refactor: LP.borrowerFacet expects Amount, not AmountKWR

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

@@ -161,9 +161,8 @@ export const prepareAdvancerKit = (
             const advanceAmount = feeTools.calculateAdvance(fullAmount);
 
             const { zcfSeat: tmpSeat } = zcf.makeEmptySeatKit();
-            const amountKWR = harden({ USDC: advanceAmount });
             // throws if the pool has insufficient funds
-            borrowerFacet.borrow(tmpSeat, amountKWR);
+            borrowerFacet.borrow(tmpSeat, advanceAmount);
 
             // this cannot throw since `.isSeen()` is called in the same turn
             statusManager.advance(evidence);
@@ -172,7 +171,7 @@ export const prepareAdvancerKit = (
               tmpSeat,
               // @ts-expect-error LocalAccountMethods vs OrchestrationAccount
               poolAccount,
-              amountKWR,
+              harden({ USDC: advanceAmount }),
             );
             void watch(depositV, this.facets.depositHandler, {
               fullAmount,
@@ -230,10 +229,7 @@ export const prepareAdvancerKit = (
           try {
             const { borrowerFacet, notifyFacet } = this.state;
             notifyFacet.notifyAdvancingResult(restCtx, false);
-            borrowerFacet.returnToPool(
-              tmpSeat,
-              harden({ USDC: advanceAmount }),
-            );
+            borrowerFacet.returnToPool(tmpSeat, advanceAmount);
           } catch (e) {
             log('🚨 deposit to localOrchAccount failure recovery failed', e);
           }

packages/fast-usdc/src/exos/liquidity-pool.js

@@ -84,14 +84,8 @@ export const prepareLiquidityPoolKit = (zone, zcf, USDC, tools) => {
     'Liquidity Pool',
     {
       borrower: M.interface('borrower', {
-        borrow: M.call(
-          SeatShape,
-          harden({ USDC: makeNatAmountShape(USDC, 1n) }),
-        ).returns(),
-        returnToPool: M.call(
-          SeatShape,
-          harden({ USDC: makeNatAmountShape(USDC, 1n) }),
-        ).returns(),
+        borrow: M.call(SeatShape, makeNatAmountShape(USDC, 1n)).returns(),
+        returnToPool: M.call(SeatShape, makeNatAmountShape(USDC, 1n)).returns(),
       }),
       repayer: M.interface('repayer', {
         repay: M.call(
@@ -157,22 +151,22 @@ export const prepareLiquidityPoolKit = (zone, zcf, USDC, tools) => {
       borrower: {
         /**
          * @param {ZCFSeat} toSeat
-         * @param {{ USDC: Amount<'nat'>}} amountKWR
+         * @param {Amount<'nat'>} amount
          */
-        borrow(toSeat, amountKWR) {
+        borrow(toSeat, amount) {
           const { encumberedBalance, poolSeat, poolStats } = this.state;
 
           // Validate amount is available in pool
           const post = borrowCalc(
-            amountKWR.USDC,
+            amount,
             poolSeat.getAmountAllocated('USDC', USDC),
             encumberedBalance,
             poolStats,
           );
 
           // COMMIT POINT
           // UNTIL #10684: ability to terminate an incarnation w/o terminating the contract
-          zcf.atomicRearrange(harden([[poolSeat, toSeat, amountKWR]]));
+          zcf.atomicRearrange(harden([[poolSeat, toSeat, { USDC: amount }]]));
 
           Object.assign(this.state, post);
           this.facets.external.publishPoolMetrics();
@@ -181,21 +175,21 @@ export const prepareLiquidityPoolKit = (zone, zcf, USDC, tools) => {
          * If something fails during advance, return funds to the pool.
          *
          * @param {ZCFSeat} borrowSeat
-         * @param {{ USDC: Amount<'nat'>}} amountKWR
+         * @param {Amount<'nat'>} amount
          */
-        returnToPool(borrowSeat, amountKWR) {
+        returnToPool(borrowSeat, amount) {
           const { zcfSeat: repaySeat } = zcf.makeEmptySeatKit();
           const returnAmounts = harden({
-            Principal: amountKWR.USDC,
+            Principal: amount,
             PoolFee: makeEmpty(USDC),
             ContractFee: makeEmpty(USDC),
           });
           const borrowSeatAllocation = borrowSeat.getCurrentAllocation();
-          isGTE(borrowSeatAllocation.USDC, amountKWR.USDC) ||
-            Fail`⚠️ borrowSeatAllocation ${q(borrowSeatAllocation)} less than amountKWR ${q(amountKWR)}`;
+          isGTE(borrowSeatAllocation.USDC, amount) ||
+            Fail`⚠️ borrowSeatAllocation ${q(borrowSeatAllocation)} less than amountKWR ${q(amount)}`;
           // arrange payments in a format repay is expecting
           zcf.atomicRearrange(
-            harden([[borrowSeat, repaySeat, amountKWR, returnAmounts]]),
+            harden([[borrowSeat, repaySeat, { USDC: amount }, returnAmounts]]),
           );
           return this.facets.repayer.repay(repaySeat, returnAmounts);
         },

