[Pkg-rust-maintainers] Bug#1016808: Bug#1016808: debcargo does not handle extra features for dev-dependencies declared in the features section.

[Fabian Grünbichler]

On August 7, 2022 9:01 pm, Peter Michael Green wrote:
> Package: debcargo
> Version: 2.5.0-3
> 
> Alexander Kjäll was working on packaging wl-clipboard-rs when he ran 
> into an autopkgtest failure.
>> debian cargo wrapper: options, profiles, parallel: ['parallel=4'] [] ['-j4']
>> debian cargo wrapper: rust_type, gnu_type: x86_64-unknown-linux-gnu, x86_64-linux-gnu
>> debian cargo wrapper: linking /usr/share/cargo/registry/* into /tmp/tmp.Zo0aVr3cJs/registry/
>> debian cargo wrapper: options, profiles, parallel: ['parallel=4'] [] ['-j4']
>> debian cargo wrapper: rust_type, gnu_type: x86_64-unknown-linux-gnu, x86_64-linux-gnu
>> debian cargo wrapper: running subprocess (['env', 'RUST_BACKTRACE=1', '/usr/bin/cargo', '-Zavoid-dev-deps', 'test', '--verbose', '--verbose', '-j4', '--target', 'x86_64-unknown-linux-gnu', '--all-targets', '--no-default-features', '--features', 'native_lib'],) {}
>> error: no matching package named `parking_lot` found
>> location searched: registry `crates-io`
>> required by package `wayland-server v0.29.4`
>>      ... which satisfies dependency `wayland-server = "^0.29.4"` of package `wl-clipboard-rs v0.6.0 (/usr/share/cargo/registry/wl-clipboard-rs-0.6.0)`
> 
> Investigating showed that Cargo.toml contains the following
> 
>> [dev-dependencies.wayland-server]
>> version = "0.29.4"
>>
>> [features]
>> dlopen = ["native_lib", "wayland-client/dlopen", "wayland-server/dlopen"]
>> native_lib = ["wayland-client/use_system_lib", 
>> "wayland-server/use_system_lib"]
> If I am reading this correctly this means that when running tests with 
> the "native_lib" feature enabled, the "use_system_lib" feature of the 
> wayland-server package will be enabled.
> 
> However debcargo does not generate a test dependency on 
> librust-wayland-server+use-system-lib-dev
> 
> I believe this is the result of the error Alexander encountered (and I 
> reproduced)
> 
> The packaging for wl-clipboard-rs ia available in the 
> WIP-wl-clipboard-rs branch of debcargo-conf.
> Package: debcargo
> Version: 2.5.0-3
> 
> Alexander Kjäll was working on packaging wl-clipboard-rs when he ran into an
> autopkgtest failure.
> 
>     debian cargo wrapper: options, profiles, parallel: ['parallel=4'] [] ['-j4']
>     debian cargo wrapper: rust_type, gnu_type: x86_64-unknown-linux-gnu, x86_64-linux-gnu
>     debian cargo wrapper: linking /usr/share/cargo/registry/* into /tmp/tmp.Zo0aVr3cJs/registry/
>     debian cargo wrapper: options, profiles, parallel: ['parallel=4'] [] ['-j4']
>     debian cargo wrapper: rust_type, gnu_type: x86_64-unknown-linux-gnu, x86_64-linux-gnu
>     debian cargo wrapper: running subprocess (['env', 'RUST_BACKTRACE=1', '/usr/bin/cargo', '-Zavoid-dev-deps', 'test', '--verbose', '--verbose', '-j4', '--target', 'x86_64-unknown-linux-gnu', '--all-targets', '--no-default-features', '--features', 'native_lib'],) {}
>     error: no matching package named `parking_lot` found
>     location searched: registry `crates-io`
>     required by package `wayland-server v0.29.4`
>         ... which satisfies dependency `wayland-server = "^0.29.4"` of package `wl-clipboard-rs v0.6.0 (/usr/share/cargo/registry/wl-clipboard-rs-0.6.0)`
> 
> Investigating showed that Cargo.toml contains the following
> 
>     [dev-dependencies.wayland-server]
>     version = "0.29.4"
> 
>     [features]
>     dlopen = ["native_lib", "wayland-client/dlopen", "wayland-server/dlopen"]
>     native_lib = ["wayland-client/use_system_lib", "wayland-server/
>     use_system_lib"]
> 
> If I am reading this correctly this means that when running tests with the
> "native_lib" feature enabled, the "use_system_lib" feature of the
> wayland-server package will be enabled.
> 
> However debcargo does not generate a test dependency on
> librust-wayland-server+use-system-lib-dev
> 
> I believe this is the result of the error Alexander encountered (and I
> reproduced)
> 
> The packaging for wl-clipboard-rs ia available in the WIP-wl-clipboard-rs
> branch of debcargo-conf.

just to add some extra info:

such a feature -> dev-dep relationship is currently intentionally 
dropped when resolving features and dependencies[0]. it probably makes 
sense to only do that for "regular" resolution, and keep them for 
"autopkgtest" resolution, like you proposed - either by extending[1] the 
relevant code[1,2] to keep track of them separately, or by introducing a 
parameter to control skipping them. given that there are currently only 
two call sites and both might benefit from having the extra info 
available, extending might be better.

as a workaround, setting "test_depends" in debcargo.toml manually should 
work (although it is rather cumbersome for all the obvious reasons).

0: https://salsa.debian.org/rust-team/debcargo/-/issues/37 (and the 
commit closing it)
1: https://salsa.debian.org/rust-team/debcargo/-/blob/master/src/crates.rs#L46
2: https://salsa.debian.org/rust-team/debcargo/-/blob/master/src/crates.rs#L380