Re: [RFC v3 13/32] rust: use vendored-sources - Marc-André Lureau

From: "Marc-André Lureau" <marcandre.lureau@gmail.com>
To: Ian Jackson <iwj@xenproject.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
	"Daniel P. Berrange" <berrange@redhat.com>,
	QEMU <qemu-devel@nongnu.org>,
	Stefan Hajnoczi <stefanha@redhat.com>,
	Markus Armbruster <armbru@redhat.com>
Subject: Re: [RFC v3 13/32] rust: use vendored-sources
Date: Wed, 8 Sep 2021 20:20:16 +0400	[thread overview]
Message-ID: <CAJ+F1CJR9hAd+2MJZ1X9s2vBW=fG++mgk75M+Ww166orq3KdNg@mail.gmail.com> (raw)
In-Reply-To: <24888.55565.53378.616422@mariner.uk.xensource.com>

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Hi

On Wed, Sep 8, 2021 at 7:40 PM Ian Jackson <iwj@xenproject.org> wrote:

> marcandre.lureau@redhat.com writes ("[RFC v3 13/32] rust: use
> vendored-sources"):
> > Most likely, QEMU will want tighter control over the sources, rather
> > than relying on crates.io downloading, use a git submodule with all the
> > dependencies. However, cargo --offline was added in 1.36.
>
> Hi.
>
> pm215 pointed me at this, as I have some background in Rust.
> I definitely approve of having Rust in Qemu.  I don't have an opinion
> about whether the sources should be vendored this way.
>
> But, I tried to build this, and
>
>     error: failed to select a version for the requirement `cc = "=1.0.70"`
>     candidate versions found which didn't match: 1.0.69
>     location searched: directory source
> `/volatile/rustcargo/Rustup/Qemu/qemu.pwt/rust/vendored` (which is
> replacing registry `crates-io`)
>     required by package `nix v0.20.1`
>         ... which is depended on by `qga v0.1.0
> (/volatile/rustcargo/Rustup/Qemu/qemu.pwt/qga)`
>     perhaps a crate was updated and forgotten to be re-vendored?
>     As a reminder, you're using offline mode (--offline) which can
> sometimes cause surprising resolution failures, if this error is too
> confusing you may wish to retry without the offline flag.
>
> I think the most important part here is to get the general APIs,
> presented to general Rust code in Qemu, right.  So I wanted to review
> those via the output from rustdoc.
>

You can start by reading `cargo doc -p common --open`. The generated code
needs some environment variables set, so `cargo doc -p qga` will fail
unless you set the environment variable

MESON_BUILD_ROOT=`pwd` cargo doc -p qga --open --document-private-items

works, but the QAPI types aren't documented, so this is a bit useless at
this point. I wonder if I could put the schema doc, hmm...

> I tried commenting out the `replace-with` in .cargo/config.toml
> but evidently the systme isn't intended to be used that way.
>
> Ian.
>
>

-- 
Marc-André Lureau

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