Add chain exts for direct recycle/burn from ink! smart contracts #2564
Description
Is your feature request related to a problem? Please describe.
ink! smart contracts on subtensor that need to recycle or burn alpha stake must currently transfer funds to a designated external wallet, which then performs the operation. This intermediary wallet holds controllable funds, creating custodial risk regardless of intent. There is no way for a WASM smart contract to call recycle or burn directly via the chain extension interface.
Describe the solution you'd like
Add 4 new chain extension functions allowing ink! contracts to invoke recycle/burn directly
| Name | Description |
|---|---|
RecycleAlphaV1 |
Recycle alpha stake from the contract |
BurnAlphaV1 |
Burn alpha stake from the contract |
AddStakeRecycleV1 |
Atomically add TAO stake then recycle alpha |
AddStakeBurnV1 |
Atomically add TAO stake then burn alpha |
The current AddStakeV1 chain extension only returns a success/error code, not the resulting alpha amount. While a contract could work around this by calling AddStakeV1 followed by RecycleAlphaV1(MAX), this recycles all alpha the contract holds on that subnet — not just the alpha from that specific stake. This is fine for simple contracts, but may break down for contracts that hold alpha for multiple purposes on the same subnet.
The AddStakeRecycleV1 and AddStakeBurnV1 functions handle this atomically in a single call, recycling/burning only the alpha produced by that specific stake. This provides the robustness needed for a general-purpose chain extension interface.
Describe alternatives you've considered
The current approach: transferring collected fees to a designated wallet that performs recycle/burn externally. This works functionally but requires trust in the wallet operator and introduces a single point of failure. It also prevents fully autonomous contract operation.
Additional context
Primary use case: smart contracts collecting subnet fees that need to autonomously recycle those fees back into the subnet without human intervention or off-chain infrastructure.