[pallet-xcm] Adjust benchmarks (teleport_assets/reserve_transfer_assets) not relying on ED

[bkontur]

Problem

During the bumping of the polkadot-fellows repository to polkadot-sdk@1.6.0, I encountered a situation where the benchmarks teleport_assets and reserve_transfer_assets in AssetHubKusama started to fail. This issue arose due to a decreased ED balance for AssetHubs introduced here, and also because of a missing CI pipeline to check the benchmarks, which went unnoticed.

These benchmarks expect the caller to have enough:

1. balance to transfer (BTT)
2. balance for paying delivery (BFPD).

So the initial balance was calculated as ED * 100, which seems reasonable:

const ED_MULTIPLIER: u32 = 100;
let balance = existential_deposit.saturating_mul(ED_MULTIPLIER.into());`

The problem arises when the price for delivery is 100 times higher than the existential deposit. In other words, when ED * 100 does not cover BTT + BFPD.

I check AHR/AHW/AHK/AHP and this problem has only AssetHubKusama

ED: 3333333
calculated price to parent delivery:  1031666634  (from xcm logs from the benchmark)
---

3333333 * 100 - BTT(3333333) - BFPD(1031666634) = −701666667

which results in the error;

2024-02-23 09:19:42 Unable to charge fee with error Module(ModuleError { index: 31, error: [17, 0, 0, 0], message: Some("FeesNotMet") })
Error: Input("Benchmark pallet_xcm::reserve_transfer_assets failed: FeesNotMet")
     

Solution

The benchmarks teleport_assets and reserve_transfer_assets were fixed by removing ED * 100 and replacing it with DeliveryHelper logic, which calculates the (almost real) price for delivery and sets it along with the existential deposit as the initial balance for the account used in the benchmark.

TODO

• patch for 1.6 - [pallet-xcm] Adjust benchmarks (teleport_assets/reserve_transfer_assets) not relying on ED (patch for 1.6) #3466
• patch for 1.7 - [pallet-xcm] Adjust benchmarks (teleport_assets/reserve_transfer_assets) not relying on ED (patch for 1.7.0) #3465
• patch for 1.8 - cherry-picked directly to the release-crates-io-v1.8.0

[franciscoaguirre]

Looks good