From 06df3a72dfe462c8fe4eac60dce0ef059b1738f8 Mon Sep 17 00:00:00 2001
From: Alexander Lakeev <alakeev@gmail.com>
Date: Sun, 13 Feb 2022 04:12:59 +0300
Subject: [PATCH 01/12] bpo-46730: Make @property AttributeError unique and
 sensible

The property decorator raises AttributeErrors with messages
that neither help to identify the problem nor lead to a possible solution.
This commit proposes changes in error messages to address the issue.
---
 Doc/howto/descriptor.rst  |  8 ++++----
 Lib/test/test_property.py |  6 +++---
 Objects/descrobject.c     | 12 ++++++------
 3 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/Doc/howto/descriptor.rst b/Doc/howto/descriptor.rst
index f8b1e00d96fadc..217810b9bb264f 100644
--- a/Doc/howto/descriptor.rst
+++ b/Doc/howto/descriptor.rst
@@ -991,17 +991,17 @@ here is a pure Python equivalent:
             if obj is None:
                 return self
             if self.fget is None:
-                raise AttributeError(f'unreadable attribute {self._name}')
+                raise AttributeError(f'unreadable property {self._name}')
             return self.fget(obj)
 
         def __set__(self, obj, value):
             if self.fset is None:
-                raise AttributeError(f"can't set attribute {self._name}")
+                raise AttributeError(f"no setter was defined for property {self._name}")
             self.fset(obj, value)
 
         def __delete__(self, obj):
             if self.fdel is None:
-                raise AttributeError(f"can't delete attribute {self._name}")
+                raise AttributeError(f"no deleter was defined for property {self._name}")
             self.fdel(obj)
 
         def getter(self, fget):
@@ -1456,7 +1456,7 @@ attributes stored in ``__slots__``:
     >>> mark.dept = 'Space Pirate'
     Traceback (most recent call last):
         ...
-    AttributeError: can't set attribute
+    AttributeError: no setter was defined for property
     >>> mark.location = 'Mars'
     Traceback (most recent call last):
         ...
diff --git a/Lib/test/test_property.py b/Lib/test/test_property.py
index 7f3813fc8cd15e..485e361c608a63 100644
--- a/Lib/test/test_property.py
+++ b/Lib/test/test_property.py
@@ -322,15 +322,15 @@ def setUpClass(cls):
         cls.obj = cls.cls()
 
     def test_get_property(self):
-        with self.assertRaisesRegex(AttributeError, self._format_exc_msg("unreadable attribute")):
+        with self.assertRaisesRegex(AttributeError, self._format_exc_msg("unreadable property")):
             self.obj.foo
 
     def test_set_property(self):
-        with self.assertRaisesRegex(AttributeError, self._format_exc_msg("can't set attribute")):
+        with self.assertRaisesRegex(AttributeError, self._format_exc_msg("no setter was defined for property")):
             self.obj.foo = None
 
     def test_del_property(self):
-        with self.assertRaisesRegex(AttributeError, self._format_exc_msg("can't delete attribute")):
+        with self.assertRaisesRegex(AttributeError, self._format_exc_msg("no deleter was defined for property")):
             del self.obj.foo
 
 
diff --git a/Objects/descrobject.c b/Objects/descrobject.c
index 95162683edd7d1..e074391e303c44 100644
--- a/Objects/descrobject.c
+++ b/Objects/descrobject.c
@@ -1586,9 +1586,9 @@ property_descr_get(PyObject *self, PyObject *obj, PyObject *type)
     propertyobject *gs = (propertyobject *)self;
     if (gs->prop_get == NULL) {
         if (gs->prop_name != NULL) {
-            PyErr_Format(PyExc_AttributeError, "unreadable attribute %R", gs->prop_name);
+            PyErr_Format(PyExc_AttributeError, "unreadable property %R", gs->prop_name);
         } else {
-            PyErr_SetString(PyExc_AttributeError, "unreadable attribute");
+            PyErr_SetString(PyExc_AttributeError, "unreadable property");
         }
 
         return NULL;
@@ -1614,15 +1614,15 @@ property_descr_set(PyObject *self, PyObject *obj, PyObject *value)
         if (gs->prop_name != NULL) {
             PyErr_Format(PyExc_AttributeError,
                         value == NULL ?
-                        "can't delete attribute %R" :
-                        "can't set attribute %R",
+                        "no deleter was defined for property %R" :
+                        "no setter was defined for property %R",
                         gs->prop_name);
         }
         else {
             PyErr_SetString(PyExc_AttributeError,
                             value == NULL ?
-                            "can't delete attribute" :
-                            "can't set attribute");
+                            "no deleter was defined for property" :
+                            "no setter was defined for property");
         }
         return -1;
     }

