# Schema: Polkadot SDK PRDoc Schema (prdoc) v1.0.0
# See doc at https://raw.githubusercontent.com/paritytech/polkadot-sdk/master/prdoc/schema_user.json

title: "migrations: prevent accidentally using inner unversioned migration instead of `VersionedMigration`"

doc:
  - audience: Runtime Dev
    description: |
      Currently, it is possible to accidentally use inner unversioned migration instead of `VersionedMigration` 
      since both implement `OnRuntimeUpgrade`. With this change, we make it clear that `Inner` is not intended 
      to be used directly. It is achieved by bounding `Inner` to new trait `UncheckedOnRuntimeUpgrade`, which 
      has the same interface as `OnRuntimeUpgrade`, but can not be used directly for runtime upgrade migrations.
      
      This change will break all existing migrations passed to `VersionedMigration`. Developers should simply change 
      those migrations to implement `UncheckedOnRuntimeUpgrade` instead of `OnRuntimeUpgrade`.

      Example:

      ```
      --- a/path/to/migration.rs
      +++ b/path/to/migration.rs
      @@ -1,7 +1,7 @@
      -impl<T: Config> OnRuntimeUpgrade for MigrateVNToVM<T> {
      +impl<T: Config> UncheckedOnRuntimeUpgrade for MigrateVNToVM<T> {
          fn on_runtime_upgrade() -> Weight {
              // Migration logic here
              // Adjust the migration logic if necessary to align with the expectations
              // of new `UncheckedOnRuntimeUpgrade` trait.
              0
          }
      }
      ```

crates:
  - name: "pallet-example-single-block-migrations"
    bump: "major"
  - name: "pallet-xcm"
    bump: "major"
  - name: "pallet-grandpa"
    bump: "major"
  - name: "pallet-identity"
    bump: "major"
  - name: "pallet-nomination-pools"
    bump: "major"
  - name: "pallet-society"
    bump: "major"
  - name: "frame-support"
    bump: "major"
  - name: "pallet-uniques"
    bump: "major"
  - name: "polkadot-runtime-parachains"
    bump: "major"
  - name: "polkadot-runtime-common"
    bump: "major"