[Libguestfs] Cargo edition problem with Debian 11

Richard W.M. Jones rjones at redhat.com
Fri Jan 13 18:00:07 UTC 2023 

On Fri, Jan 13, 2023 at 10:52:33AM -0700, alan somers wrote:
> There actually isn't any real problem to fix; it's purely a CI problem.
> 
> Our Cargo.toml file (and transitively, our dependencies' Cargo.toml
> files) specify that we need predicates-tree and predicates-core.
> Unless instructed otherwise, Cargo will attempt to fetch the latest
> compatible version.  However, the latest compatible versions don't
> build with the older toolchain.  That why my PR adds a Cargo.lock file
> which locks predicates-tree and predicates-core to exact versions that
> are known to be compatible with Rust 1.48.0.  That fixes the build in
> CI.
> 
> But the thing is, a Rust library crate never ships a Cargo.lock file.
> Even if it did, Cargo would ignore it when building an application
> that depends on that library.  So if any of nbdkit's consumers want to
> build with Rust 1.48.0, they'll have to do the same Cargo.lock dance
> that I did.  We don't need to make any changes to facilitate that.
> Furthermore, nbdkit's consumers probably _won't_ need to do this at
> all, because predicates-tree and predicates-core are merely
> dev-dependencies of nbdkit.  Our consumers won't necessarily need to
> fetch them at all.
> 
> Does that make sense?  And knowing this, would you prefer to skip the
> Rust build in those environments, or do the Cargo.lock thing?  I'd be
> ok with either.

Understood.  So let's skip the test on the platform that fails.

I'll push something to PR#19 in a few mins.

Rich.


