Fix shadowing of internal module, exports and require when a global counterpart exists

@see jhnns/rewire-webpack#6

Author: jhnns

lib/getImportGlobalsSrc.js

@@ -16,6 +16,10 @@ function getImportGlobalsSrc(ignore) {
     ignore = ignore || [];
     // global itself can't be overridden because it's the only reference to our real global objects
     ignore.push("global");
+    // ignore 'module', 'exports' and 'require' on the global scope, because otherwise our code would
+    // shadow the module-internal variables
+    // @see https://github.com/jhnns/rewire-webpack/pull/6
+    ignore.push("module", "exports", "require");
 
     for (key in globalObj) { /* jshint forin: false */
         if (ignore.indexOf(key) !== -1) {

test/getImportGlobalsSrc.test.js

@@ -7,11 +7,24 @@ describe("getImportGlobalsSrc", function () {
         var context = {
                 global: global
             },
+            expectedGlobals,
             src,
-            actualGlobals,
-            expectedGlobals = Object.keys(global);
+            actualGlobals;
+
+        // Temporarily set module-internal variables on the global scope to check if getImportGlobalsSrc()
+        // ignores them properly
+        global.module = module;
+        global.exports = exports;
+        global.require = require;
 
         src = getImportGlobalsSrc();
+
+        delete global.module;
+        delete global.exports;
+        delete global.require;
+
+        expectedGlobals = Object.keys(global);
+
         vm.runInNewContext(src, context);
         actualGlobals = Object.keys(context).filter(function (key) {
             // node v0.10 does not set a constructor property on the context