From 0b1ac6412b49295caeb6c3a1b6043799bdedf0fe Mon Sep 17 00:00:00 2001
From: Alexander Lakeev <alakeev@gmail.com>
Date: Sun, 13 Feb 2022 15:10:41 +0300
Subject: [PATCH 02/12] bpo-46730: Add more details on property origin to the
 AttributeError

This is an improvement to the initial patch for the bpo-46730.
It adds additional information on class that owns the property
that caused an AttributeError.
---
 Lib/test/test_property.py | 14 +++++++-------
 Lib/test/test_sys.py      |  2 +-
 Objects/descrobject.c     | 40 ++++++++++++++++++++++++++++++---------
 3 files changed, 39 insertions(+), 17 deletions(-)

diff --git a/Lib/test/test_property.py b/Lib/test/test_property.py
index 485e361c608a63..72562d8f46c553 100644
--- a/Lib/test/test_property.py
+++ b/Lib/test/test_property.py
@@ -314,35 +314,35 @@ class _PropertyUnreachableAttribute:
     obj = None
     cls = None
 
-    def _format_exc_msg(self, msg):
-        return self.msg_format.format(msg)
+    def _format_exc_msg(self, *msg):
+        return self.msg_format.format(*msg)
 
     @classmethod
     def setUpClass(cls):
         cls.obj = cls.cls()
 
     def test_get_property(self):
-        with self.assertRaisesRegex(AttributeError, self._format_exc_msg("unreadable property")):
+        with self.assertRaisesRegex(AttributeError, self._format_exc_msg("has no getter")):
             self.obj.foo
 
     def test_set_property(self):
-        with self.assertRaisesRegex(AttributeError, self._format_exc_msg("no setter was defined for property")):
+        with self.assertRaisesRegex(AttributeError, self._format_exc_msg("has no setter")):
             self.obj.foo = None
 
     def test_del_property(self):
-        with self.assertRaisesRegex(AttributeError, self._format_exc_msg("no deleter was defined for property")):
+        with self.assertRaisesRegex(AttributeError, self._format_exc_msg("has no deleter")):
             del self.obj.foo
 
 
 class PropertyUnreachableAttributeWithName(_PropertyUnreachableAttribute, unittest.TestCase):
-    msg_format = "^{} 'foo'$"
+    msg_format = "^property 'foo' originating from 'cls' {}$"
 
     class cls:
         foo = property()
 
 
 class PropertyUnreachableAttributeNoName(_PropertyUnreachableAttribute, unittest.TestCase):
-    msg_format = "^{}$"
+    msg_format = "^property {}$"
 
     class cls:
         pass
diff --git a/Lib/test/test_sys.py b/Lib/test/test_sys.py
index 21d7ccbf709666..2b4511c980f92e 100644
--- a/Lib/test/test_sys.py
+++ b/Lib/test/test_sys.py
@@ -1450,7 +1450,7 @@ def getx(self): return self.__x
             def setx(self, value): self.__x = value
             def delx(self): del self.__x
             x = property(getx, setx, delx, "")
-            check(x, size('5Pi'))
+            check(x, size('6Pi'))
         # PyCapsule
         # XXX
         # rangeiterator
diff --git a/Objects/descrobject.c b/Objects/descrobject.c
index e074391e303c44..dc28131302661f 100644
--- a/Objects/descrobject.c
+++ b/Objects/descrobject.c
@@ -1485,6 +1485,7 @@ typedef struct {
     PyObject *prop_del;
     PyObject *prop_doc;
     PyObject *prop_name;
+    PyObject *owner_name;
     int getter_doc;
 } propertyobject;
 
@@ -1544,11 +1545,15 @@ property_set_name(PyObject *self, PyObject *args) {
     }
 
     propertyobject *prop = (propertyobject *)self;
+    PyObject *owner_name = PyObject_GetAttrString(PyTuple_GET_ITEM(args, 0), "__name__");
     PyObject *name = PyTuple_GET_ITEM(args, 1);
 
     Py_XINCREF(name);
     Py_XSETREF(prop->prop_name, name);
 
+    Py_XINCREF(owner_name);
+    Py_XSETREF(prop->owner_name, owner_name);
+
     Py_RETURN_NONE;
 }
 
@@ -1572,6 +1577,7 @@ property_dealloc(PyObject *self)
     Py_XDECREF(gs->prop_del);
     Py_XDECREF(gs->prop_doc);
     Py_XDECREF(gs->prop_name);
+    Py_XDECREF(gs->owner_name);
     Py_TYPE(self)->tp_free(self);
 }
 
