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Unverified Commit d5053ac4 authored by Francisco Aguirre's avatar Francisco Aguirre Committed by GitHub
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Change `XcmDryRunApi::dry_run_extrinsic` to take a call instead (#4621)



Follow-up to the new `XcmDryRunApi` runtime API introduced in
https://github.com/paritytech/polkadot-sdk/pull/3872.

Taking an extrinsic means the frontend has to sign first to dry-run and
once again to submit.
This is bad UX which is solved by taking an `origin` and a `call`.
This also has the benefit of being able to dry-run as any account, since
it needs no signature.

This is a breaking change since I changed `dry_run_extrinsic` to
`dry_run_call`, however, this API is still only on testnets.
The crates are bumped accordingly.

As a part of this PR, I changed the name of the API from `XcmDryRunApi`
to just `DryRunApi`, since it can be used for general dry-running :)

Step towards https://github.com/paritytech/polkadot-sdk/issues/690.

Example of calling the API with PAPI, not the best code, just testing :)

```ts
// We just build a call, the arguments make it look very big though.
const call = localApi.tx.XcmPallet.transfer_assets({
  dest: XcmVersionedLocation.V4({ parents: 0, interior: XcmV4Junctions.X1(XcmV4Junction.Parachain(1000)) }),
  beneficiary: XcmVersionedLocation.V4({ parents: 0, interior: XcmV4Junctions.X1(XcmV4Junction.AccountId32({ network: undefined, id: Binary.fromBytes(encodeAccount(account.address)) })) }),
  weight_limit: XcmV3WeightLimit.Unlimited(),
  assets: XcmVersionedAssets.V4([{
    id: { parents: 0, interior: XcmV4Junctions.Here() },
    fun: XcmV3MultiassetFungibility.Fungible(1_000_000_000_000n) }
  ]),
  fee_asset_item: 0,
});
// We call the API passing in a signed origin 
const result = await localApi.apis.XcmDryRunApi.dry_run_call(
  WestendRuntimeOriginCaller.system(DispatchRawOrigin.Signed(account.address)),
  call.decodedCall
);
if (result.success && result.value.execution_result.success) {
  // We find the forwarded XCM we want. The first one going to AssetHub in this case.
  const xcmsToAssetHub = result.value.forwarded_xcms.find(([location, _]) => (
    location.type === "V4" &&
      location.value.parents === 0 &&
      location.value.interior.type === "X1"
      && location.value.interior.value.type === "Parachain"
      && location.value.interior.value.value === 1000
  ))!;

  // We can even find the delivery fees for that forwarded XCM.
  const deliveryFeesQuery = await localApi.apis.XcmPaymentApi.query_delivery_fees(xcmsToAssetHub[0], xcmsToAssetHub[1][0]);

  if (deliveryFeesQuery.success) {
    const amount = deliveryFeesQuery.value.type === "V4" && deliveryFeesQuery.value.value[0].fun.type === "Fungible" && deliveryFeesQuery.value.value[0].fun.value.valueOf() || 0n;
    // We store them in state somewhere.
    setDeliveryFees(formatAmount(BigInt(amount)));
  }
}
```

---------

Co-authored-by: default avatarBastian Köcher <[email protected]>
parent aa32faae
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