Ensure we don't set a storage version when the pallet is missing the …

…attribute

frame/support/procedural/src/pallet/expand/hooks.rs

@@ -109,7 +109,26 @@ pub fn expand_hooks(def: &mut Def) -> proc_macro2::TokenStream {
 			}
 		}
 	} else {
-		quote::quote! {}
+		quote::quote! {
+			let on_chain_version = <Self as #frame_support::traits::GetStorageVersion>::on_chain_storage_version();
+
+			if on_chain_version != #frame_support::traits::StorageVersion::new(0) {
+				let pallet_name = <
+					<T as #frame_system::Config>::PalletInfo
+					as
+					#frame_support::traits::PalletInfo
+				>::name::<Self>().unwrap_or("<unknown pallet name>");
+
+				#frame_support::log::error!(
+					target: #frame_support::LOG_TARGET,
+					"{pallet_name}: On chain storage version {on_chain_version:?} is set to non zero,\
+					 while the pallet is missing the `#[pallet::storage_version(VERSION)]` attribute.",
+				);
+
+				return Err("On chain storage version set, while pallet doesn't \
+							has the `#[pallet::storage_version(VERSION)]` attribute.");
+			}
+		}
 	};
 
 	quote::quote_spanned!(span =>

frame/support/test/tests/pallet.rs

@@ -40,7 +40,7 @@ use sp_runtime::{DispatchError, ModuleError};
 
 parameter_types! {
 	/// Used to control if the storage version should be updated.
-	static UpdateStorageVersion: bool = false;
+	storage UpdateStorageVersion: bool = false;
 }
 
 /// Latest stable metadata version used for testing.
@@ -2057,7 +2057,7 @@ fn test_storage_alias() {
 
 #[cfg(feature = "try-runtime")]
 #[test]
-fn post_runtime_upgrade_detects_missing_storage_version_change() {
+fn post_runtime_upgrade_detects_storage_version_issues() {
 	use frame_support::traits::UpgradeCheckSelect;
 
 	struct CustomUpgrade;
@@ -2070,6 +2070,16 @@ fn post_runtime_upgrade_detects_missing_storage_version_change() {
 		}
 	}
 
+	struct CustomUpgradePallet4;
+
+	impl OnRuntimeUpgrade for CustomUpgradePallet4 {
+		fn on_runtime_upgrade() -> Weight {
+			StorageVersion::new(100).put::<Example4>();
+
+			Default::default()
+		}
+	}
+
 	type Executive = frame_executive::Executive<
 		Runtime,
 		Block,
@@ -2087,6 +2097,15 @@ fn post_runtime_upgrade_detects_missing_storage_version_change() {
 		CustomUpgrade,
 	>;
 
+	type ExecutiveWithUpgradePallet4 = frame_executive::Executive<
+		Runtime,
+		Block,
+		frame_system::ChainContext<Runtime>,
+		Runtime,
+		AllPalletsWithSystem,
+		CustomUpgradePallet4,
+	>;
+
 	TestExternalities::default().execute_with(|| {
 		// Call `on_genesis` to put the storage version of `Example` into the storage.
 		Example::on_genesis();
@@ -2100,9 +2119,8 @@ fn post_runtime_upgrade_detects_missing_storage_version_change() {
 		// Call `on_genesis` to put the storage version of `Example` into the storage.
 		Example::on_genesis();
 		// We set the new storage version in the pallet and that should be detected.
-		UpdateStorageVersion::set(true);
+		UpdateStorageVersion::set(&true);
 		Executive::try_runtime_upgrade(UpgradeCheckSelect::PreAndPost).unwrap();
-		UpdateStorageVersion::set(false);
 	});
 
 	TestExternalities::default().execute_with(|| {
@@ -2111,6 +2129,19 @@ fn post_runtime_upgrade_detects_missing_storage_version_change() {
 		// We set the new storage version in the custom upgrade and that should be detected.
 		ExecutiveWithUpgrade::try_runtime_upgrade(UpgradeCheckSelect::PreAndPost).unwrap();
 	});
+
+	TestExternalities::default().execute_with(|| {
+		// Call `on_genesis` to put the storage version of `Example` into the storage.
+		Example::on_genesis();
+		// We need to set the correct storage version for `Example2`
+		UpdateStorageVersion::set(&true);
+
+		// `CustomUpgradePallet4` will set a storage version for `Example4` while this doesn't has
+		// any storage version "enabled".
+		assert!(ExecutiveWithUpgradePallet4::try_runtime_upgrade(UpgradeCheckSelect::PreAndPost)
+			.unwrap_err()
+			.contains("On chain storage version set, while pallet doesn't"));
+	});
 }
 
 #[test]