From 83e8fe42215e9812672d2cc9647e8d3d3df47a00 Mon Sep 17 00:00:00 2001
From: Dmitry Sinyavin <dmitry.sinyavin@parity.io>
Date: Mon, 13 Feb 2023 21:07:28 +0100
Subject: [PATCH] Remove migration (again!)

---
 .../parachains/src/session_info/migration.rs  | 68 +------------------
 runtime/rococo/src/lib.rs                     |  1 -
 runtime/westend/src/lib.rs                    |  1 -
 3 files changed, 1 insertion(+), 69 deletions(-)

diff --git a/runtime/parachains/src/session_info/migration.rs b/runtime/parachains/src/session_info/migration.rs
index 00212e409034..c0ec1e5915bd 100644
--- a/runtime/parachains/src/session_info/migration.rs
+++ b/runtime/parachains/src/session_info/migration.rs
@@ -19,70 +19,4 @@
 use frame_support::traits::StorageVersion;
 
 /// The current storage version.
-pub const STORAGE_VERSION: StorageVersion = StorageVersion::new(2);
-
-pub mod v2 {
-	use super::STORAGE_VERSION;
-	#[cfg(feature = "try-runtime")]
-	use crate::session_info::Vec;
-	use crate::{session_info, session_info::Pallet, shared};
-	use frame_support::{
-		pallet_prelude::Weight,
-		traits::{OnRuntimeUpgrade, StorageVersion},
-	};
-	use frame_system::Config;
-	use primitives::vstaging::ExecutorParams;
-	use sp_core::Get;
-
-	const LOG_TARGET: &'static str = "runtime::session_info::migration::v2";
-
-	pub struct MigrateToV2<T>(sp_std::marker::PhantomData<T>);
-	impl<T: Config + session_info::pallet::Config> OnRuntimeUpgrade for MigrateToV2<T> {
-		fn on_runtime_upgrade() -> Weight {
-			// Bootstrap session executor params with the default ones if no parameters for the
-			// current session are in storage. `ExecutorParams::default()` is supposed to generate
-			// EXACTLY the same set of parameters the previous implementation used in a hard-coded
-			// form. This supposed to only run once, when upgrading from pre-parametrized executor
-			// code.
-			let db_weight = T::DbWeight::get();
-			let mut weight = db_weight.reads(1);
-			if StorageVersion::get::<Pallet<T>>() == 1 {
-				log::info!(target: LOG_TARGET, "Upgrading storage v1 -> v2");
-				let first_session = <session_info::Pallet<T>>::earliest_stored_session();
-				let current_session = <shared::Pallet<T>>::session_index();
-
-				for session_index in first_session..=current_session {
-					session_info::pallet::SessionExecutorParams::<T>::insert(
-						&session_index,
-						ExecutorParams::default(),
-					);
-				}
-
-				STORAGE_VERSION.put::<Pallet<T>>();
-				weight += db_weight.reads_writes(2, (current_session - first_session + 2) as u64);
-			} else {
-				log::warn!(target: LOG_TARGET, "Can only upgrade from version 1");
-			}
-			weight
-		}
-
-		#[cfg(feature = "try-runtime")]
-		fn pre_upgrade() -> Result<Vec<u8>, &'static str> {
-			log::info!(target: LOG_TARGET, "Performing pre-upgrade checks");
-			assert_eq!(StorageVersion::get::<Pallet<T>>(), 1);
-			let session_index = <shared::Pallet<T>>::session_index();
-			assert!(Pallet::<T>::session_executor_params(session_index).is_none());
-			Ok(Default::default())
-		}
-
-		#[cfg(feature = "try-runtime")]
-		fn post_upgrade(_: Vec<u8>) -> Result<(), &'static str> {
-			log::info!(target: LOG_TARGET, "Performing post-upgrade checks");
-			assert_eq!(StorageVersion::get::<Pallet<T>>(), 2);
-			let session_index = <shared::Pallet<T>>::session_index();
-			let executor_params = Pallet::<T>::session_executor_params(session_index);
-			assert_eq!(executor_params, Some(ExecutorParams::default()));
-			Ok(())
-		}
-	}
-}
+pub const STORAGE_VERSION: StorageVersion = StorageVersion::new(1);
diff --git a/runtime/rococo/src/lib.rs b/runtime/rococo/src/lib.rs
index 4c9d231a1b1a..cc268df94efd 100644
--- a/runtime/rococo/src/lib.rs
+++ b/runtime/rococo/src/lib.rs
@@ -1491,7 +1491,6 @@ pub type Migrations = (
 	// "Use 2D weights in XCM v3" <https://github.com/paritytech/polkadot/pull/6134>
 	pallet_xcm::migration::v1::MigrateToV1<Runtime>,
 	parachains_ump::migration::v1::MigrateToV1<Runtime>,
-	parachains_session_info::migration::v2::MigrateToV2<Runtime>,
 	// Remove stale entries in the set id -> session index storage map (after
 	// this release they will be properly pruned after the bonding duration has
 	// elapsed)
diff --git a/runtime/westend/src/lib.rs b/runtime/westend/src/lib.rs
index 6ef3e6ba834a..80f79898ae00 100644
--- a/runtime/westend/src/lib.rs
+++ b/runtime/westend/src/lib.rs
@@ -1247,7 +1247,6 @@ pub type Migrations = (
 	// "Use 2D weights in XCM v3" <https://github.com/paritytech/polkadot/pull/6134>
 	pallet_xcm::migration::v1::MigrateToV1<Runtime>,
 	parachains_ump::migration::v1::MigrateToV1<Runtime>,
-	parachains_session_info::migration::v2::MigrateToV2<Runtime>,
 	// Remove stale entries in the set id -> session index storage map (after
 	// this release they will be properly pruned after the bonding duration has
 	// elapsed)