[Pkg-rust-maintainers] Bug#1000942: rust-zbus-macros - autopkgtest failure, makes reverse dependencies FTBFS.

[peter green]

Package: rust-zbus-macros
Version: 1.0.0-3
Severity: serious
x-debbugs-cc: debian at nilux.be

The rust-zbus-macros autopkgtest is failing:


> error[E0432]: unresolved import `zbus`
>   --> /tmp/tmp.2o6G5gYnNc/registry/zbus-1.0.0/src/object_server.rs:54:1
>    |
> 54 | #[dbus_interface(name = "org.freedesktop.DBus.Introspectable")]
>    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ no `Type` in the root
>    |
>    = note: this error originates in the attribute macro `dbus_interface` (in Nightly builds, run with -Z macro-backtrace for more info)

I also did test-builds of the reverse dependencies rust-zbus and rust-libslirp (note: I had to manually
build mio-0.6 to test rust-libslirp as it is currently sitting in new) and they failed with similar
errors, so this is not just an autopkgtest issue.

I don't know for certain but I assume that just relaxing the dependency was
not enough to make it work correctly with the new version of rust-proc-macro-crate.

I also tried doing a test rebuild of rust-libslirp (which afaict is the only binary crate that depends on

I took a look in the upstream VCS and found a patch for rust-proc-macro-crate 1 and tried applying it, unfortunately
it dependeded on a bunch of other upstream commits. Updating to the latest stable upstream helped a bit with getting
the patches to apply and I was able to get a succesful build of rust-zbus-macros 1.9.2 with
a pile of upstream patches.

Unfortunately when running it's autopkgtests I ran into another issue. It seems that rust-zbus has a strictly versioned
dependency on the identical version rust-zbus-macros and rust-zbus 1.9.2 brings several new dependencies.

dpkg-checkbuilddeps: error: Unmet build dependencies: librust-async-io-1+default-dev (>= 1.3.1-~~) librust-nb-connect-1+default-dev (>= 1.0.2-~~) librust-polling-2+default-dev (>= 2.0.2-~~)

That is pretty much as far as i'm prepared to go. I have pushed my attempts to https://salsa.debian.org/rust-team/debcargo-conf/-/tree/zbus-1.9.2
if anyone else wants to pick them up.

The other option would be to prepare/upload a rust-proc-macro-crate-0.1 package and then
revert the dependency in rust-zbus-macros. I may do that if noone comes up with a better
solution.