From c70b8a10b04c5554b1a952daa584216227858bc5 Mon Sep 17 00:00:00 2001
From: Michael FIG <mfig@agoric.com>
Date: Tue, 17 Mar 2020 13:37:35 -0600
Subject: [PATCH] fix: improve command device support

Propagate inboundHandler errors better.  Prevent asynchronous
rejection errors.
---
 packages/SwingSet/src/devices/command-src.js  |  6 +++++-
 packages/cosmic-swingset/lib/ag-solo/start.js | 13 +++++++++++--
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/packages/SwingSet/src/devices/command-src.js b/packages/SwingSet/src/devices/command-src.js
index 9080a29d049..3665b2bef83 100644
--- a/packages/SwingSet/src/devices/command-src.js
+++ b/packages/SwingSet/src/devices/command-src.js
@@ -21,7 +21,7 @@ export default function setup(syscall, state, helpers, endowments) {
         const body = JSON.parse(`${bodyString}`);
         SO(inboundHandler).inbound(Nat(count), body);
       } catch (e) {
-        console.log(`error during inboundCallback: ${e}`);
+        console.log(`error during inboundCallback`, e);
         throw new Error(`error during inboundCallback: ${e}`);
       }
     });
@@ -33,6 +33,10 @@ export default function setup(syscall, state, helpers, endowments) {
       },
 
       sendResponse(count, isReject, obj) {
+        if (isReject && obj instanceof Error) {
+          console.log('inboundHandler rejected with:', obj);
+          obj = { message: obj.message };
+        }
         try {
           deliverResponse(count, isReject, JSON.stringify(obj));
         } catch (e) {
diff --git a/packages/cosmic-swingset/lib/ag-solo/start.js b/packages/cosmic-swingset/lib/ag-solo/start.js
index c3941b6de6d..2520903a3c7 100644
--- a/packages/cosmic-swingset/lib/ag-solo/start.js
+++ b/packages/cosmic-swingset/lib/ag-solo/start.js
@@ -137,10 +137,19 @@ async function buildSwingset(
     // this promise could take an arbitrarily long time to resolve, so don't
     // wait on it
     const p = cm.inboundCommand(obj);
+
+    // Register a handler so that we don't get complaints about
+    // asynchronously-handled callbacks.
+    p.catch(_ => {});
+
     // TODO: synchronize this somehow, make sure it doesn't overlap with the
-    // processKernel() call in deliverInbound()
+    // processKernel() call in deliverInboundToMbx()
     await processKernel();
-    return p;
+
+    // Rethrow any exception so that our caller must handle it.
+    return p.catch(e => {
+      throw e;
+    });
   }
 
   const intervalMillis = 1200;