@@ -1585,10 +1591,15 @@ property_descr_get(PyObject *self, PyObject *obj, PyObject *type)
 
     propertyobject *gs = (propertyobject *)self;
     if (gs->prop_get == NULL) {
-        if (gs->prop_name != NULL) {
-            PyErr_Format(PyExc_AttributeError, "unreadable property %R", gs->prop_name);
+        if (gs->prop_name != NULL && gs->owner_name != NULL) {
+            PyErr_Format(PyExc_AttributeError,
+                         "property %R originating from %R has no getter",
+                         gs->prop_name,
+                         gs->owner_name);
+        } else if (gs->prop_name != NULL) {
+            PyErr_Format(PyExc_AttributeError, "property %R has no getter", gs->prop_name);
         } else {
-            PyErr_SetString(PyExc_AttributeError, "unreadable property");
+            PyErr_SetString(PyExc_AttributeError, "property has no getter");
         }
 
         return NULL;
@@ -1611,18 +1622,26 @@ property_descr_set(PyObject *self, PyObject *obj, PyObject *value)
     }
 
     if (func == NULL) {
-        if (gs->prop_name != NULL) {
+        if (gs->prop_name != NULL && gs->owner_name != NULL) {
             PyErr_Format(PyExc_AttributeError,
                         value == NULL ?
-                        "no deleter was defined for property %R" :
-                        "no setter was defined for property %R",
-                        gs->prop_name);
+                        "property %R originating from %R has no deleter" :
+                        "property %R originating from %R has no setter",
+                        gs->prop_name,
+                        gs->owner_name);
+        }
+        else if (gs->prop_name != NULL) {
+            PyErr_Format(PyExc_AttributeError,
+                         value == NULL ?
+                         "property %R has no deleter" :
+                         "property %R has no setter",
+                         gs->prop_name);
         }
         else {
             PyErr_SetString(PyExc_AttributeError,
                             value == NULL ?
-                            "no deleter was defined for property" :
-                            "no setter was defined for property");
+                            "property has no deleter" :
+                            "property has no setter");
         }
         return -1;
     }
@@ -1680,6 +1699,9 @@ property_copy(PyObject *old, PyObject *get, PyObject *set, PyObject *del)
 
     Py_XINCREF(pold->prop_name);
     Py_XSETREF(((propertyobject *) new)->prop_name, pold->prop_name);
+
+    Py_XINCREF(pold->owner_name);
+    Py_XSETREF(((propertyobject *) new)->owner_name, pold->owner_name);
     return new;
 }
 

From e86f544de62e18e95d18fb95f146131ecbee95c0 Mon Sep 17 00:00:00 2001
From: Alexander Lakeev <alakeev@gmail.com>
Date: Mon, 14 Feb 2022 14:19:54 +0300
Subject: [PATCH 03/12] bpo-46730: Make AttributeError show self.__qualname__
 instead of owner type

---
 Lib/test/test_property.py |  4 ++--
 Lib/test/test_sys.py      |  2 +-
 Objects/descrobject.c     | 49 +++++++++++++++------------------------
 3 files changed, 22 insertions(+), 33 deletions(-)

diff --git a/Lib/test/test_property.py b/Lib/test/test_property.py
index 72562d8f46c553..8d44e56c739c57 100644
--- a/Lib/test/test_property.py
+++ b/Lib/test/test_property.py
@@ -335,14 +335,14 @@ def test_del_property(self):
 
 
 class PropertyUnreachableAttributeWithName(_PropertyUnreachableAttribute, unittest.TestCase):
-    msg_format = "^property 'foo' originating from 'cls' {}$"
+    msg_format = "^property 'foo' in object of type 'PropertyUnreachableAttributeWithName.cls' {}$"
 
     class cls:
         foo = property()
 
 
 class PropertyUnreachableAttributeNoName(_PropertyUnreachableAttribute, unittest.TestCase):
-    msg_format = "^property {}$"
+    msg_format = "^property in object of type 'PropertyUnreachableAttributeNoName.cls' {}$"
 
     class cls:
         pass
diff --git a/Lib/test/test_sys.py b/Lib/test/test_sys.py
index 2b4511c980f92e..21d7ccbf709666 100644
--- a/Lib/test/test_sys.py
+++ b/Lib/test/test_sys.py
@@ -1450,7 +1450,7 @@ def getx(self): return self.__x
             def setx(self, value): self.__x = value
             def delx(self): del self.__x
             x = property(getx, setx, delx, "")
-            check(x, size('6Pi'))
+            check(x, size('5Pi'))
         # PyCapsule
         # XXX
         # rangeiterator
diff --git a/Objects/descrobject.c b/Objects/descrobject.c
index dc28131302661f..3272e59ed2c989 100644
--- a/Objects/descrobject.c
+++ b/Objects/descrobject.c
@@ -1485,7 +1485,6 @@ typedef struct {
     PyObject *prop_del;
     PyObject *prop_doc;
     PyObject *prop_name;
-    PyObject *owner_name;
     int getter_doc;
 } propertyobject;
 
