Use trait object for progress in PrepareFetch::fetch_only

[NobodyXu]

No description provided.

[NobodyXu]

It turns out that using DynNestedProgress as a trait object and then use DynNestedProgressToNestedProgress doesn't work:

error[E0277]: the trait bound `dyn gix_features::progress::DynNestedProgress: gix_features::progress::Nest
edProgress` is not satisfied
   --> gix/src/clone/fetch/mod.rs:146:14
    |
146 |             .receive(DynNestedProgressToNestedProgress(progress), should_interrupt)
    |              ^^^^^^^ the trait `gix_features::progress::NestedProgress` is not implemented for `dyn 
gix_features::progress::DynNestedProgress`
    |
    = help: the following other types implement trait `gix_features::progress::NestedProgress`:              gix_features::progress::prodash::tree::Item
              gix_features::progress::Discard
              gix_features::progress::Either<L, R>
              gix_features::progress::DoOrDiscard<T>
              gix_features::progress::ThroughputOnDrop<T>
              gix_features::progress::BoxedDynNestedProgress
              gix_features::progress::DynNestedProgressToNestedProgress<T>
              &'a mut T
    = note: required for `&mut dyn gix_features::progress::DynNestedProgress` to implement `gix_features::
progress::NestedProgress`
    = note: required for `&mut dyn gix_features::progress::DynNestedProgress` to implement `gix_features::
progress::DynNestedProgress`
    = note: 1 redundant requirement hidden
    = note: required for `DynNestedProgressToNestedProgress<&mut dyn DynNestedProgress>` to implement `gix
_features::progress::NestedProgress`
    = note: the full type name has been written to '/Users/nobodyxu/Dev/gitoxide/target/debug/deps/gix-c1b
f5d15fa5fd661.long-type-8934911478669783998.txt'

For more information about this error, try `rustc --explain E0277`.
error: could not compile `gix` (lib) due to previous error

Content of /Users/nobodyxu/Dev/gitoxide/target/debug/deps/gix-c1b f5d15fa5fd661.long-type-8934911478669783998.txt:

gix_features::progress::DynNestedProgressToNestedProgress<&mut dyn gix_features::progress::DynNestedProgress>

[NobodyXu]

I've already opened Byron/prodash#24 for fixing use of Progress and Count as trait object, but I still haven't figured out how to fix DynNestedProgressToProgress.

[Byron]

Is DynNestedProgressToProgress actually needed anywhere? I thought that in all places, one should be able to use &mut dyn DynNestedProgress. Maybe that can be an avenue towards solving the issue, by avoidance. Disclaimer: I do definitely speak out of ignorance here.

[NobodyXu]

It's used in gix::remote::fetch::Prepare::receive since it expects NestedProgress.

I can actually workaround this issue by creating a receive_inner that takes DynNestedProgress instead.

[Byron]

Great to hear that this wasn't a blocker! Thanks again for the initiative!

[Byron]

That's nice! Thanks for introducing this feature!