From abc121c0268e350cc7482e32d0523e70dd211efc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?B=C3=A9n=C3=A9dikt=20Tran?=
 <10796600+picnixz@users.noreply.github.com>
Date: Sun, 27 Oct 2024 14:43:14 +0100
Subject: [PATCH 1/5] Add versioning to XML elements.

---
 Modules/_elementtree.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/Modules/_elementtree.c b/Modules/_elementtree.c
index e134e096e044b7..cbad0a063bb981 100644
--- a/Modules/_elementtree.c
+++ b/Modules/_elementtree.c
@@ -230,6 +230,10 @@ typedef struct {
 
     PyObject* _children[STATIC_CHILDREN];
 
+    /* incremented whenever 'attrib' is externally mutated */
+    uint64_t attrib_version;
+    /* incremented whenever children are externally mutated */
+    uint64_t version;
 } ElementObjectExtra;
 
 typedef struct {
@@ -279,6 +283,9 @@ create_extra(ElementObject* self, PyObject* attrib)
     self->extra->allocated = STATIC_CHILDREN;
     self->extra->children = self->extra->_children;
 
+    self->extra->attrib_version = 0;
+    self->extra->version = 0;
+
     return 0;
 }
 
@@ -506,6 +513,7 @@ element_resize(ElementObject* self, Py_ssize_t extra)
         }
         self->extra->children = children;
         self->extra->allocated = size;
+        self->extra->version++;
     }
 
     return 0;
@@ -539,6 +547,7 @@ element_add_subelement(elementtreestate *st, ElementObject *self,
     self->extra->children[self->extra->length] = Py_NewRef(element);
 
     self->extra->length++;
+    self->extra->version++;
 
     return 0;
 }
@@ -780,6 +789,7 @@ _elementtree_Element___copy___impl(ElementObject *self, PyTypeObject *cls)
 
         assert(!element->extra->length);
         element->extra->length = self->extra->length;
+        element->extra->version = self->extra->version;
     }
 
     return (PyObject*) element;
@@ -847,6 +857,7 @@ _elementtree_Element___deepcopy___impl(ElementObject *self, PyObject *memo)
         if (element_resize(element, self->extra->length) < 0)
             goto error;
 
+        // TODO(picnixz): check for an evil child's __deepcopy__ on 'self'
         for (i = 0; i < self->extra->length; i++) {
             PyObject* child = deepcopy(st, self->extra->children[i], memo);
             if (!child || !Element_Check(st, child)) {
@@ -862,6 +873,7 @@ _elementtree_Element___deepcopy___impl(ElementObject *self, PyObject *memo)
 
         assert(!element->extra->length);
         element->extra->length = self->extra->length;
+        element->extra->version = 0;
     }
 
     /* add object to memo dictionary (so deepcopy won't visit it again) */
@@ -1017,10 +1029,12 @@ element_setstate_from_attributes(elementtreestate *st,
 
     Py_XSETREF(self->tag, Py_NewRef(tag));
 
+    // TODO(picnix): determine how versioning would work with an evil text
     text = text ? JOIN_SET(text, PyList_CheckExact(text)) : Py_None;
     Py_INCREF(JOIN_OBJ(text));
     _set_joined_ptr(&self->text, text);
 
+    // TODO(picnix): determine how versioning would work with an evil tail
     tail = tail ? JOIN_SET(tail, PyList_CheckExact(tail)) : Py_None;
     Py_INCREF(JOIN_OBJ(tail));
     _set_joined_ptr(&self->tail, tail);
@@ -1071,6 +1085,7 @@ element_setstate_from_attributes(elementtreestate *st,
 
         assert(!self->extra->length);
         self->extra->length = nchildren;
+        self->extra->version++;
     }
     else {
         if (element_resize(self, 0)) {
@@ -1080,6 +1095,7 @@ element_setstate_from_attributes(elementtreestate *st,
 
     /* Stash attrib. */
     Py_XSETREF(self->extra->attrib, Py_XNewRef(attrib));
+    self->extra->attrib_version++;
     dealloc_extra(oldextra);
 
     Py_RETURN_NONE;
@@ -1548,6 +1564,7 @@ _elementtree_Element_insert_impl(ElementObject *self, Py_ssize_t index,
     self->extra->children[index] = Py_NewRef(subelement);
 
     self->extra->length++;
+    self->extra->version++;
 
     Py_RETURN_NONE;
 }
@@ -1645,6 +1662,7 @@ _elementtree_Element_remove_impl(ElementObject *self, PyObject *subelement)
         return NULL;
     }
 
