feat: add new DID runtime APIs to aid with DID deletion

[ntn-x2]

Fixes https://github.com/KILTprotocol/ticket/issues/3742.

The PR introduces two new runtime APIs: one that returns an enum of "linked resources", which some clients might find useful to understand why a DID deletion failed, and one that returns a list of RuntimeCalls, that could be extended with a did.delete() call, put together into a utility.batch*, and submitted to the chain, and be sure the DID deletion will work as expected (as long as all the DID origin requirements are met).

[rflechtner]

Seems reasonable! The enums can serve as the missing error cases to show to users via a UI to help users identify which clean up steps they need to perform. And for the transactions I would assume the client just needs logic to batch them in a DID-origin transaction, which the sdk already has. Did you try this out?

[rflechtner]

that's because we have the two instances of the linking pallet?

[ntn-x2]

Yes, exactly.

[ntn-x2]

And for the transactions I would assume the client just needs logic to batch them in a DID-origin transaction, which the sdk already has. Did you try this out?

Correct, as long as the batch also includes the did.delete tx at the end as well, which is of course not included in the result of this runtime call. I did test this locally with a peregrine-based chopsticks instance, but notice this won't work with the standalone runtime that the SDK uses for integration tests: or rather, the runtime call will always return [] which means the delete operation will never fail.

As for testing, I modified locally the Web3name integration test should be possible to remove a w3n by the owner did with the following, which worked as expected:

const deletionCalls: [SubmittableExtrinsic] =
      await api.call.did.linkedResourcesDeletionCalls(
        Did.toChain(w3nCreator.uri)
      )

    const tx = api.tx.utility.batchAll([
      // Old call
      // api.tx.web3Names.releaseByOwner(),
      ...deletionCalls,
      api.tx.did.delete(0),
    ])
    const authorizedTx = await Did.authorizeTx(
      w3nCreator.uri,
      tx,
      w3nCreatorKey.getSignCallback(w3nCreator),
      paymentAccount.address
    )
    await submitTx(authorizedTx, paymentAccount)

Commeting out the ...deletionCalls and only leaving api.tx.did.delete(0) fails with a CannotDelete error, which is also expected.

I modified the type definitions locally with the following:

const tmpCalls = Object.assign(Object.assign({}, batchedDidApiCalls), { linked_resources: {
        description: '',
        params: [
            {
                name: 'did',
                type: 'AccountId32',
            },
        ],
        type: 'Vec<LinkedDidResource>',
    }, linked_resources_deletion_calls: {
        description: '',
        params: [
            {
                name: 'did',
                type: 'AccountId32',
            },
        ],
        type: 'Vec<RuntimeCall>',
    }});

and properly defined the LinkedDidResource type. I will work on a PR that adds these to the repo.

EDIT: PR for the types repo: https://github.com/KILTprotocol/types-augment/pull/26.