From 37e67cc89910110a7087c5fe66a93af9bc336893 Mon Sep 17 00:00:00 2001
From: Yurii Karabas <1998uriyyo@gmail.com>
Date: Sun, 17 Apr 2022 11:17:25 +0300
Subject: [PATCH 1/7] gh-91603: Speed up isinstance/issubclass on union types

---
 Include/internal/pycore_unionobject.h         |  1 +
 ...2-04-17-11-03-45.gh-issue-91603.hYw1Lv.rst |  2 +
 Objects/abstract.c                            | 12 +++
 Objects/unionobject.c                         | 74 ++++---------------
 4 files changed, 28 insertions(+), 61 deletions(-)
 create mode 100644 Misc/NEWS.d/next/Core and Builtins/2022-04-17-11-03-45.gh-issue-91603.hYw1Lv.rst

diff --git a/Include/internal/pycore_unionobject.h b/Include/internal/pycore_unionobject.h
index 9962f57610387d..6f4f1be04eac0c 100644
--- a/Include/internal/pycore_unionobject.h
+++ b/Include/internal/pycore_unionobject.h
@@ -15,6 +15,7 @@ extern PyObject *_Py_union_type_or(PyObject *, PyObject *);
 #define _PyGenericAlias_Check(op) PyObject_TypeCheck(op, &Py_GenericAliasType)
 extern PyObject *_Py_subs_parameters(PyObject *, PyObject *, PyObject *, PyObject *);
 extern PyObject *_Py_make_parameters(PyObject *);
+extern PyObject *_Py_union_args_for_check(PyObject *, bool);
 
 #ifdef __cplusplus
 }
diff --git a/Misc/NEWS.d/next/Core and Builtins/2022-04-17-11-03-45.gh-issue-91603.hYw1Lv.rst b/Misc/NEWS.d/next/Core and Builtins/2022-04-17-11-03-45.gh-issue-91603.hYw1Lv.rst
new file mode 100644
index 00000000000000..042482ad06c37c
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2022-04-17-11-03-45.gh-issue-91603.hYw1Lv.rst	
@@ -0,0 +1,2 @@
+Speed-up ``isinstance`` and ``issubclass`` checks for ``types.UnionType``.
+Patch provided by Yurii Karabas.
diff --git a/Objects/abstract.c b/Objects/abstract.c
index 79f5a5f760f8e2..14d71fb4e0bbb9 100644
--- a/Objects/abstract.c
+++ b/Objects/abstract.c
@@ -2625,6 +2625,12 @@ object_recursive_isinstance(PyThreadState *tstate, PyObject *inst, PyObject *cls
         return object_isinstance(inst, cls);
     }
 
+    if (_PyUnion_Check(cls)) {
+        cls = _Py_union_args_for_check(cls, true);
+        if (!cls)
+            return -1;
+    }
+
     if (PyTuple_Check(cls)) {
         /* Not a general sequence -- that opens up the road to
            recursion and stack overflow. */
@@ -2714,6 +2720,12 @@ object_issubclass(PyThreadState *tstate, PyObject *derived, PyObject *cls)
         return recursive_issubclass(derived, cls);
     }
 
+    if (_PyUnion_Check(cls)) {
+        cls = _Py_union_args_for_check(cls, false);
+        if (!cls)
+            return -1;
+    }
+
     if (PyTuple_Check(cls)) {
 
         if (_Py_EnterRecursiveCall(tstate, " in __subclasscheck__")) {
diff --git a/Objects/unionobject.c b/Objects/unionobject.c
index 72a0a3f2cf8d22..98daac03c95554 100644
--- a/Objects/unionobject.c
+++ b/Objects/unionobject.c
@@ -61,60 +61,6 @@ is_generic_alias_in_args(PyObject *args)
     return 1;
 }
 
