From 1b4f248df256d1c50df9c69ffbf0048789c89d95 Mon Sep 17 00:00:00 2001
From: "Mark S. Miller" <erights@gmail.com>
Date: Thu, 18 Jul 2024 15:15:23 -0700
Subject: [PATCH] fix(async-flow): fix endowment equate bug

---
 packages/async-flow/src/equate.js       | 24 ++++++++++++++++--------
 packages/async-flow/test/equate.test.js | 10 +++++-----
 2 files changed, 21 insertions(+), 13 deletions(-)

diff --git a/packages/async-flow/src/equate.js b/packages/async-flow/src/equate.js
index f11df50e911..9bfa3bba4a3 100644
--- a/packages/async-flow/src/equate.js
+++ b/packages/async-flow/src/equate.js
@@ -31,7 +31,14 @@ export const makeEquate = bijection => {
         Fail`unequal ${g} vs ${h}`;
       return;
     }
-    if (bijection.has(g, h)) {
+    if (bijection.hasGuest(g) && bijection.guestToHost(g) === h) {
+      // Note that this can be true even when
+      // `bijection.hostToGuest(h) !== g`
+      // but only when the two guests represent the same host, as
+      // happens with unwrapping. That why we do this one-way test
+      // rather than the two way `bijection.has` test.
+      // Even in this one-way case, we have still satisfied
+      // the equate, so return.
       return;
     }
     const gPassStyle = passStyleOf(g);
@@ -41,7 +48,8 @@ export const makeEquate = bijection => {
       // TODO when we do, delete the `throw Fail` line and uncomment
       // the two lines below it.
       // We *do* support passing a guest wrapper of a hostVow back
-      // to the host, but that would be cause by `bijection.has` above.
+      // to the host, but that would be caught by `bijection.guestToHost`
+      // test above.
       throw Fail`guest promises not yet passable`;
       // `init` does not yet do enough checking anyway. For this case,
       // we should ensure that h is a host wrapper of a guest promise,
@@ -92,10 +100,10 @@ export const makeEquate = bijection => {
       case 'remotable': {
         // Note that we can send a guest wrapping of a host remotable
         // back to the host,
-        // but that should have already been taken care of by the
-        // `bijection.has` above.
+        // but that should have already been caught by the
+        // `bijection.guestToHost` above.
         throw Fail`cannot yet send guest remotables to host ${g} vs ${h}`;
-        // `init` does not yet do enough checking anyway. For this case,
+        // `unwrapInit` does not yet do enough checking anyway. For this case,
         // we should ensure that h is a host wrapper of a guest remotable,
         // which is a wrapping we don't yet support.
         // bijection.unwrapInit(g, h);
@@ -104,10 +112,10 @@ export const makeEquate = bijection => {
       case 'promise': {
         // Note that we can send a guest wrapping of a host promise
         // (or vow) back to the host,
-        // but that should have already been taken care of by the
-        // `bijection.has` above.
+        // but that should have already been caught by the
+        // `bijection.guestToHost` above.
         throw Fail`cannot yet send guest promises to host ${g} vs ${h}`;
-        // `init` does not yet do enough checking anyway. For this case,
+        // `unwrapInit` does not yet do enough checking anyway. For this case,
         // we should ensure that h is a host wrapper of a guest promise,
         // which is a wrapping we don't yet support.
         // bijection.unwrapInit(g, h);
diff --git a/packages/async-flow/test/equate.test.js b/packages/async-flow/test/equate.test.js
index 5be4100794e..1ae04e08fe6 100644
--- a/packages/async-flow/test/equate.test.js
+++ b/packages/async-flow/test/equate.test.js
@@ -57,24 +57,24 @@ const testEquate = (t, zone, showOnConsole = false) => {
   bij.unwrapInit(g1, h1);
   t.notThrows(() => equate(g1, h1));
   t.throws(() => equate(g1, h2), {
-    message: 'internal: g->h "[Alleged: g1]" -> "[Vow]" vs "[Alleged: h1]"',
+    message: 'unequal passStyles "remotable" vs "tagged"',
   });
   t.throws(() => equate(g2, h1), {
-    message: 'internal: unexpected h->g "[Alleged: h1]" -> "[Alleged: g1]"',
+    message: 'unequal passStyles "promise" vs "remotable"',
   });
   bij.unwrapInit(g2, h2);
   equate(g2, h2);
 
   t.throws(() => equate(g1, h2), {
-    message: 'internal: g->h "[Alleged: g1]" -> "[Vow]" vs "[Alleged: h1]"',
+    message: 'unequal passStyles "remotable" vs "tagged"',
   });
   t.throws(() => equate(g2, h1), {
-    message: 'internal: g->h "[Promise]" -> "[Alleged: h1]" vs "[Vow]"',
+    message: 'unequal passStyles "promise" vs "remotable"',
   });
 
   equate(harden([g1, g2]), harden([h1, h2]));
   t.throws(() => equate(harden([g1, g2]), harden([h1, h1])), {
-    message: '[1]: internal: g->h "[Promise]" -> "[Alleged: h1]" vs "[Vow]"',
+    message: '[1]: unequal passStyles "promise" vs "remotable"',
   });
 
   const gErr1 = harden(makeError(X`error ${'redacted message'}`, URIError));