@@ -1545,15 +1544,11 @@ property_set_name(PyObject *self, PyObject *args) {
     }
 
     propertyobject *prop = (propertyobject *)self;
-    PyObject *owner_name = PyObject_GetAttrString(PyTuple_GET_ITEM(args, 0), "__name__");
     PyObject *name = PyTuple_GET_ITEM(args, 1);
 
     Py_XINCREF(name);
     Py_XSETREF(prop->prop_name, name);
 
-    Py_XINCREF(owner_name);
-    Py_XSETREF(prop->owner_name, owner_name);
-
     Py_RETURN_NONE;
 }
 
@@ -1577,7 +1572,6 @@ property_dealloc(PyObject *self)
     Py_XDECREF(gs->prop_del);
     Py_XDECREF(gs->prop_doc);
     Py_XDECREF(gs->prop_name);
-    Py_XDECREF(gs->owner_name);
     Py_TYPE(self)->tp_free(self);
 }
 
@@ -1591,15 +1585,15 @@ property_descr_get(PyObject *self, PyObject *obj, PyObject *type)
 
     propertyobject *gs = (propertyobject *)self;
     if (gs->prop_get == NULL) {
-        if (gs->prop_name != NULL && gs->owner_name != NULL) {
+        if (gs->prop_name != NULL) {
             PyErr_Format(PyExc_AttributeError,
-                         "property %R originating from %R has no getter",
+                         "property %R in object of type %R has no getter",
                          gs->prop_name,
-                         gs->owner_name);
-        } else if (gs->prop_name != NULL) {
-            PyErr_Format(PyExc_AttributeError, "property %R has no getter", gs->prop_name);
+                         PyType_GetQualName(Py_TYPE(obj)));
         } else {
-            PyErr_SetString(PyExc_AttributeError, "property has no getter");
+            PyErr_Format(PyExc_AttributeError,
+                         "property in object of type %R has no getter",
+                         PyType_GetQualName(Py_TYPE(obj)));
         }
 
         return NULL;
@@ -1622,26 +1616,24 @@ property_descr_set(PyObject *self, PyObject *obj, PyObject *value)
     }
 
     if (func == NULL) {
-        if (gs->prop_name != NULL && gs->owner_name != NULL) {
+        if (gs->prop_name != NULL && obj != NULL) {
             PyErr_Format(PyExc_AttributeError,
                         value == NULL ?
-                        "property %R originating from %R has no deleter" :
-                        "property %R originating from %R has no setter",
+                        "property %R in object of type %R has no deleter" :
+                        "property %R in object of type %R has no setter",
                         gs->prop_name,
-                        gs->owner_name);
-        }
-        else if (gs->prop_name != NULL) {
+                        PyType_GetQualName(Py_TYPE(obj)));
+        } else if (obj != NULL) {
             PyErr_Format(PyExc_AttributeError,
-                         value == NULL ?
-                         "property %R has no deleter" :
-                         "property %R has no setter",
-                         gs->prop_name);
-        }
-        else {
-            PyErr_SetString(PyExc_AttributeError,
                             value == NULL ?
-                            "property has no deleter" :
-                            "property has no setter");
+                            "property in object of type %R has no deleter" :
+                            "property in object of type %R has no setter",
+                            PyType_GetQualName(Py_TYPE(obj)));
+        } else {
+            PyErr_SetString(PyExc_AttributeError,
+                         value == NULL ?
+                         "property has no deleter" :
+                         "property has no setter");
         }
         return -1;
     }
@@ -1699,9 +1691,6 @@ property_copy(PyObject *old, PyObject *get, PyObject *set, PyObject *del)
 
     Py_XINCREF(pold->prop_name);
     Py_XSETREF(((propertyobject *) new)->prop_name, pold->prop_name);
-
-    Py_XINCREF(pold->owner_name);
-    Py_XSETREF(((propertyobject *) new)->owner_name, pold->owner_name);
     return new;
 }
 

From 921d3e50149024dfa0db9d3b1cc8f9099da8a1ab Mon Sep 17 00:00:00 2001
From: Alexander Lakeev <alakeev@gmail.com>
Date: Mon, 14 Feb 2022 15:32:01 +0300
Subject: [PATCH 04/12] bpo-46730: Adjusted documentation according to the
 latest changes

