Implements pallet versioning

frame/support/procedural/src/lib.rs

@@ -21,6 +21,7 @@
 
 mod storage;
 mod construct_runtime;
+mod pallet_version;
 mod transactional;
 
 use proc_macro::TokenStream;
@@ -325,3 +326,8 @@ pub fn construct_runtime(input: TokenStream) -> TokenStream {
 pub fn transactional(attr: TokenStream, input: TokenStream) -> TokenStream {
 	transactional::transactional(attr, input).unwrap_or_else(|e| e.to_compile_error().into())
 }
+
+#[proc_macro]
+pub fn crate_to_pallet_version(input: TokenStream) -> TokenStream {
+	pallet_version::crate_to_pallet_version(input).unwrap_or_else(|e| e.to_compile_error()).into()
+}

frame/support/procedural/src/pallet_version.rs

@@ -0,0 +1,64 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2020 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Implementation of macros related to pallet versioning.
+
+use proc_macro2::{TokenStream, Span};
+use syn::{Result, Error};
+use std::{env, str::FromStr};
+use frame_support_procedural_tools::generate_crate_access_2018;
+
+/// Get the version from the given version environment variable.
+///
+/// The version is parsed into the requested destination type.
+fn get_version<T: FromStr>(version_env: &str) -> std::result::Result<T, ()> {
+	let version = env::var(version_env)
+		.expect(&format!("`{}` is always set by cargo; qed", version_env));
+
+	T::from_str(&version).map_err(drop)
+}
+
+/// Create an error that will be shown by rustc at the call site of the macro.
+fn create_error(message: &str) -> Error {
+	Error::new(Span::call_site(), message)
+}
+
+/// Implementation of the `crate_to_pallet_version!` macro.
+pub fn crate_to_pallet_version(input: proc_macro::TokenStream) -> Result<TokenStream> {
+	if !input.is_empty() {
+		return Err(create_error("No arguments expected!"))
+	}
+
+	let major_version = get_version::<u16>("CARGO_PKG_VERSION_MAJOR")
+		.map_err(|_| create_error("Major version needs to fit into `u16`"))?;
+
+	let minor_version = get_version::<u8>("CARGO_PKG_VERSION_MINOR")
+		.map_err(|_| create_error("Minor version needs to fit into `u8`"))?;
+
+	let patch_version = get_version::<u8>("CARGO_PKG_VERSION_PATCH")
+		.map_err(|_| create_error("Patch version needs to fit into `u8`"))?;
+
+	let crate_ = generate_crate_access_2018()?;
+
+	Ok(quote::quote! {
+		#crate_::traits::PalletVersion {
+			major: #major_version,
+			minor: #minor_version,
+			patch: #patch_version,
+		}
+	})
+}

frame/support/src/dispatch.rs

@@ -29,7 +29,9 @@ pub use crate::weights::{
 	PaysFee, PostDispatchInfo, WithPostDispatchInfo,
 };
 pub use sp_runtime::{traits::Dispatchable, DispatchError};
-pub use crate::traits::{CallMetadata, GetCallMetadata, GetCallName, UnfilteredDispatchable};
+pub use crate::traits::{
+	CallMetadata, GetCallMetadata, GetCallName, UnfilteredDispatchable, GetPalletVersion,
+};
 
 /// The return typ of a `Dispatchable` in frame. When returned explicitly from
 /// a dispatchable function it allows overriding the default `PostDispatchInfo`
@@ -230,11 +232,11 @@ impl<T> Parameter for T where T: Codec + EncodeLike + Clone + Eq + fmt::Debug {}
 /// # #[macro_use]
 /// # extern crate frame_support;
 /// # use frame_support::dispatch;
-/// # use frame_system::{self as system, ensure_signed};
+/// # use frame_system::ensure_signed;
 /// # pub struct DefaultInstance;
-/// # pub trait Instance {}
+/// # pub trait Instance: 'static {}
 /// # impl Instance for DefaultInstance {}
-/// pub trait Trait<I: Instance=DefaultInstance>: system::Trait {}
+/// pub trait Trait<I: Instance=DefaultInstance>: frame_system::Trait {}
 ///
 /// decl_module! {
 /// 	pub struct Module<T: Trait<I>, I: Instance = DefaultInstance> for enum Call where origin: T::Origin {
@@ -1310,6 +1312,7 @@ macro_rules! decl_module {
 	};
 
 	(@impl_on_runtime_upgrade
+		{ $system:ident }
 		$module:ident<$trait_instance:ident: $trait_name:ident$(<I>, $instance:ident: $instantiable:path)?>;
 		{ $( $other_where_bounds:tt )* }
 		fn on_runtime_upgrade() -> $return:ty { $( $impl:tt )* }
@@ -1320,19 +1323,40 @@ macro_rules! decl_module {
 		{
 			fn on_runtime_upgrade() -> $return {
 				$crate::sp_tracing::enter_span!($crate::sp_tracing::trace_span!("on_runtime_upgrade"));
-				{ $( $impl )* }
+				let result = { $( $impl )* };
+
+				let key = $crate::traits::PalletVersion::storage_key::<
+						<$trait_instance as $system::Trait>::PalletInfo, Self
+					>().expect("Every active pallet has a name in the runtime; qed");
+				let version = $crate::crate_to_pallet_version!();
+				$crate::storage::unhashed::put(&key, &version);
+
+				result
 			}
 		}
 	};
 
