Found some areas for improvement while working on
https://github.com/polkadot-fellows/runtimes/pull/122.
## Improvements
- If multiple keys in a storage item (e.g. a map) are undecodable,
return all the undecodable keys rather than only the first one found
- Include the key of the undecodable storage in the INFO log
- Write output as hex string where appropriate
- Write INFO log on successful decoding
### 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:
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>
Liam Aharon