Implement support for `Box<[T]>` and `Arc<[T]>`
Opened this issue · 3 comments
nazar-pc commented
Arc<[T]> is especially helpful in cases where something needs to be sent into a different thread, but cloning and double indirection are undesirable.
Right now both fail something like this:
error[E0277]: the trait bound `[subspace_core_primitives::pieces::PieceIndex]: parity_scale_codec::WrapperTypeDecode` is not satisfied
--> crates/subspace-networking/src/protocols/request_response/handlers/cached_piece_by_index.rs:28:24
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28 | pub cached_pieces: Box<[PieceIndex]>,
| ^^^^^^^^^^^^^^^^^ the trait `parity_scale_codec::WrapperTypeDecode` is not implemented for `[subspace_core_primitives::pieces::PieceIndex]`, which is required by `std::boxed::Box<[subspace_core_primitives::pieces::PieceIndex]>: parity_scale_codec::Decode`
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= help: the following other types implement trait `parity_scale_codec::WrapperTypeDecode`:
std::boxed::Box<T>
std::rc::Rc<T>
std::sync::Arc<T>
= note: required for `[subspace_core_primitives::pieces::PieceIndex]` to implement `parity_scale_codec::Decode`
= note: 1 redundant requirement hidden
= note: required for `std::boxed::Box<[subspace_core_primitives::pieces::PieceIndex]>` to implement `parity_scale_codec::Decode`
I'm not 100% sure, but suspect it is an upstream issue since downstream users will not be able to implement WrapperTypeDecode for Box<[T]> or Arc<[T]>.
teor2345 commented
Specifically, this will need an implementation of WrapperTypeDecode<Wrapped = Vec<T>> for these types, because Wrapped has to be Into<Arc<[T]>>. Since slices are unsized, they can’t implement Into.
We might as well also do Rc<[T]>.
chanderprakash20 commented
Hi @nazar-pc is your issue get resolved or not ?