From 4cdbb26f57d37dc06fe789936b63bf65a19acb88 Mon Sep 17 00:00:00 2001
From: Christopher Willis-Ford <cwillisf@media.mit.edu>
Date: Wed, 3 Apr 2019 11:01:00 -0700
Subject: [PATCH] Explicitly check that every extension block has an opcode

---
 src/extension-support/extension-manager.js | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/extension-support/extension-manager.js b/src/extension-support/extension-manager.js
index 30bc6d50d..d3ced5df1 100644
--- a/src/extension-support/extension-manager.js
+++ b/src/extension-support/extension-manager.js
@@ -390,6 +390,10 @@ class ExtensionManager {
             }
             break;
         default:
+            if (!blockInfo.opcode) {
+                throw new Error('Missing opcode for block');
+            }
+
             blockInfo.func = blockInfo.func ? this._sanitizeID(blockInfo.func) : blockInfo.opcode;
 
             // Avoid promise overhead if possible