Correcting guards for creating new tuple.

Author: ppisl

graalpython/com.oracle.graal.python.test/src/tests/test_tuple.py

@@ -254,6 +254,27 @@ def __iter__(self):
         self.assertFalse(m is tm)
         self.assertFalse(m is mm)
 
+    def test_creating_tuple(self):
+        class MyTuple(tuple):
+            pass
+
+        def maketuple(t):
+            return tuple(t)
+
+        a = MyTuple((1,2))
+        b = tuple(a)
+        self.assertFalse(a is b)
+
+        b = MyTuple(a)
+        self.assertFalse(a is b)
+
+        b = tuple((1,2))
+        self.assertFalse(maketuple(a) is maketuple(b))
+        self.assertTrue(maketuple(b) is maketuple(b))
+        self.assertTrue(tuple(b) is b)
+        self.assertFalse(tuple(a) is a)
+        
+
 class TupleCompareTest(CompareTest):
 
     def test_compare(self):

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/nodes/builtins/TupleNodes.java

@@ -102,7 +102,7 @@ public PTuple tuple(@SuppressWarnings("unused") PythonClass cls, PTuple iterable
             return iterable;
         }
 
-        @Specialization(guards = "!isNoValue(iterable)")
+        @Specialization(guards = {"createNewTuple(cls, iterable)"})
         public PTuple tuple(PythonClass cls, Object iterable,
                         @Cached("create()") GetIteratorNode getIterator,
                         @Cached("create()") GetNextNode next,
@@ -126,6 +126,13 @@ public PTuple tuple(@SuppressWarnings("unused") Object cls, Object value) {
             throw new RuntimeException("list does not support iterable object " + value);
         }
 
+        protected boolean createNewTuple(PythonClass cls, Object iterable) {
+            if (iterable instanceof PTuple) {
+                return !(PGuards.cannotBeOverridden(cls) && PGuards.cannotBeOverridden(getClass(iterable)));
+            }
+            return true;
+        }
+
         public static ConstructTupleNode create() {
             return TupleNodesFactory.ConstructTupleNodeGen.create();
         }