related reflect bug: make copies of big values
so that callers cannot edit large values inside interfaces.
R=r
DELTA=52 (42 added, 1 deleted, 9 changed)
OCL=29180
CL=29195
diff --git a/src/lib/reflect/all_test.go b/src/lib/reflect/all_test.go
index c473fe3..903b0f5 100644
--- a/src/lib/reflect/all_test.go
+++ b/src/lib/reflect/all_test.go
@@ -583,3 +583,31 @@
t.Errorf("Interface() on interface: ", v, s.w);
}
}
+
+func TestInterfaceEditing(t *testing.T) {
+ // strings are bigger than one word,
+ // so the interface conversion allocates
+ // memory to hold a string and puts that
+ // pointer in the interface.
+ var i interface{} = "hello";
+
+ // if i pass the interface value by value
+ // to NewValue, i should get a fresh copy
+ // of the value.
+ v := NewValue(i);
+
+ // and setting that copy to "bye" should
+ // not change the value stored in i.
+ v.(StringValue).Set("bye");
+ if i.(string) != "hello" {
+ t.Errorf(`Set("bye") changed i to %s`, i.(string));
+ }
+
+ // the same should be true of smaller items.
+ i = 123;
+ v = NewValue(i);
+ v.(IntValue).Set(234);
+ if i.(int) != 123 {
+ t.Errorf("Set(234) changed i to %d", i.(int));
+ }
+}
