Add assets in pool with native to query_acceptable_payment_assets's return

cumulus/parachains/runtimes/assets/asset-hub-rococo/src/lib.rs

@@ -1326,7 +1326,23 @@ impl_runtime_apis! {
 
 	impl xcm_runtime_apis::fees::XcmPaymentApi<Block> for Runtime {
 		fn query_acceptable_payment_assets(xcm_version: xcm::Version) -> Result<Vec<VersionedAssetId>, XcmPaymentApiError> {
-			let acceptable_assets = vec![AssetId(xcm_config::TokenLocation::get())];
+			let native_token = xcm_config::TokenLocation::get();
+			// We accept the native token to pay fees.
+			let mut acceptable_assets = vec![AssetId(native_token.clone())];
+			// We also accept all assets in a pool with the native token.
+			acceptable_assets.extend(
+				pallet_asset_conversion::Pools::<Runtime>::iter_keys().filter_map(
+					|(asset_1, asset_2)| {
+						if asset_1 == native_token {
+							Some(asset_2.clone().into())
+						} else if asset_2 == native_token {
+							Some(asset_1.clone().into())
+						} else {
+							None
+						}
+					},
+				),
+			);
 			PolkadotXcm::query_acceptable_payment_assets(xcm_version, acceptable_assets)
 		}
 

cumulus/parachains/runtimes/assets/asset-hub-westend/src/lib.rs

@@ -1357,7 +1357,17 @@ impl_runtime_apis! {
 
 	impl xcm_runtime_apis::fees::XcmPaymentApi<Block> for Runtime {
 		fn query_acceptable_payment_assets(xcm_version: xcm::Version) -> Result<Vec<VersionedAssetId>, XcmPaymentApiError> {
-			let acceptable_assets = vec![AssetId(xcm_config::WestendLocation::get())];
+			// We accept the native token (`xcm_config::WestendLocation`) to pay fees.
+			let mut acceptable_assets = vec![AssetId(xcm_config::WestendLocation::get())];
+			// We also accept all assets in a pool with the native token.
+			let keys_iter = pallet_asset_conversion::Pools::<Runtime>::iter_keys();
+			for (asset_1, asset_2) in keys_iter {
+				if asset_1 == xcm_config::WestendLocation::get() {
+					acceptable_assets.push(asset_2.clone().into());
+				} else if asset_2 == xcm_config::WestendLocation::get() {
+					acceptable_assets.push(asset_1.clone().into());
+				}
+			}
 			PolkadotXcm::query_acceptable_payment_assets(xcm_version, acceptable_assets)
 		}
 

prdoc/pr_5599.prdoc

@@ -0,0 +1,19 @@
+# Schema: Polkadot SDK PRDoc Schema (prdoc) v1.0.0
+# See doc at https://raw.githubusercontent.com/paritytech/polkadot-sdk/master/prdoc/schema_user.json
+
+title: Add assets in pool with native to query_acceptable_payment_assets
+
+doc:
+  - audience: Runtime Dev
+    description: |
+      The `XcmPaymentApi::query_acceptable_payment_assets` API can be used to get a list of all
+      the assets that can be used for fee payment.
+      This is usually just the native asset, but the asset hubs have the asset conversion pallet.
+      In the case of the asset hubs, this list now includes all assets in a liquidity pool with
+      the native one.
+
+crates:
+  - name: asset-hub-rococo-runtime
+    bump: minor
+  - name: asset-hub-westend-runtime
+    bump: minor