Fixed class inheritance null type descriptor issue #753

Author: Victor R. Escobar

setup.py

@@ -11,7 +11,7 @@ def read (*paths):
 
 setup (
 	name = 'Transcrypt',
-	version = '3.7.16',
+	version = '3.7.17',
 	description = 'Python to JavaScript transpiler, supporting multiple inheritance and generating lean, highly readable code',
 	long_description = (
 		read ('README.rst')

transcrypt/modules/org/transcrypt/__core__.js

@@ -180,11 +180,11 @@ export var py_metatype = {
         for (var index = bases.length - 1; index >= 0; index--) {   // Reversed order, since class vars of first base should win
             var base = bases [index];
             for (var attrib in base) {
-                var descrip = Object.getOwnPropertyDescriptor (base, attrib);
+                var descrip = Object.getOwnPropertyDescriptor (base, attrib) || {};
                 Object.defineProperty (cls, attrib, descrip);
             }           
             for (let symbol of Object.getOwnPropertySymbols (base)) {
-                let descrip = Object.getOwnPropertyDescriptor (base, symbol);
+                let descrip = Object.getOwnPropertyDescriptor (base, symbol) || {};
                 Object.defineProperty (cls, symbol, descrip);
             }
         }
@@ -196,11 +196,11 @@ export var py_metatype = {
 
         // Add own methods, properties and own static attributes to the created cls object
         for (var attrib in attribs) {
-            var descrip = Object.getOwnPropertyDescriptor (attribs, attrib);
+            var descrip = Object.getOwnPropertyDescriptor (attribs, attrib) || {}; // As the descriptor can be undefined
             Object.defineProperty (cls, attrib, descrip);
         }
         for (let symbol of Object.getOwnPropertySymbols (attribs)) {
-            let descrip = Object.getOwnPropertyDescriptor (attribs, symbol);
+            let descrip = Object.getOwnPropertyDescriptor (attribs, symbol) || {};
             Object.defineProperty (cls, symbol, descrip);
         }
 

transcrypt/modules/org/transcrypt/__envir__.js

@@ -1,4 +1,4 @@
 __envir__.interpreter_name = 'python';
 __envir__.transpiler_name = 'transcrypt';
 __envir__.executor_name = __envir__.transpiler_name;
-__envir__.transpiler_version = '3.7.16';
+__envir__.transpiler_version = '3.7.17';