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migrate_from_blend moves a Blend V2 position to XOXNO in one transaction. The controller repays Blend debt, withdraws collateral and non-collateral supply, deposits the withdrawn assets as XOXNO collateral, and runs a final health check before persisting state.

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Entrypoint

migrate_from_blend(
    caller: Address,
    account_id: u64,                    // 0 creates a new account
    spoke_id: u32,
    hub_id: u32,
    blend_pool: Address,                // must be governance-approved
    collateral_assets: Vec<Address>,    // WithdrawCollateral, sweep-all
    supply_assets: Vec<Address>,        // Withdraw (non-collateral supply), sweep-all
    debt_caps: Vec<(Address, i128)>,    // (debt_asset, max_repay_cap)
) -> u64
ParameterSemantics
callerMust authorize the call. Owns the Blend position and the resulting XOXNO account.
account_id0 creates a fresh account; non-zero merges into an existing account owned by caller.
blend_poolTarget Blend pool. Must pass is_blend_pool_approved or the call reverts with #42 BlendPoolNotApproved.
collateral_assetsBlend collateral tokens to withdraw. Each uses WithdrawCollateral with i128::MAX internally.
supply_assetsBlend non-collateral supply to withdraw. Each uses Withdraw with i128::MAX. Deposited as XOXNO collateral.
debt_capsPer debt asset, the maximum the controller may borrow to repay Blend. Must be ≥ actual Blend debt.
At least one of {collateral_assets, supply_assets, debt_caps} must be non-empty.

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Atomic flow

The entire flow runs inside one controller call. Any revert rolls back all Blend and XOXNO state changes.

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Debt sourcing

Migration does not use the flash-loan receiver pattern. It uses an internal zero-fee strategy borrow:
Mechanismflash_loanMigration borrow
Entrypointcontroller.flash_loanopen_migration_borrow inside migrate_from_blend
Pool callpool.flash_loan → receiver callbackpool.create_strategy
FeeConfigured bps0
Debt outcomeRepaid in same callbackPermanent debt on the migrated account
Receiver contractRequiredNone
Solvency checkAt callback endAt strategy_finalize

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Refund reconciliation

debt_caps are upper bounds, not exact debt amounts. When Blend repays less than the cap, Blend refunds the surplus to the controller. reconcile_debt_refunds detects the refund via balance delta and calls repay_debt_from_controller. The migrated XOXNO debt equals the actual Blend debt, not the cap.

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Looped positions

When the same token is both collateral and debt (for example USDC collateral plus USDC debt), the controller uses a two-phase submit:
  1. Phase 1 — repay debt with an isolated balance snapshot so refunds do not alias with withdrawals.
  2. Phase 2 — withdraw collateral and supply with a fresh snapshot.
The same asset may appear in both collateral_assets and debt_caps. Duplicate debt entries in debt_caps revert with #AssetsAreTheSame.

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Blend request types

RequestConstantAmountPurpose
RepayREQ_REPAY = 5cap from debt_capsClear Blend debt
WithdrawCollateralREQ_WITHDRAW_COLLATERAL = 3i128::MAXSweep all collateral
WithdrawREQ_WITHDRAW = 1i128::MAXSweep non-collateral supply
Non-collateral Blend supply becomes collateral on XOXNO. XOXNO has no non-collateral supply concept.

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Authorization

LegWho authorizes
migrate_from_blendcaller.require_auth()
Blend submit(from=caller)Caller in the transaction auth tree (per phase)
transfer(controller → blend_pool, cap)Controller authorize_as_current_contract before repay submit

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Reentry guard

guarded_submit sets FlashLoanOngoing during Blend calls. Mutating controller entrypoints reject reentry while the guard is set (#400 FlashLoanOngoing).

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Governance

Blend pools are allow-listed through governance: 
# Schedule via governance (production):
propose_approve_blend_pool(proposer, blend_pool_address, salt)
# → execute after timelock
Approved pools are listed in configs/blend_pools.json. Query approval with is_blend_pool_approved(blend_pool).

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Events

BlendMigrationEvent {
    topics: ["strategy", "blend_migration"],
    account_id,
    blend_pool,
    collateral_count,
    supply_count,
    debt_count,
}

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Failure modes

ConditionError
Empty collateral_assets, supply_assets, and debt_caps#InvalidPayments
Unapproved blend_pool#42 BlendPoolNotApproved
Duplicate debt asset in debt_caps#AssetsAreTheSame
debt_cap below actual Blend debtBlend health check revert (atomic rollback)
End state fails health / LTV / min collateral#InsufficientCollateral at finalize
Caller does not own target accountOwnership mismatch

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Example invoke

stellar contract invoke --id <controller> --network <network> \
  --source <user> \
  -- migrate_from_blend \
  --caller <user> \
  --account-id 0 \
  --spoke-id 1 \
  --hub-id 1 \
  --blend-pool <approved_blend_pool> \
  --collateral-assets '[<XLM>]' \
  --supply-assets '[]' \
  --debt-caps '[["<USDC>", "1000000000"]]'
Set each debt_cap to at least the actual Blend debt for that asset. Use get_account_positions and Blend views to size caps before invoking.

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Next

Strategies

Multiply, swap debt, swap collateral, and repay-with-collateral flows.

Flash loans

The flash-loan receiver pattern — distinct from migration’s zero-fee borrow.

Accounts and risk

Account model, health factor, and spoke constraints after migration.

Controller ABI

Full migrate_from_blend signature and related admin entrypoints.