From 2cabedc223c615d39d10cb755ee934dc697e4bcb Mon Sep 17 00:00:00 2001
From: Steve Degosserie <723552+stiiifff@users.noreply.github.com>
Date: Mon, 31 Mar 2025 20:37:59 +0200
Subject: [PATCH] Fix FindAuthorAdapter (#19)

Current implementation was incorrect as `Babe::find_author` returns an
index, not the author's account.
Deferred the logic of looking up the author's account based on the index
to the `pallet_session::FindAccountFromAuthorIndex` function, and use
the existing conversion from `AccountId20` to `H160`.
---
 operator/runtime/src/configs/mod.rs | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/operator/runtime/src/configs/mod.rs b/operator/runtime/src/configs/mod.rs
index f61fe23f..c7a1b9b3 100644
--- a/operator/runtime/src/configs/mod.rs
+++ b/operator/runtime/src/configs/mod.rs
@@ -340,16 +340,18 @@ impl FeeCalculator for TransactionPaymentAsGasPrice {
     }
 }
 
-pub struct FindAuthorAdapter;
-impl FindAuthor<H160> for FindAuthorAdapter {
+pub struct FindAuthorAdapter<T>(core::marker::PhantomData<T>);
+impl<T> FindAuthor<H160> for FindAuthorAdapter<T>
+where
+    T: frame_system::Config + pallet_session::Config,
+    <T as pallet_session::Config>::ValidatorId: Into<H160>,
+{
     fn find_author<'a, I>(digests: I) -> Option<H160>
     where
         I: 'a + IntoIterator<Item = (sp_runtime::ConsensusEngineId, &'a [u8])>,
     {
-        if let Some(author) = Babe::find_author(digests) {
-            return Some(H160::from_slice(&author.encode()[0..20]));
-        }
-        None
+        pallet_session::FindAccountFromAuthorIndex::<T, Babe>::find_author(digests)
+            .map(|author| author.into())
     }
 }
 
@@ -383,7 +385,7 @@ impl pallet_evm::Config for Runtime {
     type Runner = pallet_evm::runner::stack::Runner<Self>;
     type OnChargeTransaction = OnChargeEVMTransaction<()>;
     type OnCreate = ();
-    type FindAuthor = FindAuthorAdapter;
+    type FindAuthor = FindAuthorAdapter<Self>;
     type GasLimitPovSizeRatio = GasLimitPovSizeRatio;
     type GasLimitStorageGrowthRatio = ();
     type Timestamp = Timestamp;