---
 Doc/howto/descriptor.rst | 6 +++---
 Objects/descrobject.c    | 6 +++---
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/Doc/howto/descriptor.rst b/Doc/howto/descriptor.rst
index 217810b9bb264f..5b14f477cbafa9 100644
--- a/Doc/howto/descriptor.rst
+++ b/Doc/howto/descriptor.rst
@@ -991,17 +991,17 @@ here is a pure Python equivalent:
             if obj is None:
                 return self
             if self.fget is None:
-                raise AttributeError(f'unreadable property {self._name}')
+                raise AttributeError(f"property '{self._name}' has no getter")
             return self.fget(obj)
 
         def __set__(self, obj, value):
             if self.fset is None:
-                raise AttributeError(f"no setter was defined for property {self._name}")
+                raise AttributeError(f"property '{self._name}' has no setter")
             self.fset(obj, value)
 
         def __delete__(self, obj):
             if self.fdel is None:
-                raise AttributeError(f"no deleter was defined for property {self._name}")
+                raise AttributeError(f"property '{self._name}' has no deleter")
             self.fdel(obj)
 
         def getter(self, fget):
diff --git a/Objects/descrobject.c b/Objects/descrobject.c
index 3272e59ed2c989..3d044e22b127e6 100644
--- a/Objects/descrobject.c
+++ b/Objects/descrobject.c
@@ -1463,17 +1463,17 @@ class property(object):
         if inst is None:
             return self
         if self.__get is None:
-            raise AttributeError, "unreadable attribute"
+            raise AttributeError, "property has no getter"
         return self.__get(inst)
 
     def __set__(self, inst, value):
         if self.__set is None:
-            raise AttributeError, "can't set attribute"
+            raise AttributeError, "property has no setter"
         return self.__set(inst, value)
 
     def __delete__(self, inst):
         if self.__del is None:
-            raise AttributeError, "can't delete attribute"
+            raise AttributeError, "property has no deleter"
         return self.__del(inst)
 
 */

From f1cae0c1aca92ffaa13491d9fba3a48dd02386e2 Mon Sep 17 00:00:00 2001
From: Alexander Lakeev <alakeev@gmail.com>
Date: Mon, 14 Feb 2022 23:15:27 +0300
Subject: [PATCH 05/12] bpo-46730: Fix regex dot in tests

Properly escape dot character and return `_format_exc_msg` function to its initial state.
---
 Lib/test/test_property.py | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/Lib/test/test_property.py b/Lib/test/test_property.py
index 8d44e56c739c57..c011fb77aa4b15 100644
--- a/Lib/test/test_property.py
+++ b/Lib/test/test_property.py
@@ -314,8 +314,8 @@ class _PropertyUnreachableAttribute:
     obj = None
     cls = None
 
-    def _format_exc_msg(self, *msg):
-        return self.msg_format.format(*msg)
+    def _format_exc_msg(self, msg):
+        return self.msg_format.format(msg)
 
     @classmethod
     def setUpClass(cls):
@@ -335,14 +335,14 @@ def test_del_property(self):
 
 
 class PropertyUnreachableAttributeWithName(_PropertyUnreachableAttribute, unittest.TestCase):
-    msg_format = "^property 'foo' in object of type 'PropertyUnreachableAttributeWithName.cls' {}$"
+    msg_format = r"^property 'foo' in object of type 'PropertyUnreachableAttributeWithName\.cls' {}$"
 
     class cls:
         foo = property()
 
 
 class PropertyUnreachableAttributeNoName(_PropertyUnreachableAttribute, unittest.TestCase):
-    msg_format = "^property in object of type 'PropertyUnreachableAttributeNoName.cls' {}$"
+    msg_format = "^property in object of type 'PropertyUnreachableAttributeNoName\.cls' {}$"
 
     class cls:
         pass

From 83cae8812838450621a8ecb0717b34d490c1fcda Mon Sep 17 00:00:00 2001
From: Alexander Lakeev <alakeev@gmail.com>
Date: Mon, 14 Feb 2022 23:26:38 +0300
Subject: [PATCH 06/12] bpo-46730: Make changes comply with PEP 7

