the
> test in the code if it fails. I'd hate for people to be randomly
> hashing bits of just to find out what test is failing.

One redeeming quality is that the assertion prints the line/file
number in the generated file, so it would still be possible to check
where it came from:

[13:13:43] # rust_kernel_doctest_str_rs_somehash: ASSERTION FAILED
at rust/doctests_kernel_generated.rs:2209
[13:13:43] Expected 2 > 3 to be true, but is false
[13:13:43] not ok 43 - rust_kernel_doctest_str_rs_somehash
[13:13:43] [FAILED] rust_kernel_doctest_str_rs_somehash

Another alternative is to keep the file:line information around
without embedding it into the test name, e.g. in a TAP comment or a
mapping file (which `kunit.py` could read).

But, yeah, before doing hashes or things like that, I would just go
for simplicity and keep things as they are unless some use case really
needs doctests to be stable.

> Oops: I missed that (one of the issues with testing this on a
> different machine which had a rust toolchain). Looks good to me.
>
> Ah: I didn't realise the plan was always to have crate-specific
> suites, and possibly to split things up.
>
> The KTAP output specification does actually support arbitrary nesting
> (though KUnit itself doesn't at the moment), which would potentially
> be an option if (e.g.) providing the complete module nesting made
> sense. I'm not convinced that'd make things easier to read, though.

That is useful to know in case we need it, thanks!

Cheers,
Miguel