WIP

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

frame/support/src/traits.rs

@@ -74,7 +74,7 @@ pub use randomness::Randomness;
 
 mod metadata;
 pub use metadata::{
-	GetStorageVersions, CallMetadata, CrateVersion, GetCallMetadata, GetCallName, GetStorageVersion, PalletInfo,
+	GetStorageVersions, CallMetadata, CrateVersion, GetCallMetadata, GetCallName, GetStorageVersion, PalletInfo, CheckAllVersions,
 	PalletInfoAccess, PalletInfoData, PalletsInfoAccess, StorageVersion,
 	STORAGE_VERSION_STORAGE_KEY_POSTFIX,
 };

frame/support/src/traits/metadata.rs

@@ -212,6 +212,12 @@ impl StorageVersion {
 	}
 }
 
+impl core::fmt::Display for StorageVersion {
+	fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+		write!(f, "{}", self.0)
+	}
+}
+
 impl PartialEq<u16> for StorageVersion {
 	fn eq(&self, other: &u16) -> bool {
 		self.0 == *other
@@ -276,6 +282,70 @@ impl GetStorageVersions for Tuple {
 	}
 }
 
+use sp_weights::Weight;
+use crate::traits::OnRuntimeUpgrade;
+
+/// Put this as last into your Migrations with `AllPalletsWithSystem` as `T`.
+pub struct CheckAllVersions<T>(sp_std::marker::PhantomData<T>);
+impl<T: PalletsInfoAccess + GetStorageVersions> OnRuntimeUpgrade for CheckAllVersions<T> {
+	#[cfg(feature = "try-runtime")]
+	fn on_runtime_upgrade() -> Weight {
+		Weight::zero() // Check done by post_upgrade.
+	}
+
+	#[cfg(not(feature = "try-runtime"))]
+	fn on_runtime_upgrade() -> Weight {
+		if let Err(err) = Self::check() {
+			// Just log it. If you see this in production, then it is too late anyway.
+			log::error!(
+				target: "CheckPalletVersions",
+				"{:?}",
+				err
+			);
+			// TODO weight
+		};
+		Weight::zero()
+	}
+
+	#[cfg(feature = "try-runtime")]
+	fn post_upgrade(_: Vec<u8>) -> Result<(), &'static str> {
+		Self::check()
+	}
+}
+
+impl<T: PalletsInfoAccess + GetStorageVersions> CheckAllVersions<T> {
+	fn check() -> Result<(), &'static str> {
+		let pallets = <T as PalletsInfoAccess>::infos();
+		let onchain = <T as GetStorageVersions>::on_chain_storage_versions();
+		let storage = <T as GetStorageVersions>::current_storage_versions();
+		let versions = onchain.iter().zip(storage.iter());
+
+		let mut failed = false;
+		for (pallet, (onchain, storage)) in pallets.iter().zip(versions) {
+			if onchain != storage {
+				log::error!(
+					target: "CheckPalletVersions",
+					"Chain and code version mismatch for pallet {}: {} != {}",
+					pallet.name,
+					onchain,
+					storage,
+				);
+				failed = true;
+			}
+		}
+		if failed {
+			Err("One or more pallets have incorrect versions, see log.\n\
+			This is really bad and means that there are unusable pallets on the chain.")
+		} else {
+			log::info!(
+				target: "CheckPalletVersions",
+				"All pallets have the correct chain version."
+			);
+			Ok(())
+		}
+	}
+}
+
 #[cfg(test)]
 mod tests {
 	use super::*;