Fix issue 785. For-in now works on strings: for (var i in "asdf") now works

all the time, not just the first time it is run.
Review URL: http://codereview.chromium.org/3037008

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5095 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/handles.cc

@@ -664,8 +664,12 @@ Handle<FixedArray> GetKeysInFixedArrayFor(Handle<JSObject> object,
     // therefore it does not make sense to cache the property names
     // for arguments objects.  Arguments objects will always have
     // elements.
+    // Wrapped strings have elements, but don't have an elements
+    // array or dictionary.  So the fast inline test for whether to
+    // use the cache says yes, so we should not create a cache.
     bool cache_enum_keys =
         ((current->map()->constructor() != *arguments_function) &&
+         !current->IsJSValue() &&
          !current->IsAccessCheckNeeded() &&
          !current->HasNamedInterceptor() &&
          !current->HasIndexedInterceptor());

test/mjsunit/for-in-special-cases.js

@@ -62,3 +62,60 @@ for (var j = 0; j < 10; ++j) {
 assertEquals(10, i);
 assertEquals(10, j);
 
+
+function Accumulate(x) {
+  var accumulator = "";
+  for (var i in x) {
+    accumulator += i;
+  }
+  return accumulator;
+}
+
+for (var i = 0; i < 3; ++i) {
+  var elements = Accumulate("abcd");
+  // We do not assume that for-in enumerates elements in order.
+  assertTrue(-1 != elements.indexOf("0"));
+  assertTrue(-1 != elements.indexOf("1"));
+  assertTrue(-1 != elements.indexOf("2"));
+  assertTrue(-1 != elements.indexOf("3"));
+  assertEquals(4, elements.length);
+}
+
+function for_in_string_prototype() {
+
+  var x = new String("abc");
+  x.foo = 19;
+  function B() {
+    this.bar = 5;
+    this[7] = 4;
+  }
+  B.prototype = x;
+
+  var y = new B();
+  y.gub = 13;
+
+  var elements = Accumulate(y);
+  var elements1 = Accumulate(y);
+  // If for-in returns elements in a different order on multiple calls, this
+  // assert will fail.  If that happens, consider if that behavior is OK.
+  assertEquals(elements, elements1, "For-in elements not the same both times.");
+  // We do not assume that for-in enumerates elements in order.
+  assertTrue(-1 != elements.indexOf("0"));
+  assertTrue(-1 != elements.indexOf("1"));
+  assertTrue(-1 != elements.indexOf("2"));
+  assertTrue(-1 != elements.indexOf("7"));
+  assertTrue(-1 != elements.indexOf("foo"));
+  assertTrue(-1 != elements.indexOf("bar"));
+  assertTrue(-1 != elements.indexOf("gub"));
+  assertEquals(13, elements.length);
+
+  elements = Accumulate(x);
+  assertTrue(-1 != elements.indexOf("0"));
+  assertTrue(-1 != elements.indexOf("1"));
+  assertTrue(-1 != elements.indexOf("2"));
+  assertTrue(-1 != elements.indexOf("foo"));
+  assertEquals(6, elements.length);
+}
+
+for_in_string_prototype();
+for_in_string_prototype();