Re: [PULL 12/40] rust: build integration test for the qemu_api crate

[Bernhard Beschow]

Am 20. Dezember 2024 10:42:09 UTC schrieb Paolo Bonzini <pbonzini@redhat.com>:
>
>
>On Thu, Dec 19, 2024 at 12:22 PM Paolo Bonzini <pbonzini@redhat.com> wrote:
>> 
>> On 12/19/24 10:53, Bernhard Beschow wrote:
>> >
>> >
>> > Am 4. November 2024 17:26:51 UTC schrieb Paolo Bonzini 
>> > <pbonzini@redhat.com>:
>> >> Adjust the integration test to compile with a subset of QEMU object
>> >> files, and make it actually create an object of the class it defines.
>> >>
>> >> Follow the Rust filesystem conventions, where tests go in tests/ if
>> >> they use the library in the same way any other code would.
>> >>
>> >> Reviewed-by: Junjie Mao <junjie.mao@hotmail.com>
>> >> Reviewed-by: Kevin Wolf <kwolf@redhat.com>
>> >> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
>> >> ---
>> >> meson.build                  | 10 ++++-
>> >> rust/qemu-api/meson.build    | 26 ++++++++++--
>> >> rust/qemu-api/src/lib.rs     |  3 --
>> >> rust/qemu-api/src/tests.rs   | 49 ----------------------
>> >> rust/qemu-api/tests/tests.rs | 78 ++++++++++++++++++++++++++++++++++++
>> >> 5 files changed, 110 insertions(+), 56 deletions(-)
>> >> delete mode 100644 rust/qemu-api/src/tests.rs
>> >> create mode 100644 rust/qemu-api/tests/tests.rs
>> >
>> > When `--enable-modules` is passed to configure, this patch results in 
>> > numerous undefined symbols.
>> 
>> Thanks for the report... This doesn't seem easy to fix without adding
>> more hacks on top, but I'll try to do it right.
>
>Which might very well be doing it in Meson.  One needs to teach Meson
>to add --start-group/--end-group options for rustc just like Meson does
>for the C compiler; or alternatively to support "objects: ..." for
>Rust executables.
>
>For example, with https://github.com/mesonbuild/meson/pull/14026, the fix
>is simply this:
>
>diff --git a/rust/qemu-api/meson.build b/rust/qemu-api/meson.build
>index 9425ba7100c..0c08d2e51f5 100644
>--- a/rust/qemu-api/meson.build
>+++ b/rust/qemu-api/meson.build
>@@ -59,7 +59,8 @@ test('rust-qemu-api-integration',
>         rust_args: ['--test'],
>         install: false,
>         dependencies: [qemu_api, qemu_api_macros],
>-        link_whole: [rust_qemu_api_objs, libqemuutil]),
>+        link_with: libqemuutil,
>+        link_whole: [rust_qemu_api_objs]),
>     args: [
>         '--test', '--test-threads', '1',
>         '--format', 'pretty',
>
>Until then, --enable-modules is broken together with Rust.

Thanks for figuring this out! Your latest patches really motivated me to try 
out the Rust support. I especially liked the patch leveraging GATs for storing 
metadata inside the type system which seems like idiomatic Rust to me. Great 
work!

Best regards,
Bernhard

>
>Paolo
>