[GR-27300] Backport a fix in TopScopeObject.

PullRequest: js/1747

Author: gilles-duboscq

graal-js/src/com.oracle.truffle.js.test/src/com/oracle/truffle/js/test/polyglot/JavaScriptLanguageTest.java

@@ -41,6 +41,7 @@
 package com.oracle.truffle.js.test.polyglot;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 
 import java.util.Collections;
@@ -160,4 +161,18 @@ public String toString() {
             return "string";
         }
     }
+
+    @Test
+    public void testRemoveBindings() {
+        try (Context context = JSTest.newContextBuilder().build()) {
+            Value bindings = context.getBindings("js");
+            assertTrue(bindings.removeMember("eval"));
+
+            assertFalse(bindings.hasMember("foo"));
+            context.eval(JavaScriptLanguage.ID, "foo=42;");
+            assertTrue(bindings.hasMember("foo"));
+            assertTrue(bindings.removeMember("foo"));
+            assertFalse(bindings.hasMember("foo"));
+        }
+    }
 }

graal-js/src/com.oracle.truffle.js/src/com/oracle/truffle/js/runtime/interop/TopScopeObject.java

@@ -266,7 +266,7 @@ boolean isMemberRemovable(String member,
     void removeMember(String member,
                     @Shared("interop") @CachedLibrary(limit = "LIMIT") InteropLibrary interop) throws UnsupportedMessageException, UnknownIdentifierException {
         int length = NAMES.length;
-        for (int i = 0; i < length; i++) {
+        for (int i = scopeIndex; i < length; i++) {
             Object scope = this.objects[i];
             if (interop.isMemberRemovable(scope, member)) {
                 interop.removeMember(scope, member);