petscheit/justification_problem

Justification validation:

There are inconsistencies between Polkadot & Kusama relaychains and the testnets (Rococo & Westend). We realized a couple of days ago that the verifications broke at some point for Rococo. Essentially it boils down to the signature checks returning false. A quick guide to reproduce:

Steps to Reproduce:

• run yarn to install TS dependencies.
• in getJustification.ts, select chain to receive justification from by setting the provider
• run ts-node getJustification.ts and copy encoded justifcation into main.rs (without leading 0x)
• run cargo run and copy target_hash from the console output
• use https://polkadot.js.org/apps/#/explorer to lookup currentSetID (chain_state -> grandpad -> currentSetID) and add target_hash as blockhash
• set returned ID as authorities_set_id in main.rs
• rerun cargo run

The following approach used to work with Rococo, but a couple of days ago, we realized this is not the case anymore. We thought updating to the newest finality_grandpa and sp_finality_grandpa versions will fix the issue, but it is persisting. Is this currently expected and the justification validation has changed? Or will this work again on Rococo in the future.