TryDecodeEntireState check for storage types and pallets (#1805)

### This PR is a port of this [PR for
substrate](https://github.com/paritytech/substrate/pull/13013) by
@kianenigma

Add infrastructure needed to have a Pallet::decode_entire_state(), which
makes sure all "typed" storage items defined in the pallet are
decode-able.

This is not enforced in any way at the moment. Teams who wish to
integrate/use this in the try-runtime feature flag should add
frame_support::storage::migration::EnsureStateDecodes as the LAST ITEM
of the runtime's custom migrations, and pass it to frame-executive. This
will make it usable in try-runtime on-runtime-upgrade.

This now catches cases like
https://github.com/paritytech/polkadot-sdk/pull/1969:
```pre
ERROR runtime::executive] failed to decode the value at key: Failed to decode value at key: 0x94eadf0156a8ad5156507773d0471e4ab8ebad86f546c7e0b135a4212aace339. Storage info StorageInfo { pallet_name: Ok("ParaScheduler"), storage_name: Ok("AvailabilityCores"), prefix: Err(Utf8Error { valid_up_to: 0, error_len: Some(1) }), max_values: Some(1), max_size: None }. Raw value: Some("0x0c010101010101")
```

... or:

![image](https://github.com/paritytech/polkadot-sdk/assets/10380170/73052d4f-4da5-4b21-a8dd-b17004e5965e)

Closes #241

---------

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>
Co-authored-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>
Co-authored-by: Liam Aharon <liam.aharon@hotmail.com>

substrate/frame/support/src/storage/generator/mod.rs

@@ -24,10 +24,10 @@
 //!
 //! This is internal api and is subject to change.
 
-mod double_map;
+pub(crate) mod double_map;
 pub(crate) mod map;
-mod nmap;
-mod value;
+pub(crate) mod nmap;
+pub(crate) mod value;
 
 pub use double_map::StorageDoubleMap;
 pub use map::StorageMap;

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

@@ -119,7 +119,11 @@ impl<P: CountedStorageMapInstance, H, K, V, Q, O, M> MapWrapper
 	type Map = StorageMap<P, H, K, V, Q, O, M>;
 }
 
-type CounterFor<P> = StorageValue<<P as CountedStorageMapInstance>::CounterPrefix, u32, ValueQuery>;
+/// The numeric counter type.
+pub type Counter = u32;
+
+type CounterFor<P> =
+	StorageValue<<P as CountedStorageMapInstance>::CounterPrefix, Counter, ValueQuery>;
 
 /// On removal logic for updating counter while draining upon some prefix with
 /// [`crate::storage::PrefixIterator`].
@@ -423,14 +427,14 @@ where
 	/// can be very heavy, so use with caution.
 	///
 	/// Returns the number of items in the map which is used to set the counter.
-	pub fn initialize_counter() -> u32 {
-		let count = Self::iter_values().count() as u32;
+	pub fn initialize_counter() -> Counter {
+		let count = Self::iter_values().count() as Counter;
 		CounterFor::<Prefix>::set(count);
 		count
 	}
 
 	/// Return the count.
-	pub fn count() -> u32 {
+	pub fn count() -> Counter {
 		CounterFor::<Prefix>::get()
 	}
 }
@@ -1207,7 +1211,7 @@ mod test {
 				StorageEntryMetadataIR {
 					name: "counter_for_foo",
 					modifier: StorageEntryModifierIR::Default,
-					ty: StorageEntryTypeIR::Plain(scale_info::meta_type::<u32>()),
+					ty: StorageEntryTypeIR::Plain(scale_info::meta_type::<Counter>()),
 					default: vec![0, 0, 0, 0],
 					docs: if cfg!(feature = "no-metadata-docs") {
 						vec![]

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

@@ -114,8 +114,10 @@ impl<P: CountedStorageNMapInstance, K, V, Q, O, M> MapWrapper
 	type Map = StorageNMap<P, K, V, Q, O, M>;
 }
 
+type Counter = super::counted_map::Counter;
+
 type CounterFor<P> =
-	StorageValue<<P as CountedStorageNMapInstance>::CounterPrefix, u32, ValueQuery>;
+	StorageValue<<P as CountedStorageNMapInstance>::CounterPrefix, Counter, ValueQuery>;
 
 /// On removal logic for updating counter while draining upon some prefix with
 /// [`crate::storage::PrefixIterator`].
@@ -472,7 +474,7 @@ where
 	}
 
 	/// Return the count.
-	pub fn count() -> u32 {
+	pub fn count() -> Counter {
 		CounterFor::<Prefix>::get()
 	}
 }

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

@@ -30,7 +30,7 @@ mod map;
 mod nmap;
 mod value;
 
-pub use counted_map::{CountedStorageMap, CountedStorageMapInstance};
+pub use counted_map::{CountedStorageMap, CountedStorageMapInstance, Counter};
 pub use counted_nmap::{CountedStorageNMap, CountedStorageNMapInstance};
 pub use double_map::StorageDoubleMap;
 pub use key::{

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

@@ -23,7 +23,7 @@ use crate::{
 		types::{OptionQuery, QueryKindTrait, StorageEntryMetadataBuilder},
 		StorageAppend, StorageDecodeLength, StorageTryAppend,
 	},
-	traits::{GetDefault, StorageInfo, StorageInstance},
+	traits::{Get, GetDefault, StorageInfo, StorageInstance},
 };
 use codec::{Decode, Encode, EncodeLike, FullCodec, MaxEncodedLen};
 use frame_support::storage::StorageDecodeNonDedupLength;
@@ -72,7 +72,7 @@ where
 	Prefix: StorageInstance,
 	Value: FullCodec,
 	QueryKind: QueryKindTrait<Value, OnEmpty>,
-	OnEmpty: crate::traits::Get<QueryKind::Query> + 'static,
+	OnEmpty: Get<QueryKind::Query> + 'static,
 {
 	type Query = QueryKind::Query;
 	fn pallet_prefix() -> &'static [u8] {