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

@@ -106,11 +106,11 @@ const createTestExtensions = (t, common: CommonSetup) => {
   } = { borrow: [], returnToPool: [] };
 
   const mockBorrowerF = Far('LiquidityPool Borrow Facet', {
-    borrow: (seat: ZCFSeat, amounts: { USDC: NatAmount }) => {
-      mockBorrowerFacetCalls.borrow.push([seat, amounts]);
+    borrow: (seat: ZCFSeat, amount: NatAmount) => {
+      mockBorrowerFacetCalls.borrow.push([seat, amount]);
     },
-    returnToPool: (seat: ZCFSeat, amounts: { USDC: NatAmount }) => {
-      mockBorrowerFacetCalls.returnToPool.push([seat, amounts]);
+    returnToPool: (seat: ZCFSeat, amount: NatAmount) => {
+      mockBorrowerFacetCalls.returnToPool.push([seat, amount]);
     },
   });
 
@@ -236,9 +236,9 @@ test('updates status to OBSERVED on insufficient pool funds', async t => {
   } = t.context;
 
   const mockBorrowerFacet = Far('LiquidityPool Borrow Facet', {
-    borrow: (seat: ZCFSeat, amounts: { USDC: NatAmount }) => {
+    borrow: (seat: ZCFSeat, amount: NatAmount) => {
       throw new Error(
-        `Cannot borrow. Requested ${q(amounts.USDC)} must be less than pool balance ${q(usdc.make(1n))}.`,
+        `Cannot borrow. Requested ${q(amount)} must be less than pool balance ${q(usdc.make(1n))}.`,
       );
     },
     returnToPool: () => {}, // not expecting this to be called
@@ -460,7 +460,7 @@ test('returns payment to LP if zoeTools.localTransfer fails', async t => {
 
   const expectedArguments = [
     Far('MockZCFSeat', {}),
-    { USDC: usdc.make(146999999n) }, // net of fees
+    usdc.make(146999999n), // net of fees
   ];
 
   t.is(borrow.length, 1, 'borrow is called before zt.localTransfer fails');
@@ -503,12 +503,12 @@ test('alerts if `returnToPool` fallback fails', async t => {
   } = t.context;
 
   const mockBorrowerFacet = Far('LiquidityPool Borrow Facet', {
-    borrow: (seat: ZCFSeat, amounts: { USDC: NatAmount }) => {
+    borrow: (seat: ZCFSeat, amount: NatAmount) => {
       // note: will not be tracked by `inspectBorrowerFacetCalls`
     },
-    returnToPool: (seat: ZCFSeat, amounts: { USDC: NatAmount }) => {
+    returnToPool: (seat: ZCFSeat, amount: NatAmount) => {
       throw new Error(
-        `⚠️ borrowSeatAllocation ${q({ USDC: usdc.make(0n) })} less than amountKWR ${q(amounts)}`,
+        `⚠️ borrowSeatAllocation ${q({ USDC: usdc.make(0n) })} less than amountKWR ${q(amount)}`,
       );
     },
   });
@@ -536,7 +536,7 @@ test('alerts if `returnToPool` fallback fails', async t => {
     [
       '🚨 deposit to localOrchAccount failure recovery failed',
       Error(
-        `⚠️ borrowSeatAllocation ${q({ USDC: usdc.make(0n) })} less than amountKWR ${q({ USDC: usdc.make(146999999n) })}`,
+        `⚠️ borrowSeatAllocation ${q({ USDC: usdc.make(0n) })} less than amountKWR ${q(usdc.make(146999999n))}`,
       ),
     ],
   ]);