[GR-64163] Fix __new__ lookup for custom metatypes.

PullRequest: graalpython/4534

Author: steve-s

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

@@ -1,4 +1,4 @@
-# Copyright (c) 2020, 2025, Oracle and/or its affiliates. All rights reserved.
+# Copyright (c) 2020, 2026, 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
@@ -117,10 +117,54 @@ class notAMeta(metaclass=Meta):
         pass
     notAMeta2 = type("notAMeta2", (notAMeta,), {})
 
-    # the below assertions should pass, but this is such an unusual case that we
-    # ignore this.
-    # assert notAMeta.metatype is NewDescriptor
-    # assert notAMeta2.metatype is NewDescriptor
+    assert notAMeta.metatype is NewDescriptor
+    assert notAMeta2.metatype is NewDescriptor
+
+
+def test_meta_new_default_metatype():
+    class Meta(type):
+        def __new__(*args, **kwargs):
+            cls = type.__new__(*args, **kwargs)
+            cls.metatype = "meta"
+            return cls
+
+    class uses_meta(metaclass=Meta):
+        pass
+
+    uses_meta2 = type("uses_meta2", (uses_meta,), {})
+
+    assert uses_meta.metatype == "meta"
+    assert uses_meta2.metatype == "meta"
+
+
+def test_meta_meta_new_custom_getattribute():
+    meta_new_calls = []
+
+    class MetaMeta(type):
+        def __getattribute__(self, name):
+            if name == "__new__":
+                def new(*args, **kwargs):
+                    cls = type.__new__(*args, **kwargs)
+                    cls.metatype = "getattribute"
+                    return cls
+                return new
+            return super().__getattribute__(name)
+
+    class Meta(type, metaclass=MetaMeta):
+        def __new__(*args, **kwargs):
+            meta_new_calls.append(True)
+            cls = type.__new__(*args, **kwargs)
+            cls.metatype = "meta"
+            return cls
+
+    class uses_getattribute(metaclass=Meta):
+        pass
+
+    uses_getattribute2 = type("uses_getattribute2", (uses_getattribute,), {})
+
+    assert uses_getattribute.metatype == "getattribute"
+    assert uses_getattribute2.metatype == "getattribute"
+    assert meta_new_calls == []
 
 
 def test_subclasses_collection():

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/type/slots/TpSlotVarargs.java

@@ -82,6 +82,7 @@
 import com.oracle.graal.python.builtins.objects.type.slots.TpSlotVarargsFactory.CallSlotTpCallNodeGen;
 import com.oracle.graal.python.builtins.objects.type.slots.TpSlotVarargsFactory.CallSlotTpInitNodeGen;
 import com.oracle.graal.python.builtins.objects.type.slots.TpSlotVarargsFactory.CallSlotTpNewNodeGen;
+import com.oracle.graal.python.lib.PyObjectGetAttr;
 import com.oracle.graal.python.nodes.ErrorMessages;
 import com.oracle.graal.python.nodes.PGuards;
 import com.oracle.graal.python.nodes.PRaiseNode;
@@ -97,6 +98,7 @@
 import com.oracle.graal.python.nodes.function.builtins.PythonTernaryBuiltinNode;
 import com.oracle.graal.python.nodes.function.builtins.PythonUnaryBuiltinNode;
 import com.oracle.graal.python.nodes.function.builtins.PythonVarargsBuiltinNode;
+import com.oracle.graal.python.nodes.object.GetClassNode;
 import com.oracle.graal.python.runtime.IndirectCallData.BoundaryCallData;
 import com.oracle.graal.python.runtime.PythonContext;
 import com.oracle.graal.python.runtime.PythonContext.GetThreadStateNode;
@@ -110,6 +112,7 @@
 import com.oracle.truffle.api.Truffle;
 import com.oracle.truffle.api.dsl.Bind;
 import com.oracle.truffle.api.dsl.Cached;
+import com.oracle.truffle.api.dsl.Cached.Exclusive;
 import com.oracle.truffle.api.dsl.Fallback;
 import com.oracle.truffle.api.dsl.GenerateCached;
 import com.oracle.truffle.api.dsl.GenerateInline;
@@ -484,14 +487,27 @@ public static Object executeUncached(TpSlot slot, Object self, Object[] args, PK
             return CallSlotTpNewNodeGen.getUncached().execute(null, null, slot, self, args, keywords);
         }
 
-        @Specialization
-        static Object callPython(VirtualFrame frame, Node inliningTarget, TpSlotPythonSingle slot, Object self, Object[] args, PKeyword[] keywords,
+        @Specialization(guards = "hasDefaultMetatype(inliningTarget, self, getClassNode)", limit = "1")
+        static Object callPythonFast(VirtualFrame frame, Node inliningTarget, TpSlotPythonSingle slot, Object self, Object[] args, PKeyword[] keywords,
+                        @Cached GetClassNode getClassNode,
                         @Cached BindNewMethodNode bindNew,
-                        @Cached(inline = false) CallNode callNode) {
+                        @Exclusive @Cached(inline = false) CallNode callNode) {
             Object callable = bindNew.execute(frame, inliningTarget, slot.getCallable(), self);
             return callNode.execute(frame, callable, PythonUtils.prependArgument(self, args), keywords);
         }
 
+        @Specialization(replaces = "callPythonFast")
+        static Object callPython(VirtualFrame frame, Node inliningTarget, @SuppressWarnings("unused") TpSlotPythonSingle slot, Object self, Object[] args, PKeyword[] keywords,
+                        @Cached PyObjectGetAttr getNew,
+                        @Exclusive @Cached(inline = false) CallNode callNode) {
+            Object callable = getNew.execute(frame, inliningTarget, self, T___NEW__);
+            return callNode.execute(frame, callable, PythonUtils.prependArgument(self, args), keywords);
+        }
+
+        static boolean hasDefaultMetatype(Node inliningTarget, Object self, GetClassNode getClassNode) {
+            return getClassNode.execute(inliningTarget, self) == PythonBuiltinClassType.PythonClass;
+        }
+
         @Specialization
         @InliningCutoff
         static Object callNative(VirtualFrame frame, TpSlotCExtNative slot, Object self, Object[] args, PKeyword[] keywords,