Vision: Improve Developer Experience with better Config Traits

[shawntabrizi]

There are common types defined within the config of different pallets, such as:

type Event: From<Event<Self>> + IsType<<Self as frame_system::Config>::Event>;

type Call: IsType<<Self as frame_system::Config>::Call>
	+ Dispatchable<Origin = Self::Origin, PostInfo = PostDispatchInfo>
	+ GetDispatchInfo
	+ FullCodec
	+ From<frame_system::Call<Self>>;

type Origin: From<RawOrigin<Self::AccountId, I>>;

etc...

All of these types have some complicated traits which are expected from the construct_runtime! macro, and often the user struggles to define all those types when doing runtime development.

We could simply wrap all of these traits in a simple to understand trait exposed in frame_support like:

trait FrameCall: IsType<<Self as frame_system::Config>::Call>
	+ Dispatchable<Origin = Self::Origin, PostInfo = PostDispatchInfo>
	+ GetDispatchInfo
	+ FullCodec
	+ From<frame_system::Call<Self>>
{}

Then simply define:

type Call: frame_support::FrameCall

or something like that.

[dharjeezy]

Hello @shawntabrizi is this particular issue available for pick up?
I am willing to pick it up

[bkchr]

All of these types have some complicated traits which are expected from the construct_runtime! macro

That is not correct. You add the traits bounds that you are require for a certain type in your pallet. The runtime is only required to provide types that implement the given traits.

[shawntabrizi]

@bkchr I think you are saying what I am saying?

For example, we know construct_runtime! implements a bunch of traits, like From/Into for inner and outer events, inner and outer origin, inner and outer Call type.

We also know that something like the Call type must satisfy a bunch of traits which are expected in other parts of the codebase, like Dispatchable or GetDispatchInfo. The whole thing I am saying is we can take all these assumptions about common types in the FRAME runtime and place them under a single simple trait.

Or what am I misunderstanding?

[bkchr]

That is right what you are saying. I just wanted to highlight that some pallets may only require that a Call implements Encode. Then you also just need to bound for Encode.

[kianenigma]

Related to paritytech/substrate#13454