---
 Objects/descrobject.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/Objects/descrobject.c b/Objects/descrobject.c
index 3d044e22b127e6..0697371c4e8519 100644
--- a/Objects/descrobject.c
+++ b/Objects/descrobject.c
@@ -1590,7 +1590,8 @@ property_descr_get(PyObject *self, PyObject *obj, PyObject *type)
                          "property %R in object of type %R has no getter",
                          gs->prop_name,
                          PyType_GetQualName(Py_TYPE(obj)));
-        } else {
+        }
+        else {
             PyErr_Format(PyExc_AttributeError,
                          "property in object of type %R has no getter",
                          PyType_GetQualName(Py_TYPE(obj)));
@@ -1623,13 +1624,15 @@ property_descr_set(PyObject *self, PyObject *obj, PyObject *value)
                         "property %R in object of type %R has no setter",
                         gs->prop_name,
                         PyType_GetQualName(Py_TYPE(obj)));
-        } else if (obj != NULL) {
+        }
+        else if (obj != NULL) {
             PyErr_Format(PyExc_AttributeError,
                             value == NULL ?
                             "property in object of type %R has no deleter" :
                             "property in object of type %R has no setter",
                             PyType_GetQualName(Py_TYPE(obj)));
-        } else {
+        }
+        else {
             PyErr_SetString(PyExc_AttributeError,
                          value == NULL ?
                          "property has no deleter" :

From 759427709ae8db023400aa9baafa6ec9c784ede3 Mon Sep 17 00:00:00 2001
From: Alexander Lakeev <alakeev@gmail.com>
Date: Mon, 14 Feb 2022 23:45:16 +0300
Subject: [PATCH 07/12] bpo-46730: Change preposition from "in" to "of" in
 error

---
 Lib/test/test_property.py |  4 ++--
 Objects/descrobject.c     | 12 ++++++------
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/Lib/test/test_property.py b/Lib/test/test_property.py
index c011fb77aa4b15..6ec6688b57aed3 100644
--- a/Lib/test/test_property.py
+++ b/Lib/test/test_property.py
@@ -335,14 +335,14 @@ def test_del_property(self):
 
 
 class PropertyUnreachableAttributeWithName(_PropertyUnreachableAttribute, unittest.TestCase):
-    msg_format = r"^property 'foo' in object of type 'PropertyUnreachableAttributeWithName\.cls' {}$"
+    msg_format = r"^property 'foo' of object of type 'PropertyUnreachableAttributeWithName\.cls' {}$"
 
     class cls:
         foo = property()
 
 
 class PropertyUnreachableAttributeNoName(_PropertyUnreachableAttribute, unittest.TestCase):
-    msg_format = "^property in object of type 'PropertyUnreachableAttributeNoName\.cls' {}$"
+    msg_format = "^property of object of type 'PropertyUnreachableAttributeNoName\.cls' {}$"
 
     class cls:
         pass
diff --git a/Objects/descrobject.c b/Objects/descrobject.c
index 0697371c4e8519..236a923b5bc6a2 100644
--- a/Objects/descrobject.c
+++ b/Objects/descrobject.c
@@ -1587,13 +1587,13 @@ property_descr_get(PyObject *self, PyObject *obj, PyObject *type)
     if (gs->prop_get == NULL) {
         if (gs->prop_name != NULL) {
             PyErr_Format(PyExc_AttributeError,
-                         "property %R in object of type %R has no getter",
+                         "property %R of object of type %R has no getter",
                          gs->prop_name,
                          PyType_GetQualName(Py_TYPE(obj)));
         }
         else {
             PyErr_Format(PyExc_AttributeError,
-                         "property in object of type %R has no getter",
+                         "property of object of type %R has no getter",
                          PyType_GetQualName(Py_TYPE(obj)));
         }
 
@@ -1620,16 +1620,16 @@ property_descr_set(PyObject *self, PyObject *obj, PyObject *value)
         if (gs->prop_name != NULL && obj != NULL) {
             PyErr_Format(PyExc_AttributeError,
                         value == NULL ?
-                        "property %R in object of type %R has no deleter" :
-                        "property %R in object of type %R has no setter",
+                        "property %R of object of type %R has no deleter" :
+                        "property %R of object of type %R has no setter",
                         gs->prop_name,
                         PyType_GetQualName(Py_TYPE(obj)));
         }
         else if (obj != NULL) {
             PyErr_Format(PyExc_AttributeError,
                             value == NULL ?
-                            "property in object of type %R has no deleter" :
-                            "property in object of type %R has no setter",
+                            "property of object of type %R has no deleter" :
+                            "property of object of type %R has no setter",
                             PyType_GetQualName(Py_TYPE(obj)));
         }
         else {

