feat(fast-usdc): settler handles OBSERVED tx

Author: dckc

packages/fast-usdc/src/exos/settler.js

@@ -1,15 +1,17 @@
+import { AmountMath } from '@agoric/ertp';
 import { assertAllDefined, makeTracer } from '@agoric/internal';
 import { atob } from '@endo/base64';
 import { makeError, q } from '@endo/errors';
+import { E } from '@endo/far';
 import { M } from '@endo/patterns';
 
-import { AmountMath } from '@agoric/ertp';
+import { PendingTxStatus } from '../constants.js';
 import { addressTools } from '../utils/address.js';
 import { makeFeeTools } from '../utils/fees.js';
 
 /**
  * @import {FungibleTokenPacketData} from '@agoric/cosmic-proto/ibc/applications/transfer/v2/packet.js';
- * @import {Denom, OrchestrationAccount, LocalAccountMethods} from '@agoric/orchestration';
+ * @import {Denom, OrchestrationAccount, LocalAccountMethods, ChainHub} from '@agoric/orchestration';
  * @import {WithdrawToSeat} from '@agoric/orchestration/src/utils/zoe-tools'
  * @import {IBCChannelID, VTransferIBCEvent} from '@agoric/vats';
  * @import {Zone} from '@agoric/zone';
@@ -30,17 +32,21 @@ const trace = makeTracer('Settler');
  * @param {FeeConfig} caps.feeConfig
  * @param {HostOf<WithdrawToSeat>} caps.withdrawToSeat
  * @param {import('@agoric/vow').VowTools} caps.vowTools
+ * @param {ChainHub} caps.chainHub
  */
 export const prepareSettler = (
   zone,
-  { statusManager, USDC, zcf, feeConfig, withdrawToSeat, vowTools },
+  { statusManager, USDC, zcf, feeConfig, withdrawToSeat, vowTools, chainHub },
 ) => {
   assertAllDefined({ statusManager });
   return zone.exoClass(
     'Fast USDC Settler',
     M.interface('SettlerI', {
       monitorTransfers: M.callWhen().returns(M.any()),
       receiveUpcall: M.call(M.record()).returns(M.promise()),
+      settleSansFees: M.call(M.string(), M.string(), M.nat()).returns(
+        M.promise(),
+      ),
     }),
     /**
      * @param {{
@@ -111,6 +117,11 @@ export const prepareSettler = (
           );
         }
 
+        const pending = statusManager.lookupPending(sender, amountInt);
+        if (pending.find(it => it.status === PendingTxStatus.Observed)) {
+          return this.self.settleSansFees(sender, EUD, amountInt);
+        }
+
         // Disperse funds
 
         const { repayer, settlementAccount } = this.state;
@@ -137,10 +148,25 @@ export const prepareSettler = (
         repayer.repay(settlingSeat, split);
 
         // update status manager, marking tx `SETTLED`
-        statusManager.settle(
-          /** @type {NobleAddress} */ (tx.sender),
-          amountInt,
+        statusManager.settle(sender, amountInt);
+      },
+      /**
+       * @param {NobleAddress} sender
+       * @param {string} EUD
+       * @param {bigint} amountInt
+       */
+      async settleSansFees(sender, EUD, amountInt) {
+        const { settlementAccount } = this.state;
+
+        const dest = chainHub.makeChainAddress(EUD);
+
+        const txfrV = E(settlementAccount).transfer(
+          dest,
+          AmountMath.make(USDC, amountInt),
         );
+        await vowTools.when(txfrV); // TODO: watch, handle failure
+
+        statusManager.settle(sender, amountInt);
       },
     },
     {

packages/fast-usdc/test/exos/settler.test.ts

@@ -64,13 +64,17 @@ const makeTestContext = async t => {
     return vowTools.asVow(() => {});
   };
 