-static PyObject *
-union_instancecheck(PyObject *self, PyObject *instance)
-{
-    unionobject *alias = (unionobject *) self;
-    Py_ssize_t nargs = PyTuple_GET_SIZE(alias->args);
-    if (!is_generic_alias_in_args(alias->args)) {
-        PyErr_SetString(PyExc_TypeError,
-            "isinstance() argument 2 cannot contain a parameterized generic");
-        return NULL;
-    }
-    for (Py_ssize_t iarg = 0; iarg < nargs; iarg++) {
-        PyObject *arg = PyTuple_GET_ITEM(alias->args, iarg);
-        if (PyType_Check(arg)) {
-            int res = PyObject_IsInstance(instance, arg);
-            if (res < 0) {
-                return NULL;
-            }
-            if (res) {
-                Py_RETURN_TRUE;
-            }
-        }
-    }
-    Py_RETURN_FALSE;
-}
-
-static PyObject *
-union_subclasscheck(PyObject *self, PyObject *instance)
-{
-    if (!PyType_Check(instance)) {
-        PyErr_SetString(PyExc_TypeError, "issubclass() arg 1 must be a class");
-        return NULL;
-    }
-    unionobject *alias = (unionobject *)self;
-    if (!is_generic_alias_in_args(alias->args)) {
-        PyErr_SetString(PyExc_TypeError,
-            "issubclass() argument 2 cannot contain a parameterized generic");
-        return NULL;
-    }
-    Py_ssize_t nargs = PyTuple_GET_SIZE(alias->args);
-    for (Py_ssize_t iarg = 0; iarg < nargs; iarg++) {
-        PyObject *arg = PyTuple_GET_ITEM(alias->args, iarg);
-        if (PyType_Check(arg)) {
-            int res = PyObject_IsSubclass(instance, arg);
-            if (res < 0) {
-                return NULL;
-            }
-            if (res) {
-                Py_RETURN_TRUE;
-            }
-        }
-    }
-    Py_RETURN_FALSE;
-}
-
 static PyObject *
 union_richcompare(PyObject *a, PyObject *b, int op)
 {
@@ -348,12 +294,6 @@ static PyMemberDef union_members[] = {
         {0}
 };
 
-static PyMethodDef union_methods[] = {
-        {"__instancecheck__", union_instancecheck, METH_O},
-        {"__subclasscheck__", union_subclasscheck, METH_O},
-        {0}};
-
-
 static PyObject *
 union_getitem(PyObject *self, PyObject *item)
 {
@@ -440,6 +380,19 @@ union_getattro(PyObject *self, PyObject *name)
     return PyObject_GenericGetAttr(self, name);
 }
 
+PyObject *
+_Py_union_args_for_check(PyObject *self, bool is_instance_check)
+{
+    PyObject *args = ((unionobject *) self)->args;
+    if (!is_generic_alias_in_args(args)) {
+        PyErr_Format(PyExc_TypeError,
+                     "%s() argument 2 cannot contain a parameterized generic",
+                     is_instance_check ? "isinstance" : "issubclass");
+        return NULL;
+    }
+    return args;
+}
+
 PyTypeObject _PyUnion_Type = {
     PyVarObject_HEAD_INIT(&PyType_Type, 0)
     .tp_name = "types.UnionType",
@@ -455,7 +408,6 @@ PyTypeObject _PyUnion_Type = {
     .tp_hash = union_hash,
     .tp_getattro = union_getattro,
     .tp_members = union_members,
-    .tp_methods = union_methods,
     .tp_richcompare = union_richcompare,
     .tp_as_mapping = &union_as_mapping,
     .tp_as_number = &union_as_number,

From bd2688445825cd91795ee95d986106325f77d694 Mon Sep 17 00:00:00 2001
From: Yurii Karabas <1998uriyyo@gmail.com>
Date: Sun, 17 Apr 2022 18:07:57 +0300
Subject: [PATCH 2/7] Unify logic for tuple and types.UnionType checks

---
 Doc/library/functions.rst             |  3 ++-
 Include/internal/pycore_unionobject.h |  2 +-
 Lib/test/test_types.py                |  4 ++--
 Objects/abstract.c                    | 14 ++++----------
 Objects/unionobject.c                 | 24 ++----------------------
 5 files changed, 11 insertions(+), 36 deletions(-)

diff --git a/Doc/library/functions.rst b/Doc/library/functions.rst
index eaa4d482ce3fc9..4ab33945bbbb25 100644
--- a/Doc/library/functions.rst
+++ b/Doc/library/functions.rst
@@ -905,7 +905,8 @@ are always available.  They are listed here in alphabetical order.
    tuples) or a :ref:`types-union` of multiple types, return ``True`` if
    *object* is an instance of any of the types.
    If *classinfo* is not a type or tuple of types and such tuples,
-   a :exc:`TypeError` exception is raised.
+   a :exc:`TypeError` exception is raised. :exc:`TypeError` may not be
+   raised for an invalid type if an earlier check succeeds.
 
