[GR-17733] custom list subclassing with list.__init__ call

PullRequest: graalpython/621

Author: cosminbasca

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

@@ -1,4 +1,4 @@
-# Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
+# Copyright (c) 2018, 2019, Oracle and/or its affiliates. All rights reserved.
 # DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 #
 # The Universal Permissive License (UPL), Version 1.0
@@ -62,3 +62,19 @@ def __iter__(self):
 
     l = list(ListSubclass([1, 2, 3, 4]))
     assert l == [10, 20, 30, 40], "was: {!s}".format(l)
+
+
+def test_list_init_call():
+    class MyList(list):
+        def __init__(self, a, b=None):
+            if b:
+                list.__init__(self, [b])
+            else:
+                list.__init__(self, [a])
+
+    l = MyList(10)
+    assert l == [10]
+    l = MyList(10, 20)
+    assert l == [20]
+    l = MyList(10, b=30)
+    assert l == [30]

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/modules/BuiltinConstructors.java

@@ -1444,18 +1444,19 @@ public boolean bool(VirtualFrame frame, Object cls, Object obj,
     }
 
     // list([iterable])
-    @Builtin(name = LIST, minNumOfPositionalArgs = 1, maxNumOfPositionalArgs = 2, constructsClass = PythonBuiltinClassType.PList)
+    @Builtin(name = LIST, minNumOfPositionalArgs = 1, takesVarArgs = true, takesVarKeywordArgs = true, constructsClass = PythonBuiltinClassType.PList)
     @GenerateNodeFactory
-    public abstract static class ListNode extends PythonBinaryBuiltinNode {
+    public abstract static class ListNode extends PythonVarargsBuiltinNode {
         @Specialization
-        protected PList constructList(LazyPythonClass cls, @SuppressWarnings("unused") Object value) {
+        protected PList constructList(LazyPythonClass cls, @SuppressWarnings("unused") Object[] arguments, @SuppressWarnings("unused") PKeyword[] keywords) {
             return factory().createList(cls);
         }
 
         @Fallback
-        public PList listObject(@SuppressWarnings("unused") Object cls, Object arg) {
+        @SuppressWarnings("unused")
+        public PList listObject(Object cls, Object[] arguments, PKeyword[] keywords) {
             CompilerAsserts.neverPartOfCompilation();
-            throw new RuntimeException("list does not support iterable object " + arg);
+            throw raise(PythonBuiltinClassType.TypeError, "'cls' is not a type object (%p)", cls);
         }
     }