emit ConversionFailed instead of swallowing silently

Author: mrq1911

pallets/referrals/src/lib.rs

@@ -298,6 +298,11 @@ pub mod pallet {
 			from: AssetAmount<T::AssetId>,
 			to: AssetAmount<T::AssetId>,
 		},
+		/// A pending asset could not be converted; skipped, not blocking.
+		ConversionFailed {
+			asset_id: T::AssetId,
+			reason: DispatchError,
+		},
 		/// Rewards claimed.
 		Claimed {
 			who: T::AccountId,
@@ -484,12 +489,17 @@ pub mod pallet {
 				let asset_balance = T::Currency::balance(asset_id.clone(), &Self::pot_account_id());
 				// Best-effort, like `on_idle`: skip an un-convertible slice rather than revert the
 				// whole claim. Funds stay in the pot and re-queue on the next fee.
-				let _ = T::Convert::convert(
+				if let Err(reason) = T::Convert::convert(
 					Self::pot_account_id(),
 					asset_id.clone(),
 					T::RewardAsset::get(),
 					asset_balance,
-				);
+				) {
+					Self::deposit_event(Event::ConversionFailed {
+						asset_id: asset_id.clone(),
+						reason,
+					});
+				}
 				PendingConversions::<T>::remove(asset_id);
 			}
 			let referrer_shares = ReferrerShares::<T>::take(&who);
@@ -616,12 +626,17 @@ pub mod pallet {
 			for asset_id in PendingConversions::<T>::iter_keys().take(max_converts as usize) {
 				let asset_balance = T::Currency::balance(asset_id.clone(), &Self::pot_account_id());
 				// remove the asset_id from PendingConversions even when the conversion fails
-				let _ = T::Convert::convert(
+				if let Err(reason) = T::Convert::convert(
 					Self::pot_account_id(),
 					asset_id.clone(),
 					T::RewardAsset::get(),
 					asset_balance,
-				);
+				) {
+					Self::deposit_event(Event::ConversionFailed {
+						asset_id: asset_id.clone(),
+						reason,
+					});
+				}
 				PendingConversions::<T>::remove(asset_id);
 				actual_converts += 1;
 			}

pallets/referrals/src/tests/claim.rs

@@ -100,6 +100,11 @@ fn claim_rewards_should_succeed_when_pending_asset_balance_is_below_min_trading_
 			assert_eq!(Tokens::free_balance(HDX, &BOB), 5_000_000_000_000);
 			// The dust entry is dropped rather than left to block future claims.
 			assert_eq!(PendingConversions::<Test>::count(), 0);
+			// The skipped conversion is surfaced as an event, not silently swallowed.
+			assert!(System::events().iter().any(|r| matches!(
+				&r.event,
+				RuntimeEvent::Referrals(Event::ConversionFailed { asset_id, .. }) if *asset_id == DAI
+			)));
 		});
 }