> On Fri, Jan 13, 2023 at 10:43 AM Richard W.M. Jones <rjones at redhat.com> wrote:
> >
> > On Fri, Jan 13, 2023 at 09:17:29AM -0700, alan somers wrote:
> > > Oh, I misread your initial mail.  I saw "Debian" in the subject line
> > > and assumed you were talking about packaging.  But you weren't.  This
> > > is happening in CI for every platform.
> > >
> > > There's a straightforward way to fix the problem for Cirrus CI, the
> > > one that runs after we mirror to Github.  But it requires an extra
> > > step, and I'm not sure how to configure that for the .gitlab CI stuff.
> > > I'll submit a partial PR and ask for help with the gitlab CI part.
> > >
> > > You aren't using gitlab CI to build release artifacts, are you?
> >
> > We're using a rather complicated scheme called libvirt-ci which
> > I don't fully understand.  (Adding Eric to CC)
> >
> > Re your merge request here:
> >
> > https://github.com/libguestfs/nbdkit/pull/19
> >
> > I believe we could do this more easily for debian-11 simply by adding
> >
> >    RUST: skip
> >
> > to the relevant section of ci/manifest.yml.
> >
> > However my main thing is could we actually fix it instead of covering
> > up the problem in CI?
> >
> > Rich.
> >
> > > On Fri, Jan 13, 2023 at 8:57 AM Richard W.M. Jones <rjones at redhat.com> wrote:
> > > >
> > > > On Fri, Jan 13, 2023 at 08:35:08AM -0700, alan somers wrote:
> > > > > The nbdkit crate.  Why does Debian need a package for it?
> > > >
> > > > I'm not sure -- do they have one?  I can't seem to find it.
> > > >
> > > > Rich.
> > > >
> > > > > On Fri, Jan 13, 2023 at 8:30 AM Richard W.M. Jones <rjones at redhat.com> wrote:
> > > > > >
> > > > > > On Fri, Jan 13, 2023 at 08:25:28AM -0700, alan somers wrote:
> > > > > > > IMHO this is a design bug in Debian.  Sure, they need to create
> > > > > > > packages for any Rust crate that needs to install executable or .so
> > > > > > > files.  But crates like nbdkit don't install anything.  They're only
> > > > > > > used to build other Rust crates, and only used at compile time.  They
> > > > > > > can simply be fetched during the package building process.  I really
> > > > > > > don't know what Debian is doing by packaging this crate.  Is it
> > > > > > > actually trying to install the ramdisk example?
> > > > > >
> > > > > > I'm not sure I understand - which crate?
> > > > > >
> > > > > > Rich.
> > > > > >
> > > > > > > On Fri, Jan 13, 2023 at 7:27 AM Richard W.M. Jones <rjones at redhat.com> wrote:
> > > > > > > >
> > > > > > > > On Fri, Jan 13, 2023 at 07:17:14AM -0700, alan somers wrote:
> > > > > > > > > I think we should downgrade predicates-tree to 1.0.5 or older.  I can
> > > > > > > > > submit a PR for that.  What does "rustc --version" show you?
> > > > > > > >
> > > > > > > > Unfortunately our configure script doesn't collect that information
> > > > > > > > (it should do! - I'll fix that in a moment).
> > > > > > > >
> > > > > > > > But based on it being Debian 11 ("bullseye") it's likely to be:
> > > > > > > >
> > > > > > > > https://packages.debian.org/bullseye/rustc
> > > > > > > > Package: rustc (1.48.0+dfsg1-2)
> > > > > > > >
> > > > > > > > Which is pretty ancient ...
> > > > > > > >
> > > > > > > > Rich.
> > > > > > > >
> > > > > > > > > On Fri, Jan 13, 2023 at 2:41 AM Richard W.M. Jones <rjones at redhat.com> wrote:
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > https://gitlab.com/nbdkit/nbdkit/-/jobs/3598390121
> > > > > > > > > >
> > > > > > > > > > ----------------------------------------------------------------------
> > > > > > > > > > cargo build --release --example ramdisk
> > > > > > > > > >  Downloading crates ...
> > > > > > > > > >   Downloaded float-cmp v0.9.0
> > > > > > > > > >   Downloaded downcast v0.11.0
> > > > > > > > > >   Downloaded mockall_derive v0.11.3
> > > > > > > > > >   Downloaded itertools v0.10.5
> > > > > > > > > >   Downloaded aho-corasick v0.7.20
> > > > > > > > > >   Downloaded predicates-tree v1.0.7
> > > > > > > > > > error: failed to parse manifest at `/root/.cargo/registry/src/github.com-1ecc6299db9ec823/predicates-tree-1.0.7/Cargo.toml`
> > > > > > > > > > Caused by:
> > > > > > > > > >   failed to parse the `edition` key
> > > > > > > > > > Caused by:
> > > > > > > > > >   this version of Cargo is older than the `2021` edition, and only supports `2015` and `2018` editions.
> > > > > > > > > > ----------------------------------------------------------------------
> > > > > > > > > >
> > > > > > > > > > nbdkit itself uses edition = 2018, but this seems to affects one of
> > > > > > > > > > the dependencies.
> > > > > > > > > >
> > > > > > > > > > I'm not sure how to solve this, but one ideas I had is in ./configure
> > > > > > > > > > to check if the cargo/rust we're trying to use doesn't support some
> > > > > > > > > > base edition (eg. latest edition supported < 2021) then we would
> > > > > > > > > > disable rust bindings.
> > > > > > > > > >
> > > > > > > > > > Unfortunately actually getting the latest supported edition seems
> > > > > > > > > > hard.  The best I could find is parsing this which doesn't seem ideal:
> > > > > > > > > >
> > > > > > > > > > $ rustc --help |& grep -- --edition
> > > > > > > > > >         --edition 2015|2018|2021|2024
> > > > > > > > > >
> > > > > > > > > > What do you think?
> > > > > > > > > >
> > > > > > > > > > Rich.
> > > > > > > > > >
> > > > > > > > > > --
> > > > > > > > > > Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
> > > > > > > > > > Read my programming and virtualization blog: http://rwmj.wordpress.com
> > > > > > > > > > libguestfs lets you edit virtual machines.  Supports shell scripting,
> > > > > > > > > > bindings from many languages.  http://libguestfs.org
> > > > > > > > > >
> > > > > > > >
> > > > > > > > --
> > > > > > > > Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
> > > > > > > > Read my programming and virtualization blog: http://rwmj.wordpress.com
> > > > > > > > Fedora Windows cross-compiler. Compile Windows programs, test, and
> > > > > > > > build Windows installers. Over 100 libraries supported.
> > > > > > > > http://fedoraproject.org/wiki/MinGW
> > > > > > > >
> > > > > >
> > > > > > --
> > > > > > Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
> > > > > > Read my programming and virtualization blog: http://rwmj.wordpress.com
> > > > > > Fedora Windows cross-compiler. Compile Windows programs, test, and
> > > > > > build Windows installers. Over 100 libraries supported.
> > > > > > http://fedoraproject.org/wiki/MinGW
> > > > > >
> > > >
> > > > --
> > > > Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
> > > > Read my programming and virtualization blog: http://rwmj.wordpress.com
> > > > nbdkit - Flexible, fast NBD server with plugins
> > > > https://gitlab.com/nbdkit/nbdkit
> > > >
> >
> > --
> > Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
> > Read my programming and virtualization blog: http://rwmj.wordpress.com
> > virt-builder quickly builds VMs from scratch
> > http://libguestfs.org/virt-builder.1.html
> >

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
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