Nomination Transfer

[Dinonard]

Nomination Transfer

Summary

A new functionality is introduced for the dapps-staking pallet - nomination transfer. The idea is to allow stakers to transfer their nomination from contract_A to contract_B while bypassing the unbonding period. This is great for stakers who have already staked on some contract but found another one they would like to nominate instead. Prior to nomination_transfer, they would have to wait first for the unbonding period to complete, not earning any staking rewards, before being able to re-stake their rewards.

Requirements (useful for UI)

There are certain requirements that must be met in order for nomination transfer to work:

• there must be available nomination transfer charges
  • this requires storage read and removal of old cooldown blocks before checking
• both contracts must be in Registered state
• origin contract must differ from the target contract
• rest of the requirements are same as for bond_and_stake and unbond_and_unstake
  • only difference is that there's no check for unbonding_period since it's bypassed here
  • it is possible that if staker isn't already staking on target contract, there are no staking slots left
  • same goes for the amount being transferred - it might be insufficient if this is first stake on the target contract
  • EraStake values will be produced both for origin and target contract and will be checked against MaxEraStakeValues
  • if nomination transfer amount will take staker below minimum staking amount on the origin contract, staker will be fully unstaked from the origin contract and entire amount will be transferred to the target contract

TODO

• [x] run benchmarks & update weights in the pallet
• [x] update precompiles interface & test
• [x] prepare demo video for the team
• [x] discuss how to handle cooldowns (REMOVED)
• [x] create a backlog item for re-staking unbonding chunks?
• [ ] re-run benchmarks prior to merge

Check list

• [ ] contains breaking changes
• [x] adds new feature
• [x] modifies existing feature (bug fix or improvements)
• [ ] relies on other tasks
• [ ] documentation changes
• [x] tests and/or benchmarks are included
• [ ] changed API client type definition or chain metadata

[Maar-io]

My only comment is usability of the precompile changes to support withdraw_from_unregistered and nomination_transfer. Maybe Astar portal will have use of these but I do not see why would evm smart contract use these calls.

[Dinonard]

@Maar-io for the withdraw_from_unregistered, if contract is staking on another contract that gets unregistered, they cannot get their staked tokens out otherwise.

For nomination_transfer, I added it for consistency.