Emit ContractCodeUpdated when setting new code_hash

frame/contracts/src/exec.rs

@@ -1026,6 +1026,10 @@ where
 		top_frame.contract_info().code_hash = hash;
 		increment_refcount::<Self::T>(hash)?;
 		decrement_refcount::<Self::T>(prev_hash)?;
+		Contracts::<Self::T>::deposit_event(Event::ContractCodeUpdated {
+			contract: top_frame.account_id.clone(),
+			code_hash: hash,
+		});
 		Ok(())
 	}
 

frame/contracts/src/lib.rs

@@ -559,6 +559,14 @@ pub mod pallet {
 
 		/// A code with the specified hash was removed.
 		CodeRemoved { code_hash: T::Hash },
+
+		/// Contract code has been updated to one specified with code_hash
+		ContractCodeUpdated {
+			/// The contract that has been updated.
+			contract: T::AccountId,
+			/// New code hash that was set for the contract
+			code_hash: T::Hash,
+		},
 	}
 
 	#[pallet::error]

frame/contracts/src/tests.rs

@@ -735,6 +735,19 @@ fn set_code_hash() {
 				.result
 				.unwrap();
 		assert_return_code!(result, 2);
+
+		// Checking for the last event only
+		assert_eq!(
+			System::events()[13],
+			EventRecord {
+				phase: Phase::Initialization,
+				event: Event::Contracts(crate::Event::ContractCodeUpdated {
+					contract: contract_addr.clone(),
+					code_hash: new_code_hash.clone(),
+				}),
+				topics: vec![],
+			},
+		);
 	});
 }