Allow renaming storage item prefixes (#9016)

* Implement parsing for #[pallet::storage_name] on storage items

* Rename storage prefix when a #[pallet::storage_name] is supplied

* Fix test_storage_info

* Rename storage_name to storage_prefix

* Check for duplicates when renaming storage prefixes

* Allow only string literals for storage_prefix renames

* Use proper spans for attribute errors

* Check for valid identifiers when parsing storage prefix renames

substrate/frame/support/test/tests/pallet.rs

@@ -198,6 +198,10 @@ pub mod pallet {
 	#[pallet::storage]
 	pub type Value<T> = StorageValue<Value = u32>;
 
+	#[pallet::storage]
+	#[pallet::storage_prefix = "Value2"]
+	pub type RenamedValue<T> = StorageValue<Value = u64>;
+
 	#[pallet::type_value]
 	pub fn MyDefault<T: Config>() -> u16
 	where T::AccountId: From<SomeType7> + From<SomeType1> + SomeAssociation1
@@ -577,6 +581,10 @@ fn storage_expand() {
 		let k = [twox_128(b"Example"), twox_128(b"Value")].concat();
 		assert_eq!(unhashed::get::<u32>(&k), Some(1u32));
 
+		pallet::RenamedValue::<Runtime>::put(2);
+		let k = [twox_128(b"Example"), twox_128(b"Value2")].concat();
+		assert_eq!(unhashed::get::<u64>(&k), Some(2));
+
 		pallet::Map::<Runtime>::insert(1, 2);
 		let mut k = [twox_128(b"Example"), twox_128(b"Map")].concat();
 		k.extend(1u8.using_encoded(blake2_128_concat));
@@ -697,6 +705,13 @@ fn metadata() {
 					default: DecodeDifferent::Decoded(vec![0]),
 					documentation: DecodeDifferent::Decoded(vec![]),
 				},
+				StorageEntryMetadata {
+					name: DecodeDifferent::Decoded("Value2".to_string()),
+					modifier: StorageEntryModifier::Optional,
+					ty: StorageEntryType::Plain(DecodeDifferent::Decoded("u64".to_string())),
+					default: DecodeDifferent::Decoded(vec![0]),
+					documentation: DecodeDifferent::Decoded(vec![]),
+				},
 				StorageEntryMetadata {
 					name: DecodeDifferent::Decoded("Map".to_string()),
 					modifier: StorageEntryModifier::Default,
@@ -993,6 +1008,11 @@ fn test_storage_info() {
 				max_values: Some(1),
 				max_size: Some(4),
 			},
+			StorageInfo {
+				prefix: prefix(b"Example", b"Value2"),
+				max_values: Some(1),
+				max_size: Some(8),
+			},
 			StorageInfo {
 				prefix: prefix(b"Example", b"Map"),
 				max_values: None,

substrate/frame/support/test/tests/pallet_ui/duplicate_storage_prefix.rs

@@ -0,0 +1,21 @@
+#[frame_support::pallet]
+mod pallet {
+	use frame_support::pallet_prelude::StorageValue;
+
+	#[pallet::config]
+	pub trait Config: frame_system::Config {}
+
+	#[pallet::pallet]
+	#[pallet::generate_store(trait Store)]
+	pub struct Pallet<T>(core::marker::PhantomData<T>);
+
+	#[pallet::storage]
+	type Foo<T> = StorageValue<_, u8>;
+
+    #[pallet::storage]
+    #[pallet::storage_prefix = "Foo"]
+    type NotFoo<T> = StorageValue<_, u16>;
+}
+
+fn main() {
+}

substrate/frame/support/test/tests/pallet_ui/duplicate_storage_prefix.stderr

@@ -0,0 +1,17 @@
+error: Duplicate storage prefixes found for `Foo`
+  --> $DIR/duplicate_storage_prefix.rs:16:32
+   |
+16 |     #[pallet::storage_prefix = "Foo"]
+   |                                ^^^^^
+
+error[E0412]: cannot find type `_GeneratedPrefixForStorageFoo` in this scope
+  --> $DIR/duplicate_storage_prefix.rs:13:7
+   |
+13 |     type Foo<T> = StorageValue<_, u8>;
+   |          ^^^ not found in this scope
+
+error[E0121]: the type placeholder `_` is not allowed within types on item signatures
+  --> $DIR/duplicate_storage_prefix.rs:17:35
+   |
+17 |     type NotFoo<T> = StorageValue<_, u16>;
+   |                                   ^ not allowed in type signatures

