Re: [RFC PATCH 00/11] rust: improved integration with cargo

["Alex Bennée" <alex.bennee@linaro.org>]

Paolo Bonzini <pbonzini@redhat.com> writes:

> While we're not sure where we'll be going in the future, for now
> using cargo remains an important part of developing QEMU Rust code.
> This is because cargo is the easiest way to run clippy, rustfmt,
> rustdoc.  Cargo also allows working with doc tests, though there are
> pretty much none yet, and provides tools such as "cargo expand".
>
> This series aims at improving the integration with cargo and
> cargo-based tooling.
>
> First, while it is currently possible to run cargo on the rust/ directory,
> but it has the issue that the bindings.rs must be placed by hand in
> the build directory.  Therefore, this series starts by allowing
> cargo to "just work" when run in a "meson devenv" environment:
>
>     meson devenv -w ../rust cargo clippy --tests
>     meson devenv -w ../rust cargo fmt

Is this meant to be the rust source root, or the root of the rust
builddir:

$ meson devenv ../../rust

ERROR: Build data file './meson-private/build.dat' references functions or classes that don't exist. This probably means that it was generated with an old version of meson. Try running from the source directory meson setup . --wipe
🕙13:05:22 alex@draig:qemu.git/builds/rust  on  review/rust-cargo-rfc [$!?] [🔴 ERROR] 
$ meson devenv rust

ERROR: Build data file './meson-private/build.dat' references functions or classes that don't exist. This probably means that it was generated with an old version of meson. Try running from the source directory meson setup . --wipe
🕙13:05:53 alex@draig:qemu.git/builds/rust  on  review/rust-cargo-rfc [$!?] [🔴 ERROR] 

>
> If you are going to use cargo repeatedly, invoking just 'meson devenv'
> will put you in a shell where commands like 'cargo clippy' just work.
> For simplicity, I am also adding two targets 'make clippy' and 'make
> rustfmt'.
>
> Secondly, one problem with mixing Cargo and meson is having to redo the
> configuration of "lints" in both sides.  This series standardizes
> on using Cargo.toml to configure the build, and bringing the flags
> over to build.ninja with extensions to the existing rustc_args.py script.
> I admit that these additions to the script are pretty large and therefore
> I'm open to scrapping the idea.  I tried to organize the changes so that
> the changes are split over multiple patches.
>
> Finally, this series adds a CI job that runs rustfmt, clippy, and
> rustdoc, including running doctests.
>
> Please send comments!
>
> Paolo
>
> Paolo Bonzini (11):
>   rust: qemu_api: do not disable lints outside bindgen-generated code
>   rust: build: move rustc_args.py invocation to individual crates
>   rust: build: restrict --cfg generation to only required symbols
>   rust: build: generate warning flags from Cargo.toml
>   rust: cargo: store desired warning levels in workspace Cargo.toml
>   rust: build: move strict lints handling to rustc_args.py
>   rust: fix a couple style issues from clippy
>   rust: build: establish a baseline of lints across all crates
>   rust: build: add "make clippy", "make rustfmt"
>   rust: fix doc test syntax
>   rust: ci: add job that runs Rust tools
>
>  meson.build                                   |  56 +++---
>  .gitlab-ci.d/buildtest-template.yml           |  14 ++
>  .gitlab-ci.d/buildtest.yml                    |  14 ++
>  rust/Cargo.toml                               |  80 ++++++++
>  rust/hw/char/pl011/Cargo.toml                 |   3 +
>  rust/hw/char/pl011/src/device.rs              |   6 +-
>  rust/hw/char/pl011/src/lib.rs                 |  18 +-
>  rust/hw/char/pl011/src/memory_ops.rs          |   4 +-
>  rust/meson.build                              |  14 ++
>  rust/qemu-api-macros/Cargo.toml               |   3 +
>  rust/qemu-api/.gitignore                      |   2 +-
>  rust/qemu-api/Cargo.toml                      |   5 +-
>  rust/qemu-api/build.rs                        |  24 ++-
>  rust/qemu-api/meson.build                     |   5 +
>  rust/qemu-api/src/bindings.rs                 |  29 +++
>  rust/qemu-api/src/lib.rs                      |  22 ---
>  rust/qemu-api/src/zeroable.rs                 |   6 +-
>  rust/qemu-api/tests/tests.rs                  |   2 +-
>  scripts/rust/rustc_args.py                    | 178 ++++++++++++++++--
>  .../dockerfiles/fedora-rust-nightly.docker    |   4 +
>  tests/lcitool/refresh                         |   4 +
>  21 files changed, 391 insertions(+), 102 deletions(-)
>  create mode 100644 rust/qemu-api/src/bindings.rs

-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro