diff --git a/bridges/snowbridge/pallets/inbound-queue/src/test.rs b/bridges/snowbridge/pallets/inbound-queue/src/test.rs
index bd993c968df7373910b438a2e090ef2896bb41dd..41c38460aabf1c796d743f0ee9de135d3c9e9ef0 100644
--- a/bridges/snowbridge/pallets/inbound-queue/src/test.rs
+++ b/bridges/snowbridge/pallets/inbound-queue/src/test.rs
@@ -40,8 +40,8 @@ fn test_submit_happy_path() {
.into(),
nonce: 1,
message_id: [
- 57, 61, 232, 3, 66, 61, 25, 190, 234, 188, 193, 174, 13, 186, 1, 64, 237, 94, 73,
- 83, 14, 18, 209, 213, 78, 121, 43, 108, 251, 245, 107, 67,
+ 255, 125, 48, 71, 174, 185, 100, 26, 159, 43, 108, 6, 116, 218, 55, 155, 223, 143,
+ 141, 22, 124, 110, 241, 18, 122, 217, 130, 29, 139, 76, 97, 201,
],
fee_burned: 110000000000,
}
diff --git a/bridges/snowbridge/primitives/router/src/inbound/mod.rs b/bridges/snowbridge/primitives/router/src/inbound/mod.rs
index 5cff8413af66b23fe55fc6c68f8b936768289ce9..a10884b455316834774edbca6a69edf6e3f3ec30 100644
--- a/bridges/snowbridge/primitives/router/src/inbound/mod.rs
+++ b/bridges/snowbridge/primitives/router/src/inbound/mod.rs
@@ -249,7 +249,7 @@ impl<
let total_amount = fee + CreateAssetDeposit::get();
let total: Asset = (Location::parent(), total_amount).into();
- let bridge_location: Location = (Parent, Parent, GlobalConsensus(network)).into();
+ let bridge_location = Location::new(2, GlobalConsensus(network));
let owner = GlobalConsensusEthereumConvertsFor::<[u8; 32]>::from_chain_id(&chain_id);
let asset_id = Self::convert_token_address(network, token);
@@ -262,8 +262,15 @@ impl<
// Pay for execution.
BuyExecution { fees: xcm_fee, weight_limit: Unlimited },
// Fund the snowbridge sovereign with the required deposit for creation.
- DepositAsset { assets: Definite(deposit.into()), beneficiary: bridge_location },
- // Only our inbound-queue pallet is allowed to invoke `UniversalOrigin`
+ DepositAsset { assets: Definite(deposit.into()), beneficiary: bridge_location.clone() },
+ // This `SetAppendix` ensures that `xcm_fee` not spent by `Transact` will be
+ // deposited to snowbridge sovereign, instead of being trapped, regardless of
+ // `Transact` success or not.
+ SetAppendix(Xcm(vec![
+ RefundSurplus,
+ DepositAsset { assets: AllCounted(1).into(), beneficiary: bridge_location },
+ ])),
+ // Only our inbound-queue pallet is allowed to invoke `UniversalOrigin`.
DescendOrigin(PalletInstance(inbound_queue_pallet_index).into()),
// Change origin to the bridge.
UniversalOrigin(GlobalConsensus(network)),
@@ -280,12 +287,10 @@ impl<
.encode()
.into(),
},
- RefundSurplus,
- // Clear the origin so that remaining assets in holding
- // are claimable by the physical origin (BridgeHub)
- ClearOrigin,
// Forward message id to Asset Hub
SetTopic(message_id.into()),
+ // Once the program ends here, appendix program will run, which will deposit any
+ // leftover fee to snowbridge sovereign.
]
.into();
@@ -340,17 +345,24 @@ impl<
match dest_para_id {
Some(dest_para_id) => {
let dest_para_fee_asset: Asset = (Location::parent(), dest_para_fee).into();
+ let bridge_location = Location::new(2, GlobalConsensus(network));
instructions.extend(vec![
+ // After program finishes deposit any leftover assets to the snowbridge
+ // sovereign.
+ SetAppendix(Xcm(vec![DepositAsset {
+ assets: Wild(AllCounted(2)),
+ beneficiary: bridge_location,
+ }])),
// Perform a deposit reserve to send to destination chain.
DepositReserveAsset {
- assets: Definite(vec![dest_para_fee_asset.clone(), asset.clone()].into()),
+ assets: Definite(vec![dest_para_fee_asset.clone(), asset].into()),
dest: Location::new(1, [Parachain(dest_para_id)]),
xcm: vec![
// Buy execution on target.
BuyExecution { fees: dest_para_fee_asset, weight_limit: Unlimited },
- // Deposit asset to beneficiary.
- DepositAsset { assets: Definite(asset.into()), beneficiary },
+ // Deposit assets to beneficiary.
+ DepositAsset { assets: Wild(AllCounted(2)), beneficiary },
// Forward message id to destination parachain.
SetTopic(message_id.into()),
]
@@ -371,6 +383,8 @@ impl<
// Forward message id to Asset Hub.
instructions.push(SetTopic(message_id.into()));
+ // The `instructions` to forward to AssetHub, and the `total_fees` to locally burn (since
+ // they are teleported within `instructions`).
(instructions.into(), total_fees.into())
}
diff --git a/cumulus/parachains/integration-tests/emulated/tests/bridges/bridge-hub-rococo/src/lib.rs b/cumulus/parachains/integration-tests/emulated/tests/bridges/bridge-hub-rococo/src/lib.rs
index ac08e48ded68dacad27756ff62b55caf6a1a7f32..9d54d431e83916d68805eeb5a99a5fc70240ad9c 100644
--- a/cumulus/parachains/integration-tests/emulated/tests/bridges/bridge-hub-rococo/src/lib.rs
+++ b/cumulus/parachains/integration-tests/emulated/tests/bridges/bridge-hub-rococo/src/lib.rs
@@ -55,9 +55,12 @@ mod imports {
BridgeHubRococoXcmConfig, EthereumBeaconClient, EthereumInboundQueue,
},
penpal_emulated_chain::{
- penpal_runtime::xcm_config::{
- CustomizableAssetFromSystemAssetHub as PenpalCustomizableAssetFromSystemAssetHub,
- UniversalLocation as PenpalUniversalLocation,
+ penpal_runtime::{
+ self,
+ xcm_config::{
+ CustomizableAssetFromSystemAssetHub as PenpalCustomizableAssetFromSystemAssetHub,
+ UniversalLocation as PenpalUniversalLocation,
+ },
},
PenpalAParaPallet as PenpalAPallet, PenpalAssetOwner,
},
@@ -72,9 +75,8 @@ mod imports {
BridgeHubRococoParaReceiver as BridgeHubRococoReceiver,
BridgeHubRococoParaSender as BridgeHubRococoSender,
BridgeHubWestendPara as BridgeHubWestend, PenpalAPara as PenpalA,
- PenpalAParaReceiver as PenpalAReceiver, PenpalAParaSender as PenpalASender,
- RococoRelay as Rococo, RococoRelayReceiver as RococoReceiver,
- RococoRelaySender as RococoSender,
+ PenpalAParaSender as PenpalASender, RococoRelay as Rococo,
+ RococoRelayReceiver as RococoReceiver, RococoRelaySender as RococoSender,
};
pub const ASSET_MIN_BALANCE: u128 = 1000;
diff --git a/cumulus/parachains/integration-tests/emulated/tests/bridges/bridge-hub-rococo/src/tests/snowbridge.rs b/cumulus/parachains/integration-tests/emulated/tests/bridges/bridge-hub-rococo/src/tests/snowbridge.rs
index 84328fb7c6d201b86edf9aba954d84b7598e3005..d91a0c6895f98c377230f48d984d393e9773aeb9 100644
--- a/cumulus/parachains/integration-tests/emulated/tests/bridges/bridge-hub-rococo/src/tests/snowbridge.rs
+++ b/cumulus/parachains/integration-tests/emulated/tests/bridges/bridge-hub-rococo/src/tests/snowbridge.rs
@@ -286,11 +286,19 @@ fn send_token_from_ethereum_to_penpal() {
// Fund AssetHub sovereign account so it can pay execution fees for the asset transfer
BridgeHubRococo::fund_accounts(vec![(asset_hub_sovereign.clone(), INITIAL_FUND)]);
- // Fund PenPal sender and receiver
- PenpalA::fund_accounts(vec![
- (PenpalAReceiver::get(), INITIAL_FUND),
- (PenpalASender::get(), INITIAL_FUND),
- ]);
+ // Fund PenPal receiver (covering ED)
+ let native_id: Location = Parent.into();
+ let receiver: AccountId = [
+ 28, 189, 45, 67, 83, 10, 68, 112, 90, 208, 136, 175, 49, 62, 24, 248, 11, 83, 239, 22, 179,
+ 97, 119, 205, 75, 119, 184, 70, 242, 165, 240, 124,
+ ]
+ .into();
+ PenpalA::mint_foreign_asset(
+ <PenpalA as Chain>::RuntimeOrigin::signed(PenpalAssetOwner::get()),
+ native_id,
+ receiver,
+ penpal_runtime::EXISTENTIAL_DEPOSIT,
+ );
PenpalA::execute_with(|| {
assert_ok!(<PenpalA as Chain>::System::set_storage(
diff --git a/prdoc/pr_5563.prdoc b/prdoc/pr_5563.prdoc
new file mode 100644
index 0000000000000000000000000000000000000000..cbf436125bb5e1125dae8340963721eb314a1392
--- /dev/null
+++ b/prdoc/pr_5563.prdoc
@@ -0,0 +1,14 @@
+title: "snowbridge: improve destination fee handling to avoid trapping fees dust"
+
+doc:
+ - audience: Runtime User
+ description: |
+ On Ethereum -> Polkadot Asset Hub messages, whether they are a token transfer
+ or a `Transact` for registering a new token, any unspent fees are deposited to
+ Snowbridge's sovereign account on Asset Hub, rather than trapped in AH's asset trap.
+
+crates:
+ - name: snowbridge-router-primitives
+ bump: patch
+ - name: snowbridge-pallet-inbound-queue
+ bump: patch