From 0fd6f30b9b50800d1d9ff32cac76ff9fb8c75408 Mon Sep 17 00:00:00 2001
From: Michael FIG <michael+github@fig.org>
Date: Tue, 15 Oct 2019 12:14:08 -0600
Subject: [PATCH] fix(captp): be sure to bind the questionID, promiseID

By using lastPromiseID directly, it could be incremented before the
promise actually resolves, which results in an incorrect message.
---
 lib/captp.js | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/lib/captp.js b/lib/captp.js
index 0991e0abc6e..d380c50b881 100644
--- a/lib/captp.js
+++ b/lib/captp.js
@@ -29,18 +29,19 @@ export default function makeCapTP(ourId, send, bootstrapObj = undefined) {
         // new export
         if (Promise.resolve(val) === val) {
           lastPromiseID += 1;
-          slot = `p${lastPromiseID}`;
+          const promiseID = lastPromiseID;
+          slot = `p${promiseID}`;
           val.then(
             res =>
               send({
                 type: 'CTP_RESOLVE',
-                promiseID: lastPromiseID,
+                promiseID,
                 res: serialize(harden(res)),
               }),
             rej =>
               send({
                 type: 'CTP_RESOLVE',
-                promiseID: lastPromiseID,
+                promiseID,
                 rej: serialize(harden(rej)),
               }),
           );
@@ -80,10 +81,11 @@ export default function makeCapTP(ourId, send, bootstrapObj = undefined) {
             pr.rej = reject;
           });
           lastQuestionID += 1;
-          questions.set(lastQuestionID, pr);
+          const questionID = lastQuestionID;
+          questions.set(questionID, pr);
           send({
             type: 'CTP_CALL',
-            questionID: lastQuestionID,
+            questionID,
             target: slot,
             method: serialize(harden([prop, args])),
           });
@@ -184,10 +186,11 @@ export default function makeCapTP(ourId, send, bootstrapObj = undefined) {
       pr.rej = reject;
     });
     lastQuestionID += 1;
-    questions.set(lastQuestionID, pr);
+    const questionID = lastQuestionID;
+    questions.set(questionID, pr);
     send({
       type: 'CTP_BOOTSTRAP',
-      questionID: lastQuestionID,
+      questionID,
     });
     return harden(pr.p);
   };