    .. versionchanged:: 3.10
       *classinfo* can be a :ref:`types-union`.
diff --git a/Include/internal/pycore_unionobject.h b/Include/internal/pycore_unionobject.h
index 6f4f1be04eac0c..a9ed5651a410e8 100644
--- a/Include/internal/pycore_unionobject.h
+++ b/Include/internal/pycore_unionobject.h
@@ -15,7 +15,7 @@ extern PyObject *_Py_union_type_or(PyObject *, PyObject *);
 #define _PyGenericAlias_Check(op) PyObject_TypeCheck(op, &Py_GenericAliasType)
 extern PyObject *_Py_subs_parameters(PyObject *, PyObject *, PyObject *, PyObject *);
 extern PyObject *_Py_make_parameters(PyObject *);
-extern PyObject *_Py_union_args_for_check(PyObject *, bool);
+extern PyObject *_Py_union_args(PyObject *self);
 
 #ifdef __cplusplus
 }
diff --git a/Lib/test/test_types.py b/Lib/test/test_types.py
index 42fd4f56235fab..3cc24af4980643 100644
--- a/Lib/test/test_types.py
+++ b/Lib/test/test_types.py
@@ -951,8 +951,8 @@ def __eq__(self, other):
         with self.assertRaises(ZeroDivisionError):
             list[int] | list[bt]
 
-        union_ga = (int | list[str], int | collections.abc.Callable[..., str],
-                    int | d)
+        union_ga = (list[str] | int, collections.abc.Callable[..., str] | int,
+                    d | int)
         # Raise error when isinstance(type, type | genericalias)
         for type_ in union_ga:
             with self.subTest(f"check isinstance/issubclass is invalid for {type_}"):
diff --git a/Objects/abstract.c b/Objects/abstract.c
index 14d71fb4e0bbb9..a219ee1d747f66 100644
--- a/Objects/abstract.c
+++ b/Objects/abstract.c
@@ -2625,11 +2625,8 @@ object_recursive_isinstance(PyThreadState *tstate, PyObject *inst, PyObject *cls
         return object_isinstance(inst, cls);
     }
 
-    if (_PyUnion_Check(cls)) {
-        cls = _Py_union_args_for_check(cls, true);
-        if (!cls)
-            return -1;
-    }
+    if (_PyUnion_Check(cls))
+        cls = _Py_union_args(cls);
 
     if (PyTuple_Check(cls)) {
         /* Not a general sequence -- that opens up the road to
@@ -2720,11 +2717,8 @@ object_issubclass(PyThreadState *tstate, PyObject *derived, PyObject *cls)
         return recursive_issubclass(derived, cls);
     }
 
-    if (_PyUnion_Check(cls)) {
-        cls = _Py_union_args_for_check(cls, false);
-        if (!cls)
-            return -1;
-    }
+    if (_PyUnion_Check(cls))
+        cls = _Py_union_args(cls);
 
     if (PyTuple_Check(cls)) {
 
diff --git a/Objects/unionobject.c b/Objects/unionobject.c
index 98daac03c95554..a1f6cb86c6cbc0 100644
--- a/Objects/unionobject.c
+++ b/Objects/unionobject.c
@@ -48,19 +48,6 @@ union_hash(PyObject *self)
     return hash;
 }
 
-static int
-is_generic_alias_in_args(PyObject *args)
-{
-    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
-    for (Py_ssize_t iarg = 0; iarg < nargs; iarg++) {
-        PyObject *arg = PyTuple_GET_ITEM(args, iarg);
-        if (_PyGenericAlias_Check(arg)) {
-            return 0;
-        }
-    }
-    return 1;
-}
-
 static PyObject *
 union_richcompare(PyObject *a, PyObject *b, int op)
 {
@@ -381,16 +368,9 @@ union_getattro(PyObject *self, PyObject *name)
 }
 
 PyObject *
-_Py_union_args_for_check(PyObject *self, bool is_instance_check)
+_Py_union_args(PyObject *self)
 {
-    PyObject *args = ((unionobject *) self)->args;
-    if (!is_generic_alias_in_args(args)) {
-        PyErr_Format(PyExc_TypeError,
-                     "%s() argument 2 cannot contain a parameterized generic",
-                     is_instance_check ? "isinstance" : "issubclass");
-        return NULL;
-    }
-    return args;
+    return ((unionobject *) self)->args;
 }
 
 PyTypeObject _PyUnion_Type = {

From 55af5a6adfdce1ec7f636dc5cff8567201db859b Mon Sep 17 00:00:00 2001
From: Yurii Karabas <1998uriyyo@gmail.com>
Date: Sun, 17 Apr 2022 18:31:37 +0300
Subject: [PATCH 3/7] Fix test_isinstance_with_or_union

---
 Lib/test/test_isinstance.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Lib/test/test_isinstance.py b/Lib/test/test_isinstance.py
index 9d37cff9903385..a0974640bc1146 100644
--- a/Lib/test/test_isinstance.py
+++ b/Lib/test/test_isinstance.py
@@ -225,7 +225,7 @@ def test_isinstance_with_or_union(self):
         with self.assertRaises(TypeError):
             isinstance(2, list[int] | int)
         with self.assertRaises(TypeError):
-            isinstance(2, int | str | list[int] | float)
+            isinstance(2, float | str | list[int] | int)
 
