Module decimals 

One-shot migration that populates decimal snapshots for a pre-existing PSM deployment.

Purpose: chains that approved external assets before the multi-decimal upgrade have entries in ExternalAssets but no ExternalDecimals snapshots, and no InternalDecimals either. Mint and redeem both require these snapshots and will fail closed (Error::DecimalsMismatch / Error::Unexpected) until they are populated. This migration reads live metadata and writes the snapshots.

Out-of-range assets are handled gracefully: if an existing asset’s decimals differ from the internal asset’s decimals by more than MAX_DECIMALS_DIFF, the migration still writes its decimals snapshot but flips its circuit breaker to CircuitBreakerLevel::AllDisabled. The chain keeps upgrading; governance can remove or re-enable the asset later once the off-chain situation is resolved. The try-runtime post-upgrade hook verifies this invariant — any out-of-range asset must end up disabled.

Safe to run multiple times — already-populated snapshots are not overwritten.

Usage

pub type Migrations = (
    pallet_psm::migrations::decimals::PopulateDecimals<Runtime>,
    // ... other migrations
);

Structs

InnerPopulateDecimals

Version-unchecked migration logic. Exposed only for use by PopulateDecimals.

Type Aliases

PopulateDecimals

Version-gated v1 -> v2 migration that fills in decimal snapshots for all pre-existing external assets and the internal asset, and bumps the pallet on-chain storage version from 1 to 2.