Companion PR for substrate PR 8072 - Add a config field to babe epochs (#2467)

* Add a config field to babe epochs

* Fix test

* Add BABE_GENESIS_EPOCH_CONFIG consts

* Use PrimaryAndSecondaryVRFSlots and remove newlines

* Make epoch_configs Some

* Fix tests

* Fix test service tests

* Add a BabeEpochConfigMigrations OnRuntimeUpgrade

* Apply suggestions

* Use PrimaryAndSecondaryPlainSlots in kusama

* Remove migration from test runtime and rococo

* Add HasPalletPrefix

* Rename to BabePalletPrefix and change BabeApi -> Babe

* "Update Substrate"

* Update substrate

* Resolve parantheses errors

Co-authored-by: parity-processbot <>

polkadot/runtime/westend/src/lib.rs

@@ -96,6 +96,13 @@ pub const VERSION: RuntimeVersion = RuntimeVersion {
 	transaction_version: 4,
 };
 
+/// The BABE epoch configuration at genesis.
+pub const BABE_GENESIS_EPOCH_CONFIG: babe_primitives::BabeEpochConfiguration =
+	babe_primitives::BabeEpochConfiguration {
+		c: PRIMARY_PROBABILITY,
+		allowed_slots: babe_primitives::AllowedSlots::PrimaryAndSecondaryVRFSlots
+	};
+
 /// Native version.
 #[cfg(any(feature = "std", test))]
 pub fn native_version() -> NativeVersion {
@@ -743,6 +750,21 @@ construct_runtime! {
 	}
 }
 
+impl pallet_babe::migrations::BabePalletPrefix for Runtime {
+	fn pallet_prefix() -> &'static str {
+		"Babe"
+	}
+}
+
+pub struct BabeEpochConfigMigrations;
+impl frame_support::traits::OnRuntimeUpgrade for BabeEpochConfigMigrations {
+	fn on_runtime_upgrade() -> frame_support::weights::Weight {
+		pallet_babe::migrations::add_epoch_configuration::<Runtime>(
+			BABE_GENESIS_EPOCH_CONFIG,
+		)
+	}
+}
+
 /// The address format for describing accounts.
 pub type Address = sp_runtime::MultiAddress<AccountId, ()>;
 /// Block header type as expected by this runtime.
@@ -774,6 +796,7 @@ pub type Executive = frame_executive::Executive<
 	frame_system::ChainContext<Runtime>,
 	Runtime,
 	AllModules,
+	BabeEpochConfigMigrations,
 >;
 /// The payload being signed in transactions.
 pub type SignedPayload = generic::SignedPayload<Call, SignedExtra>;
@@ -951,10 +974,10 @@ sp_api::impl_runtime_apis! {
 			babe_primitives::BabeGenesisConfiguration {
 				slot_duration: Babe::slot_duration(),
 				epoch_length: EpochDuration::get(),
-				c: PRIMARY_PROBABILITY,
+				c: BABE_GENESIS_EPOCH_CONFIG.c,
 				genesis_authorities: Babe::authorities(),
 				randomness: Babe::randomness(),
-				allowed_slots: babe_primitives::AllowedSlots::PrimaryAndSecondaryVRFSlots,
+				allowed_slots: BABE_GENESIS_EPOCH_CONFIG.allowed_slots,
 			}
 		}