prevent calling run more than once; fixes #1992

1 files changed, 3 insertions, 4 deletions

diff --git a/src/postamble.js b/src/postamble.js
index 63495914..d6c059b8 100644
--- a/src/postamble.js
+++ b/src/postamble.js
@@ -117,16 +117,15 @@ function run(args) {
 
   preRun();
 
-  if (runDependencies > 0) {
-    // a preRun added a dependency, run will be called later
-    return;
-  }
+  if (runDependencies > 0) return; // a preRun added a dependency, run will be called later
+  if (Module['calledRun']) return; // run may have just been called through dependencies being fulfilled just in this very frame
 
   function doRun() {
     ensureInitRuntime();
 
     preMain();
 
+    assert(!Module['calledRun']);
     Module['calledRun'] = true;
     if (Module['_main'] && shouldRunNow) {
       Module['callMain'](args);