module: fix cyclical dynamic import

ensures that instantiation result is only used during initial loading PR-URL: #18965 Reviewed-By: Gus Caplan <me@gus.host> Reviewed-By: Guy Bedford <guybedford@gmail.com> Reviewed-By: Colin Ihrig <cjihrig@gmail.com> Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com> Reviewed-By: Jan Krems <jan.krems@gmail.com> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
nodejs · vsemozhetbyt · Feb 21, 2018 · Feb 22, 2018 · Feb 22, 2018 · Mar 2, 2018
commit a3b95428d5d1113bcc548b5a46700cc57239158d
diff --git a/lib/internal/loader/ModuleJob.js b/lib/internal/loader/ModuleJob.js
@@ -50,10 +50,11 @@ class ModuleJob {
   }
 
   async instantiate() {
-    if (this.instantiated) {
-      return this.instantiated;
+    if (!this.instantiated) {
+      return this.instantiated = this._instantiate();
     }
-    return this.instantiated = this._instantiate();
+    await this.instantiated;
+    return this.module;
   }
 
   // This method instantiates the module associated with this job and its

diff --git a/test/es-module/test-esm-cyclic-dynamic-import.mjs b/test/es-module/test-esm-cyclic-dynamic-import.mjs
@@ -0,0 +1,3 @@
+// Flags: --experimental-modules
+import '../common';
+import('./test-esm-cyclic-dynamic-import');