From 7ae15ed39fa83b3974b3ee8e74ff17be5bc35dfb Mon Sep 17 00:00:00 2001
From: "Mark S. Miller" <erights@gmail.com>
Date: Wed, 7 Aug 2024 15:28:55 -0700
Subject: [PATCH] fixup! restore previous buggy behavior with better error

---
 packages/vats/src/virtual-purse.js | 20 +++++++-
 packages/vats/test/vpurse.test.js  | 80 ++++++++++++++++++++++++++++++
 2 files changed, 99 insertions(+), 1 deletion(-)

diff --git a/packages/vats/src/virtual-purse.js b/packages/vats/src/virtual-purse.js
index 8b8ac1ff9150..155f29e31a92 100644
--- a/packages/vats/src/virtual-purse.js
+++ b/packages/vats/src/virtual-purse.js
@@ -1,7 +1,7 @@
 import { Fail } from '@endo/errors';
 import { E } from '@endo/far';
 import { isPromise } from '@endo/promise-kit';
-import { getInterfaceGuardPayload } from '@endo/patterns';
+import { getInterfaceGuardPayload, matches } from '@endo/patterns';
 
 import { M } from '@agoric/store';
 import {
@@ -105,6 +105,22 @@ export const makeVirtualPurseKitIKit = (
  *   current balance iterable for a given brand.
  */
 
+/**
+ * Until https://github.com/Agoric/agoric-sdk/issues/9407 is fixed, this
+ * function restricts the `optAmountShape`, if provided, to be a concrete
+ * `Amount` rather than a `Pattern` as it is supposed to be.
+ *
+ * TODO: Once https://github.com/Agoric/agoric-sdk/issues/9407 is fixed, remove
+ * this function and all calls to it.
+ *
+ * @param {Pattern} [optAmountShape]
+ */
+const legacyRestrictAmountShapeArg = optAmountShape => {
+  if (optAmountShape && !matches(optAmountShape, AmountShape)) {
+    throw Fail`optAmountShape if provided, must still be a concrete Amount due to https://github.com/Agoric/agoric-sdk/issues/9407`;
+  }
+};
+
 /** @param {import('@agoric/zone').Zone} zone */
 const prepareVirtualPurseKit = zone =>
   zone.exoClassKit(
@@ -142,6 +158,7 @@ const prepareVirtualPurseKit = zone =>
          * @returns {Promise<Payment<'nat'>>}
          */
         async recoverableClaim(payment, optAmountShape) {
+          legacyRestrictAmountShapeArg(optAmountShape);
           const {
             state: { recoveryPurse },
           } = this;
@@ -169,6 +186,7 @@ const prepareVirtualPurseKit = zone =>
       minter: {
         /** @type {Retain} */
         async retain(payment, optAmountShape) {
+          legacyRestrictAmountShapeArg(optAmountShape);
           !!this.state.mint || Fail`minter cannot retain without a mint.`;
           return E(this.state.issuer).burn(payment, optAmountShape);
         },
diff --git a/packages/vats/test/vpurse.test.js b/packages/vats/test/vpurse.test.js
index 4e7572660d88..ca0da5744ea5 100644
--- a/packages/vats/test/vpurse.test.js
+++ b/packages/vats/test/vpurse.test.js
@@ -169,6 +169,86 @@ test('makeVirtualPurse', async t => {
     );
   };
 
+  expected.pushAmount(fungible837);
+  await E(vpurse)
+    .deposit(payment, fungible837)
+    .then(checkDeposit)
+    .then(performWithdrawal)
+    .then(checkWithdrawal);
+});
+
+// TODO Once https://github.com/Agoric/agoric-sdk/issues/9407 is fixed,
+// This test should replace the similar one above.
+test.failing('makeVirtualPurse with optAmountShape pattern', async t => {
+  t.plan(22);
+  const { baggage } = t.context;
+  const zone = makeDurableZone(baggage).subZone('makeVirtualPurse');
+
+  const { expected, balanceUpdater, issuer, mint, brand, vpurse } = setup(
+    t,
+    zone,
+  );
+
+  const payment = mint.mintPayment(AmountMath.make(brand, 837n));
+
+  const notifier = E(vpurse).getCurrentAmountNotifier();
+  let nextUpdateP = E(notifier).getUpdateSince();
+
+  const checkNotifier = async () => {
+    const { value: balance, updateCount } = await nextUpdateP;
+    t.assert(
+      AmountMath.isEqual(await E(vpurse).getCurrentAmount(), balance),
+      `the notifier balance is the same as the purse`,
+    );
+    nextUpdateP = E(notifier).getUpdateSince(updateCount);
+  };
+
+  balanceUpdater.updateState(AmountMath.makeEmpty(brand));
+  await checkNotifier();
+  t.assert(
+    AmountMath.isEqual(
+      await E(vpurse).getCurrentAmount(),
+      AmountMath.makeEmpty(brand),
+    ),
+    `empty purse is empty`,
+  );
+  t.is(await E(vpurse).getAllegedBrand(), brand, `purse's brand is correct`);
+  const fungible837 = AmountMath.make(brand, 837n);
+
+  const checkDeposit = async newPurseBalance => {
+    t.assert(
+      AmountMath.isEqual(newPurseBalance, fungible837),
+      `the amount returned is the payment amount`,
+    );
+    await checkNotifier();
+    t.assert(
+      AmountMath.isEqual(await E(vpurse).getCurrentAmount(), fungible837),
+      `the new purse balance is the payment's old balance`,
+    );
+  };
+
+  const performWithdrawal = () => {
+    expected.pullAmount(fungible837);
+    return E(vpurse).withdraw(fungible837);
+  };
+
+  const checkWithdrawal = async newPayment => {
+    await issuer.getAmountOf(newPayment).then(amount => {
+      t.assert(
+        AmountMath.isEqual(amount, fungible837),
+        `the withdrawn payment has the right balance`,
+      );
+    });
+    await checkNotifier();
+    t.assert(
+      AmountMath.isEqual(
+        await E(vpurse).getCurrentAmount(),
+        AmountMath.makeEmpty(brand),
+      ),
+      `the purse is empty again`,
+    );
+  };
+
   expected.pushAmount(fungible837);
   await E(vpurse)
     .deposit(payment, M.and(fungible837))