Metadata V16: Features to include in V16

[lexnv]

Raising this issue to discuss about the features that are needed by the community in the next metadata version.

These features will be initially exposed under a metadata unstable versioning (u32::max), that will stabilize into v16.

I've compiled a possibly incomplete list of requested features that we may want to add to v16:

Requested features V16

Beta Give feedback

1. Metadata V16: Enrich metadata with associated types of config traits #4519
   I5-enhancement T1-FRAME +2
   
2. Extend metadata with deprecation #4098
   I5-enhancement T1-FRAME T13-deprecation +3
   
3. Encode required origin for extrinsics in metadata #349
   I5-enhancement T1-FRAME +2
   
4. Subscribe-able runtime apis #3594
   T0-node T3-RPC_API T4-runtime_API +3
5. [FRAME] pallet::dynamic_parameter attribute #3238
   +0
   
6. Metadata V16: Return multiple signed extensions by version #5285
   I5-enhancement T1-FRAME +2
7. Fix metadata naming around migration from SignedExtension to TransactionExtension #5347
   +0
8. Metadata V16: Introduce a Core_hash runtime API for hashing extrinsics #5468
   I5-enhancement T1-FRAME +2
   
9. Metadata V16: Have a vec of supported extrinsic versions #5980
   +0

cc @jsdw @niklasad1 @bkchr @paritytech/subxt-team @xlc @josepot

[bkchr]

polkadot-fellows/RFCs#99 with we would need to change the metadata to return multiple sets of transaction/signed extensions indexed by the version.

[josepot]

IMO an absolute must have of metadata v16 is a dedicated top-level entry named "hasher" (right after the "extrinsic" entry for instance, or at least at the same level), which should have 2 different properties:

• "name": the name of the hashing function
• "runtimeApi": a path to a runtime-api which just implements the hasher (E.g: Core_hash)

[Polkadot-Forum]

This issue has been mentioned on Polkadot Forum. There might be relevant details there:

https://forum.polkadot.network/t/metadata-v16-updates/9557/1

[Polkadot-Forum]

This issue has been mentioned on Polkadot Forum. There might be relevant details there:

https://forum.polkadot.network/t/metadata-v16-updates/9557/7