pallet macro: always generate storage info on pallet struct (#9246)

* always implement storage info on Pallet

* fix UI test

* Fold span computation into trait and method computation

Co-authored-by: Keith Yeung <kungfukeith11@gmail.com>

substrate/frame/support/src/lib.rs

@@ -1430,6 +1430,8 @@ pub mod pallet_prelude {
 /// If the attribute set_storage_max_encoded_len is set then the macro call
 /// [`traits::StorageInfoTrait`] for each storage in the implementation of
 /// [`traits::StorageInfoTrait`] for the pallet.
+/// Otherwise it implements [`traits::StorageInfoTrait`] for the pallet using the
+/// [`traits::PartialStorageInfoTrait`] implementation of storages.
 ///
 /// # Hooks: `#[pallet::hooks]` optional
 ///

substrate/frame/support/src/storage/types/double_map.rs

@@ -499,6 +499,32 @@ where
 	}
 }
 
+/// It doesn't require to implement `MaxEncodedLen` and give no information for `max_size`.
+impl<Prefix, Hasher1, Hasher2, Key1, Key2, Value, QueryKind, OnEmpty, MaxValues>
+	crate::traits::PartialStorageInfoTrait for
+	StorageDoubleMap<Prefix, Hasher1, Key1, Hasher2, Key2, Value, QueryKind, OnEmpty, MaxValues>
+where
+	Prefix: StorageInstance,
+	Hasher1: crate::hash::StorageHasher,
+	Hasher2: crate::hash::StorageHasher,
+	Key1: FullCodec,
+	Key2: FullCodec,
+	Value: FullCodec,
+	QueryKind: QueryKindTrait<Value, OnEmpty>,
+	OnEmpty: Get<QueryKind::Query> + 'static,
+	MaxValues: Get<Option<u32>>,
+{
+	fn partial_storage_info() -> Vec<StorageInfo> {
+		vec![
+			StorageInfo {
+				prefix: Self::final_prefix(),
+				max_values: MaxValues::get(),
+				max_size: None
+			}
+		]
+	}
+}
+
 #[cfg(test)]
 mod test {
 	use super::*;

substrate/frame/support/src/storage/types/map.rs

@@ -375,6 +375,30 @@ where
 	}
 }
 
+/// It doesn't require to implement `MaxEncodedLen` and give no information for `max_size`.
+impl<Prefix, Hasher, Key, Value, QueryKind, OnEmpty, MaxValues>
+	crate::traits::PartialStorageInfoTrait for
+	StorageMap<Prefix, Hasher, Key, Value, QueryKind, OnEmpty, MaxValues>
+where
+	Prefix: StorageInstance,
+	Hasher: crate::hash::StorageHasher,
+	Key: FullCodec,
+	Value: FullCodec,
+	QueryKind: QueryKindTrait<Value, OnEmpty>,
+	OnEmpty: Get<QueryKind::Query> + 'static,
+	MaxValues: Get<Option<u32>>,
+{
+	fn partial_storage_info() -> Vec<StorageInfo> {
+		vec![
+			StorageInfo {
+				prefix: Self::final_prefix(),
+				max_values: MaxValues::get(),
+				max_size: None,
+			}
+		]
+	}
+}
+
 #[cfg(test)]
 mod test {
 	use super::*;

substrate/frame/support/src/storage/types/nmap.rs

@@ -430,6 +430,28 @@ where
 	}
 }
 
+/// It doesn't require to implement `MaxEncodedLen` and give no information for `max_size`.
+impl<Prefix, Key, Value, QueryKind, OnEmpty, MaxValues>
+	crate::traits::PartialStorageInfoTrait for
+	StorageNMap<Prefix, Key, Value, QueryKind, OnEmpty, MaxValues>
+where
+	Prefix: StorageInstance,
+	Key: super::key::KeyGenerator,
+	Value: FullCodec,
+	QueryKind: QueryKindTrait<Value, OnEmpty>,
+	OnEmpty: Get<QueryKind::Query> + 'static,
+	MaxValues: Get<Option<u32>>,
+{
+	fn partial_storage_info() -> Vec<StorageInfo> {
+		vec![
+			StorageInfo {
+				prefix: Self::final_prefix(),
+				max_values: MaxValues::get(),
+				max_size: None,
+			}
+		]
+	}
+}
 #[cfg(test)]
 mod test {
 	use super::*;

substrate/frame/support/src/storage/types/value.rs

@@ -228,6 +228,27 @@ where
 	}
 }
 
+/// It doesn't require to implement `MaxEncodedLen` and give no information for `max_size`.
+impl<Prefix, Value, QueryKind, OnEmpty>
+	crate::traits::PartialStorageInfoTrait for
+	StorageValue<Prefix, Value, QueryKind, OnEmpty>
+where
+	Prefix: StorageInstance,
+	Value: FullCodec,
+	QueryKind: QueryKindTrait<Value, OnEmpty>,
+	OnEmpty: crate::traits::Get<QueryKind::Query> + 'static
+{
+	fn partial_storage_info() -> Vec<StorageInfo> {
+		vec![
+			StorageInfo {
+				prefix: Self::hashed_key(),
+				max_values: Some(1),
+				max_size: None,
+			}
+		]
+	}
+}
+
 #[cfg(test)]
 mod test {
 	use super::*;

substrate/frame/support/src/traits.rs

@@ -74,7 +74,7 @@ pub use hooks::GenesisBuild;
 
 pub mod schedule;
 mod storage;
-pub use storage::{Instance, StorageInstance, StorageInfo, StorageInfoTrait};
+pub use storage::{Instance, PartialStorageInfoTrait, StorageInstance, StorageInfo, StorageInfoTrait};
 
 mod dispatch;
 pub use dispatch::{EnsureOrigin, OriginTrait, UnfilteredDispatchable};

substrate/frame/support/src/traits/storage.rs

@@ -74,3 +74,11 @@ impl StorageInfoTrait for Tuple {
 		res
 	}
 }
+
+/// Similar to [`StorageInfoTrait`], a trait to give partial information about storage.
+///
+/// This is useful when a type can give some partial information with its generic parameter doesn't
+/// implement some bounds.
+pub trait PartialStorageInfoTrait {
+	fn partial_storage_info() -> Vec<StorageInfo>;
+}