Re: [PATCH v2 0/5] Introduce Owned type and Ownable trait (was: "rust: page: Add support for vmalloc_to_page")

[Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>]

On Wed, Oct 23, 2024 at 10:03 AM Danilo Krummrich <dakr@kernel.org> wrote:
>
> I wonder if it would make sense to make `CLIPPY=1` the default and only disable
> it by explicitly passing `CLIPPY=0`.

That is what I wanted, but when I asked long ago to the Clippy
maintainers if using `clippy-driver` was guaranteed to not affect
codegen, the answer was no: for instance, optimization may be affected
(at least back then), and the maintainers said the intention is that
is not to be used for normal compiling. So I sent a PR to document
that. See:

    https://github.com/rust-lang/rust-clippy/issues/8035
    https://github.com/rust-lang/rust-clippy/pull/8037

Similarly, Christian proposed running `rustfmtcheck` unconditionally
on build and offering a way to turn it off instead. I think that would
be ideal too, but it could potentially lead to problems too, so I am
not sure either; see e.g.:

    https://lore.kernel.org/rust-for-linux/CANiq72==AkkqCDaZMENQRg8cf4zdeHpTHwdWS3sZiFWm0vyJUA@mail.gmail.com/

So I wonder if we should instead go with a "dev mode" like `D=1` that
enables Clippy, `rustfmtcheck`, `-Dwarnings` (even if `WERROR=n` and
applying to everything, not just kernel objects,), potentially
`rustdoc`-related warnings too, and whatever other tooling/checks in
the future (e.g. klint), and not just for Rust but potentially for C
and other bits too (e.g. `W=1`, some important subset of Coccinelle
scripts...).

That way, "normal builds" (i.e. those done by users) stay as
fast/clean/warning-free/bug-free/optimized as possible even across
compiler versions, potential bugs in the toolchain, etc. And I imagine
it would be easier for newcomers, too.

Opinions welcome! I am happy to prepare an RFC, since it seems a few
people would like something like that.

Cheers,
Miguel