 	(@impl_on_runtime_upgrade
+		{ $system:ident }
 		$module:ident<$trait_instance:ident: $trait_name:ident$(<I>, $instance:ident: $instantiable:path)?>;
 		{ $( $other_where_bounds:tt )* }
 	) => {
 		impl<$trait_instance: $trait_name$(<I>, $instance: $instantiable)?>
 			$crate::traits::OnRuntimeUpgrade
 			for $module<$trait_instance$(, $instance)?> where $( $other_where_bounds )*
-		{}
+		{
+			fn on_runtime_upgrade() -> $crate::dispatch::Weight {
+				$crate::sp_tracing::enter_span!($crate::sp_tracing::trace_span!("on_runtime_upgrade"));
+
+				let key = $crate::traits::PalletVersion::storage_key::<
+						<$trait_instance as $system::Trait>::PalletInfo, Self
+					>().expect("Every active pallet has a name in the runtime; qed");
+				let version = $crate::crate_to_pallet_version!();
+				$crate::storage::unhashed::put(&key, &version);
+
+				0
+			}
+		}
 	};
 
 	(@impl_integrity_test
@@ -1652,6 +1676,7 @@ macro_rules! decl_module {
 
 		$crate::decl_module! {
 			@impl_on_runtime_upgrade
+			{ $system }
 			$mod_type<$trait_instance: $trait_name $(<I>, $instance: $instantiable)?>;
 			{ $( $other_where_bounds )* }
 			$( $on_runtime_upgrade )*
@@ -1787,6 +1812,31 @@ macro_rules! decl_module {
 			}
 		}
 
+		// Bring `GetPalletVersion` into scope to make it easily usable.
+		pub use $crate::traits::GetPalletVersion as _;
+		// Implement `GetPalletVersion` for `Module`
+		impl<$trait_instance: $trait_name $(<I>, $instance: $instantiable)?> $crate::traits::GetPalletVersion
+			for $mod_type<$trait_instance $(, $instance)?> where $( $other_where_bounds )*
+		{
+			fn current_version() -> $crate::traits::PalletVersion {
+				$crate::crate_to_pallet_version!()
+			}
+
+			fn storage_version() -> $crate::traits::PalletVersion {
+				let key = $crate::traits::PalletVersion::storage_key::<
+						<$trait_instance as $system::Trait>::PalletInfo, Self
+					>().expect("Every active pallet has a name in the runtime; qed");
+
+				let value: Option<$crate::traits::PalletVersion> =
+					$crate::storage::unhashed::get(&key);
+
+				match value {
+					Some(version) => version,
+					None => $crate::crate_to_pallet_version!(),
+				}
+			}
+		}
+
 		// manual implementation of clone/eq/partialeq because using derive erroneously requires
 		// clone/eq/partialeq from T.
 		impl<$trait_instance: $trait_name $(<I>, $instance: $instantiable)?> $crate::dispatch::Clone
@@ -1802,6 +1852,7 @@ macro_rules! decl_module {
 				}
 			}
 		}
+
 		impl<$trait_instance: $trait_name $(<I>, $instance: $instantiable)?> $crate::dispatch::PartialEq
 			for $call_type<$trait_instance $(, $instance)?> where $( $other_where_bounds )*
 		{
@@ -1824,6 +1875,7 @@ macro_rules! decl_module {
 				}
 			}
 		}
+
 		impl<$trait_instance: $trait_name $(<I>, $instance: $instantiable)?> $crate::dispatch::Eq
 			for $call_type<$trait_instance $(, $instance)?> where $( $other_where_bounds )*
 		{}
@@ -2365,12 +2417,13 @@ mod tests {
 	pub mod system {
 		use codec::{Encode, Decode};
 
-		pub trait Trait {
+		pub trait Trait: 'static {
 			type AccountId;
 			type Call;
 			type BaseCallFilter;
 			type Origin: crate::traits::OriginTrait<Call = Self::Call>;
 			type BlockNumber: Into<u32>;
+			type PalletInfo: crate::traits::PalletInfo;
 		}
 
 		#[derive(Clone, PartialEq, Eq, Debug, Encode, Decode)]
@@ -2514,6 +2567,7 @@ mod tests {
 		type Call = OuterCall;
 		type BaseCallFilter = ();
 		type BlockNumber = u32;
+		type PalletInfo = ();
 	}
 
 	#[test]
@@ -2569,7 +2623,9 @@ mod tests {
 
 	#[test]
 	fn on_runtime_upgrade_should_work() {
-		assert_eq!(<Module<TraitImpl> as OnRuntimeUpgrade>::on_runtime_upgrade(), 10);
+		sp_io::TestExternalities::default().execute_with(||
+			assert_eq!(<Module<TraitImpl> as OnRuntimeUpgrade>::on_runtime_upgrade(), 10)
+		);
 	}
 
 	#[test]