From 7399805b578e49e533eae1bf63e54798a891344f Mon Sep 17 00:00:00 2001
From: "blurb-it[bot]" <43283697+blurb-it[bot]@users.noreply.github.com>
Date: Mon, 14 Feb 2022 21:04:44 +0000
Subject: [PATCH 08/12] =?UTF-8?q?=F0=9F=93=9C=F0=9F=A4=96=20Added=20by=20b?=
 =?UTF-8?q?lurb=5Fit.?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../Core and Builtins/2022-02-14-21-04-43.bpo-46730.rYJ1w5.rst | 3 +++
 1 file changed, 3 insertions(+)
 create mode 100644 Misc/NEWS.d/next/Core and Builtins/2022-02-14-21-04-43.bpo-46730.rYJ1w5.rst

diff --git a/Misc/NEWS.d/next/Core and Builtins/2022-02-14-21-04-43.bpo-46730.rYJ1w5.rst b/Misc/NEWS.d/next/Core and Builtins/2022-02-14-21-04-43.bpo-46730.rYJ1w5.rst
new file mode 100644
index 00000000000000..473b595545370b
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2022-02-14-21-04-43.bpo-46730.rYJ1w5.rst	
@@ -0,0 +1,3 @@
+Message of AttributeError caused by getting, setting or deleting a property
+without the corresponding function now mentions that the attribute is in fact
+a property and also specifies type of the class that it belongs to.

From 236e579a6c84fae92d3c53312a41111c0d990b82 Mon Sep 17 00:00:00 2001
From: Alexander Lakeev <alakeev@gmail.com>
Date: Tue, 15 Feb 2022 00:29:00 +0300
Subject: [PATCH 09/12] Update ACKS

---
 Misc/ACKS | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Misc/ACKS b/Misc/ACKS
index 6df339c3e145bf..64bd91d7d69053 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -985,6 +985,7 @@ Erno Kuusela
 Ross Lagerwall
 Cameron Laird
 Loïc Lajeanne
+Alexander Lakeev
 David Lam
 Thomas Lamb
 Valerie Lambert

From 1de53bba3c4066b9d44f7edfe7c0796fc4688336 Mon Sep 17 00:00:00 2001
From: Alexander Lakeev <alakeev@gmail.com>
Date: Tue, 15 Feb 2022 21:51:41 +0300
Subject: [PATCH 10/12] bpo-46730: Remove "of type of" from the message

---
 Lib/test/test_property.py |  4 ++--
 Objects/descrobject.c     | 12 ++++++------
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/Lib/test/test_property.py b/Lib/test/test_property.py
index 6ec6688b57aed3..e7b7effb920585 100644
--- a/Lib/test/test_property.py
+++ b/Lib/test/test_property.py
@@ -335,14 +335,14 @@ def test_del_property(self):
 
 
 class PropertyUnreachableAttributeWithName(_PropertyUnreachableAttribute, unittest.TestCase):
-    msg_format = r"^property 'foo' of object of type 'PropertyUnreachableAttributeWithName\.cls' {}$"
+    msg_format = r"^property 'foo' of object 'PropertyUnreachableAttributeWithName\.cls' {}$"
 
     class cls:
         foo = property()
 
 
 class PropertyUnreachableAttributeNoName(_PropertyUnreachableAttribute, unittest.TestCase):
-    msg_format = "^property of object of type 'PropertyUnreachableAttributeNoName\.cls' {}$"
+    msg_format = "^property of object 'PropertyUnreachableAttributeNoName\.cls' {}$"
 
     class cls:
         pass
diff --git a/Objects/descrobject.c b/Objects/descrobject.c
index 236a923b5bc6a2..9000b026086979 100644
--- a/Objects/descrobject.c
+++ b/Objects/descrobject.c
@@ -1587,13 +1587,13 @@ property_descr_get(PyObject *self, PyObject *obj, PyObject *type)
     if (gs->prop_get == NULL) {
         if (gs->prop_name != NULL) {
             PyErr_Format(PyExc_AttributeError,
-                         "property %R of object of type %R has no getter",
+                         "property %R of object %R has no getter",
                          gs->prop_name,
                          PyType_GetQualName(Py_TYPE(obj)));
         }
         else {
             PyErr_Format(PyExc_AttributeError,
-                         "property of object of type %R has no getter",
+                         "property of object %R has no getter",
                          PyType_GetQualName(Py_TYPE(obj)));
         }
 
@@ -1620,16 +1620,16 @@ property_descr_set(PyObject *self, PyObject *obj, PyObject *value)
         if (gs->prop_name != NULL && obj != NULL) {
             PyErr_Format(PyExc_AttributeError,
                         value == NULL ?
-                        "property %R of object of type %R has no deleter" :
-                        "property %R of object of type %R has no setter",
+                        "property %R of object %R has no deleter" :
+                        "property %R of object %R has no setter",
                         gs->prop_name,
                         PyType_GetQualName(Py_TYPE(obj)));
         }
         else if (obj != NULL) {
             PyErr_Format(PyExc_AttributeError,
                             value == NULL ?
-                            "property of object of type %R has no deleter" :
-                            "property of object of type %R has no setter",
+                            "property of object %R has no deleter" :
+                            "property of object %R has no setter",
                             PyType_GetQualName(Py_TYPE(obj)));
         }
         else {

