Dynamic call indices for sudo and utility batch

[ascjones]

Currently the Sudo::sudo and Utility::batch dispatchables generate code which accepts statically constructed instances of the top level Call enum. This means that if there is a mismatch of pallet/dispatchable composition between the static metadata used to generate API, and the target node runtime, then the node will fail to decode the calls.

When making a Call directly, the API will use the metadata of the running node to prepend the pallet index and the call index. We should consider making this available when constructing these composite dispatchables.

Extracted from #309

[wischli]

Any update on this matter? I am trying to execute dynamic batch calls and assume it not to be working in 0.25.0 due to this issue?

[ascjones]

See the latest thinking in #716.

I think pure dynamic calls might be working, e.g. see the multisig example: https://github.com/paritytech/subxt/blob/master/examples/examples/dynamic_multisig.rs#L61.

Note if you are running e.g. one off scripts where you can guarantee the metadata is synced with the target node you can use the statically generated types e.g. https://github.com/ascjones/seeding/blob/main/src/main.rs#L47

[jsdw]

This is something that scale-encode aims to solve, once it's integrated into Subxt. I'm off until Jan though so unless somebody else picks that up, it'll happen next month :)

[jsdw]

This is resolved now on master (soon to be released as 0.28); the RuntimeCall types will now be encoded with the help of metadata and matched on variant names, not indexes, however nested they are.