+  const { chainHub } = common.facadeServices;
+  chainHub.registerChain('dydx', fetchedChainInfo.dydx);
+  chainHub.registerChain('osmosis', fetchedChainInfo.osmosis);
   const makeSettler = prepareSettler(zone.subZone('settler'), {
     statusManager,
     USDC: usdc.brand,
     zcf,
     withdrawToSeat: mockWithdrawToSeat,
     feeConfig: common.commonPrivateArgs.feeConfig,
     vowTools: common.bootstrap.vowTools,
+    chainHub,
   });
 
   const defaultSettlerParams = harden({
@@ -126,7 +130,7 @@ const makeTestContext = async t => {
 
 const test = anyTest as TestFn<Awaited<ReturnType<typeof makeTestContext>>>;
 
-test.before(async t => (t.context = await makeTestContext(t)));
+test.beforeEach(async t => (t.context = await makeTestContext(t)));
 
 test('happy path: disburse to LPs; StatusManager removes tx', async t => {
   const {
@@ -218,6 +222,65 @@ test('happy path: disburse to LPs; StatusManager removes tx', async t => {
   // TODO, confirm vstorage write for TxStatus.SETTLED
 });
 
+test('slow path: disburse to LPs; StatusManager removes tx', async t => {
+  const {
+    common,
+    makeSettler,
+    statusManager,
+    defaultSettlerParams,
+    repayer,
+    simulate,
+    accounts,
+    peekCalls,
+  } = t.context;
+  const { usdc } = common.brands;
+  const { feeConfig } = common.commonPrivateArgs;
+
+  const settler = makeSettler({
+    repayer,
+    settlementAccount: accounts.settlement.account,
+    ...defaultSettlerParams,
+  });
+
+  const cctpTxEvidence = simulate.observe();
+  t.deepEqual(
+    statusManager.lookupPending(
+      cctpTxEvidence.tx.forwardingAddress,
+      cctpTxEvidence.tx.amount,
+    ),
+    [{ ...cctpTxEvidence, status: PendingTxStatus.Observed }],
+    'statusManager shows this tx is only observed',
+  );
+
+  t.log('Simulate incoming IBC settlement');
+  void settler.receiveUpcall(MockVTransferEvents.AGORIC_PLUS_OSMO());
+  await eventLoopIteration();
+
+  t.log('review settler interactions with other components');
+  t.deepEqual(peekCalls(), []);
+  t.deepEqual(accounts.settlement.callLog, [
+    [
+      'transfer',
+      {
+        chainId: 'osmosis-1',
+        encoding: 'bech32',
+        value: 'osmo183dejcnmkka5dzcu9xw6mywq0p2m5peks28men',
+      },
+      usdc.units(150),
+    ],
+  ]);
+
+  t.deepEqual(
+    statusManager.lookupPending(
+      cctpTxEvidence.tx.forwardingAddress,
+      cctpTxEvidence.tx.amount,
+    ),
+    [],
+    'SETTLED entry removed from StatusManger',
+  );
+  // TODO, confirm vstorage write for TxStatus.SETTLED
+});
+
 test.todo("StatusManager does not receive update when we can't settle");
 
 test.todo('Observed -> Settle flow');

packages/fast-usdc/test/mocks.ts

@@ -44,9 +44,10 @@ export const prepareMockOrchAccounts = (
     OrchestrationAccount<{ chainId: 'agoric' }>
   >;
 
+  const settlementCallLog = [] as any[];
   const settlementAccountMock = zone.exo('Mock Settlement Account', undefined, {
-    someMethod() {
-      throw Error('todo');
+    transfer(...args) {
+      settlementCallLog.push(harden(['transfer', ...args]));
     },
   });
   const settlementAccount = settlementAccountMock as unknown as HostInterface<
@@ -59,6 +60,7 @@ export const prepareMockOrchAccounts = (
     },
     settlement: {
       account: settlementAccount,
+      callLog: settlementCallLog,
     },
   };
 };