From 3d931a171136189f8f9d28898eecc669d2a6720e Mon Sep 17 00:00:00 2001
From: Alexander Lakeev <alakeev@gmail.com>
Date: Tue, 15 Feb 2022 22:13:38 +0300
Subject: [PATCH 11/12] bpo-46730: Change the order of words

---
 Lib/test/test_property.py |  4 ++--
 Objects/descrobject.c     | 12 ++++++------
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/Lib/test/test_property.py b/Lib/test/test_property.py
index e7b7effb920585..7d1c4a1e128805 100644
--- a/Lib/test/test_property.py
+++ b/Lib/test/test_property.py
@@ -335,14 +335,14 @@ def test_del_property(self):
 
 
 class PropertyUnreachableAttributeWithName(_PropertyUnreachableAttribute, unittest.TestCase):
-    msg_format = r"^property 'foo' of object 'PropertyUnreachableAttributeWithName\.cls' {}$"
+    msg_format = r"^property 'foo' of 'PropertyUnreachableAttributeWithName\.cls' object {}$"
 
     class cls:
         foo = property()
 
 
 class PropertyUnreachableAttributeNoName(_PropertyUnreachableAttribute, unittest.TestCase):
-    msg_format = "^property of object 'PropertyUnreachableAttributeNoName\.cls' {}$"
+    msg_format = "^property of 'PropertyUnreachableAttributeNoName\.cls' object {}$"
 
     class cls:
         pass
diff --git a/Objects/descrobject.c b/Objects/descrobject.c
index 9000b026086979..9379ad65de43ef 100644
--- a/Objects/descrobject.c
+++ b/Objects/descrobject.c
@@ -1587,13 +1587,13 @@ property_descr_get(PyObject *self, PyObject *obj, PyObject *type)
     if (gs->prop_get == NULL) {
         if (gs->prop_name != NULL) {
             PyErr_Format(PyExc_AttributeError,
-                         "property %R of object %R has no getter",
+                         "property %R of %R object has no getter",
                          gs->prop_name,
                          PyType_GetQualName(Py_TYPE(obj)));
         }
         else {
             PyErr_Format(PyExc_AttributeError,
-                         "property of object %R has no getter",
+                         "property of %R object has no getter",
                          PyType_GetQualName(Py_TYPE(obj)));
         }
 
@@ -1620,16 +1620,16 @@ property_descr_set(PyObject *self, PyObject *obj, PyObject *value)
         if (gs->prop_name != NULL && obj != NULL) {
             PyErr_Format(PyExc_AttributeError,
                         value == NULL ?
-                        "property %R of object %R has no deleter" :
-                        "property %R of object %R has no setter",
+                        "property %R of %R object has no deleter" :
+                        "property %R of %R object has no setter",
                         gs->prop_name,
                         PyType_GetQualName(Py_TYPE(obj)));
         }
         else if (obj != NULL) {
             PyErr_Format(PyExc_AttributeError,
                             value == NULL ?
-                            "property of object %R has no deleter" :
-                            "property of object %R has no setter",
+                            "property of %R object has no deleter" :
+                            "property of %R object has no setter",
                             PyType_GetQualName(Py_TYPE(obj)));
         }
         else {

From bc901754a3362af749d611fdb97d27e8cd7c9c30 Mon Sep 17 00:00:00 2001
From: Alexander Lakeev <alakeev@gmail.com>
Date: Wed, 16 Feb 2022 03:28:45 +0300
Subject: [PATCH 12/12] bpo-46730: Fix doctest for property

---
 Doc/howto/descriptor.rst | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Doc/howto/descriptor.rst b/Doc/howto/descriptor.rst
index 5b14f477cbafa9..4f6389e3b2d487 100644
--- a/Doc/howto/descriptor.rst
+++ b/Doc/howto/descriptor.rst
@@ -1456,7 +1456,7 @@ attributes stored in ``__slots__``:
     >>> mark.dept = 'Space Pirate'
     Traceback (most recent call last):
         ...
-    AttributeError: no setter was defined for property
+    AttributeError: property 'dept' of 'Immutable' object has no setter
     >>> mark.location = 'Mars'
     Traceback (most recent call last):
         ...