substrate/frame/support/test/tests/pallet_ui/storage_invalid_attribute.rs

@@ -0,0 +1,21 @@
+#[frame_support::pallet]
+mod pallet {
+	use frame_support::pallet_prelude::Hooks;
+	use frame_system::pallet_prelude::BlockNumberFor;
+
+	#[pallet::config]
+	pub trait Config: frame_system::Config {}
+
+	#[pallet::pallet]
+	pub struct Pallet<T>(_);
+
+	#[pallet::call]
+	impl<T: Config> Pallet<T> {}
+
+	#[pallet::storage]
+	#[pallet::generate_store(pub trait Store)]
+	type Foo<T> = StorageValue<u8, u8>;
+}
+
+fn main() {
+}

substrate/frame/support/test/tests/pallet_ui/storage_invalid_attribute.stderr

@@ -0,0 +1,5 @@
+error: expected `getter` or `storage_prefix`
+  --> $DIR/storage_invalid_attribute.rs:16:12
+   |
+16 |     #[pallet::generate_store(pub trait Store)]
+   |               ^^^^^^^^^^^^^^

substrate/frame/support/test/tests/pallet_ui/storage_invalid_rename_value.rs

@@ -0,0 +1,18 @@
+#[frame_support::pallet]
+mod pallet {
+	use frame_support::pallet_prelude::Hooks;
+	use frame_system::pallet_prelude::BlockNumberFor;
+
+	#[pallet::config]
+	pub trait Config: frame_system::Config {}
+
+	#[pallet::pallet]
+	pub struct Pallet<T>(core::marker::PhantomData<T>);
+
+	#[pallet::storage]
+	#[pallet::storage_prefix = "pub"]
+	type Foo<T> = StorageValue<_, u8>;
+}
+
+fn main() {
+}

substrate/frame/support/test/tests/pallet_ui/storage_invalid_rename_value.stderr

@@ -0,0 +1,5 @@
+error: `pub` is not a valid identifier
+  --> $DIR/storage_invalid_rename_value.rs:13:29
+   |
+13 |     #[pallet::storage_prefix = "pub"]
+   |                                ^^^^^

substrate/frame/support/test/tests/pallet_ui/storage_multiple_getters.rs

@@ -0,0 +1,25 @@
+#[frame_support::pallet]
+mod pallet {
+	use frame_support::pallet_prelude::Hooks;
+	use frame_system::pallet_prelude::BlockNumberFor;
+
+	#[pallet::config]
+	pub trait Config: frame_system::Config {}
+
+	#[pallet::pallet]
+	pub struct Pallet<T>(core::marker::PhantomData<T>);
+
+	#[pallet::hooks]
+	impl<T: Config> Hooks<BlockNumberFor<T>> for Pallet<T> {}
+
+	#[pallet::call]
+	impl<T: Config> Pallet<T> {}
+
+	#[pallet::storage]
+	#[pallet::getter(fn get_foo)]
+	#[pallet::getter(fn foo_error)]
+	type Foo<T> = StorageValue<_, u8>;
+}
+
+fn main() {
+}

substrate/frame/support/test/tests/pallet_ui/storage_multiple_getters.stderr

@@ -0,0 +1,5 @@
+error: Invalid pallet::storage, multiple argument pallet::getter found
+  --> $DIR/storage_multiple_getters.rs:20:3
+   |
+20 |     #[pallet::getter(fn foo_error)]
+   |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

substrate/frame/support/test/tests/pallet_ui/storage_multiple_renames.rs

@@ -0,0 +1,25 @@
+#[frame_support::pallet]
+mod pallet {
+	use frame_support::pallet_prelude::Hooks;
+	use frame_system::pallet_prelude::BlockNumberFor;
+
+	#[pallet::config]
+	pub trait Config: frame_system::Config {}
+
+	#[pallet::pallet]
+	pub struct Pallet<T>(core::marker::PhantomData<T>);
+
+	#[pallet::hooks]
+	impl<T: Config> Hooks<BlockNumberFor<T>> for Pallet<T> {}
+
+	#[pallet::call]
+	impl<T: Config> Pallet<T> {}
+
+	#[pallet::storage]
+	#[pallet::storage_prefix = "Bar"]
+	#[pallet::storage_prefix = "Baz"]
+	type Foo<T> = StorageValue<_, u8>;
+}
+
+fn main() {
+}

substrate/frame/support/test/tests/pallet_ui/storage_multiple_renames.stderr

@@ -0,0 +1,5 @@
+error: Invalid pallet::storage, multiple argument pallet::storage_prefix found
+  --> $DIR/storage_multiple_renames.rs:20:3
+   |
+20 |     #[pallet::storage_prefix = "Baz"]
+   |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^