 
 

From cbd44cc14e96d33868c38a676e0ce08395f03614 Mon Sep 17 00:00:00 2001
From: Yurii Karabas <1998uriyyo@gmail.com>
Date: Sun, 17 Apr 2022 23:40:37 +0300
Subject: [PATCH 4/7] Update Misc/NEWS.d/next/Core and
 Builtins/2022-04-17-11-03-45.gh-issue-91603.hYw1Lv.rst

Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com>
---
 .../2022-04-17-11-03-45.gh-issue-91603.hYw1Lv.rst             | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Misc/NEWS.d/next/Core and Builtins/2022-04-17-11-03-45.gh-issue-91603.hYw1Lv.rst b/Misc/NEWS.d/next/Core and Builtins/2022-04-17-11-03-45.gh-issue-91603.hYw1Lv.rst
index 042482ad06c37c..957bd5ea09b58a 100644
--- a/Misc/NEWS.d/next/Core and Builtins/2022-04-17-11-03-45.gh-issue-91603.hYw1Lv.rst	
+++ b/Misc/NEWS.d/next/Core and Builtins/2022-04-17-11-03-45.gh-issue-91603.hYw1Lv.rst	
@@ -1,2 +1,2 @@
-Speed-up ``isinstance`` and ``issubclass`` checks for ``types.UnionType``.
-Patch provided by Yurii Karabas.
+Speed up :func:`isinstance` and :func:`issubclass` checks for :class:`types.UnionType`.
+Patch by Yurii Karabas.

From cc1cb4095947aad0afe78c8e8abb3c9ae6543c32 Mon Sep 17 00:00:00 2001
From: Yurii Karabas <1998uriyyo@gmail.com>
Date: Tue, 19 Apr 2022 10:27:34 +0300
Subject: [PATCH 5/7] Update Lib/test/test_types.py

Co-authored-by: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
---
 Lib/test/test_types.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Lib/test/test_types.py b/Lib/test/test_types.py
index 3cc24af4980643..cde9dadc5e97fa 100644
--- a/Lib/test/test_types.py
+++ b/Lib/test/test_types.py
@@ -953,7 +953,7 @@ def __eq__(self, other):
 
         union_ga = (list[str] | int, collections.abc.Callable[..., str] | int,
                     d | int)
-        # Raise error when isinstance(type, type | genericalias)
+        # Raise error when isinstance(type, genericalias | type)
         for type_ in union_ga:
             with self.subTest(f"check isinstance/issubclass is invalid for {type_}"):
                 with self.assertRaises(TypeError):

From 1514cdfeb6efff6f205a47bdd3f0ab94a066387a Mon Sep 17 00:00:00 2001
From: Yurii Karabas <1998uriyyo@gmail.com>
Date: Mon, 25 Apr 2022 10:02:24 +0300
Subject: [PATCH 6/7] Update Objects/unionobject.c

Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com>
---
 Objects/unionobject.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Objects/unionobject.c b/Objects/unionobject.c
index a1f6cb86c6cbc0..88eb6e36f08875 100644
--- a/Objects/unionobject.c
+++ b/Objects/unionobject.c
@@ -370,6 +370,7 @@ union_getattro(PyObject *self, PyObject *name)
 PyObject *
 _Py_union_args(PyObject *self)
 {
+    assert(_PyUnion_Check(self));
     return ((unionobject *) self)->args;
 }
 

From 20c44f81686683abd08b582fecdaf0f596c79397 Mon Sep 17 00:00:00 2001
From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Mon, 25 Apr 2022 06:25:18 -0700
Subject: [PATCH 7/7] Add braces

---
 Objects/abstract.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/Objects/abstract.c b/Objects/abstract.c
index a219ee1d747f66..cfb0edcab0e5d3 100644
--- a/Objects/abstract.c
+++ b/Objects/abstract.c
@@ -2625,8 +2625,9 @@ object_recursive_isinstance(PyThreadState *tstate, PyObject *inst, PyObject *cls
         return object_isinstance(inst, cls);
     }
 
-    if (_PyUnion_Check(cls))
+    if (_PyUnion_Check(cls)) {
         cls = _Py_union_args(cls);
+    }
 
     if (PyTuple_Check(cls)) {
         /* Not a general sequence -- that opens up the road to
@@ -2717,8 +2718,9 @@ object_issubclass(PyThreadState *tstate, PyObject *derived, PyObject *cls)
         return recursive_issubclass(derived, cls);
     }
 
-    if (_PyUnion_Check(cls))
+    if (_PyUnion_Check(cls)) {
         cls = _Py_union_args(cls);
+    }
 
     if (PyTuple_Check(cls)) {