+    // TODO(picnixz): check against evil __eq__
     for (i = 0; i < self->extra->length; i++) {
         if (self->extra->children[i] == subelement)
             break;
@@ -1669,6 +1687,7 @@ _elementtree_Element_remove_impl(ElementObject *self, PyObject *subelement)
     self->extra->length--;
     for (; i < self->extra->length; i++)
         self->extra->children[i] = self->extra->children[i+1];
+    self->extra->version++;
 
     Py_DECREF(found);
     Py_RETURN_NONE;
@@ -1724,6 +1743,7 @@ _elementtree_Element_set_impl(ElementObject *self, PyObject *key,
     if (PyDict_SetItem(attrib, key, value) < 0)
         return NULL;
 
+    self->extra->attrib_version++;
     Py_RETURN_NONE;
 }
 
@@ -1757,6 +1777,7 @@ element_setitem(PyObject* self_, Py_ssize_t index, PyObject* item)
             self->extra->children[i] = self->extra->children[i+1];
     }
 
+    self->extra->version++;
     Py_DECREF(old);
 
     return 0;
@@ -1907,6 +1928,7 @@ element_ass_subscr(PyObject* self_, PyObject* item, PyObject* value)
             }
 
             self->extra->length -= slicelen;
+            self->extra->version++;
 
             /* Discard the recycle list with all the deleted sub-elements */
             Py_DECREF(recycle);
@@ -1982,6 +2004,7 @@ element_ass_subscr(PyObject* self_, PyObject* item, PyObject* value)
         }
 
         self->extra->length += newlen - slicelen;
+        self->extra->version++;
 
         Py_DECREF(seq);
 
@@ -2078,6 +2101,7 @@ element_attrib_setter(ElementObject *self, PyObject *value, void *closure)
             return -1;
     }
     Py_XSETREF(self->extra->attrib, Py_NewRef(value));
+    self->extra->attrib_version++;
     return 0;
 }
 

From 4efa51739e6f5ff42b97314ad9bf660983bc3cdd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?B=C3=A9n=C3=A9dikt=20Tran?=
 <10796600+picnixz@users.noreply.github.com>
Date: Sun, 27 Oct 2024 15:44:55 +0100
Subject: [PATCH 2/5] fix tests

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

diff --git a/Lib/test/test_xml_etree_c.py b/Lib/test/test_xml_etree_c.py
index 3a0fc572f457ff..8f371951f1c08d 100644
--- a/Lib/test/test_xml_etree_c.py
+++ b/Lib/test/test_xml_etree_c.py
@@ -234,7 +234,7 @@ class SizeofTest(unittest.TestCase):
     def setUp(self):
         self.elementsize = support.calcobjsize('5P')
         # extra
-        self.extra = struct.calcsize('PnnP4P')
+        self.extra = struct.calcsize('PnnP4Pnn')
 
     check_sizeof = support.check_sizeof
 

From 4ca3cf04a5c56599c39f7b8caabdc3188d914fe4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?B=C3=A9n=C3=A9dikt=20Tran?=
 <10796600+picnixz@users.noreply.github.com>
Date: Sun, 27 Oct 2024 16:24:26 +0100
Subject: [PATCH 3/5] fix portability issues

---
 Lib/test/test_xml_etree_c.py | 2 +-
 Modules/_elementtree.c       | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/Lib/test/test_xml_etree_c.py b/Lib/test/test_xml_etree_c.py
index 8f371951f1c08d..aa95753fed2a49 100644
--- a/Lib/test/test_xml_etree_c.py
+++ b/Lib/test/test_xml_etree_c.py
@@ -234,7 +234,7 @@ class SizeofTest(unittest.TestCase):
     def setUp(self):
         self.elementsize = support.calcobjsize('5P')
         # extra
-        self.extra = struct.calcsize('PnnP4Pnn')
+        self.extra = struct.calcsize('PnnP4PNN')
 
     check_sizeof = support.check_sizeof
 
diff --git a/Modules/_elementtree.c b/Modules/_elementtree.c
index cbad0a063bb981..75870ee27fdd62 100644
--- a/Modules/_elementtree.c
+++ b/Modules/_elementtree.c
@@ -231,9 +231,9 @@ typedef struct {
     PyObject* _children[STATIC_CHILDREN];
 
     /* incremented whenever 'attrib' is externally mutated */
-    uint64_t attrib_version;
+    size_t attrib_version;
     /* incremented whenever children are externally mutated */
-    uint64_t version;
+    size_t version;
 } ElementObjectExtra;
 
 typedef struct {

From a1950d1d4b1ac24ddf849623e8da03bad8191fd2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?B=C3=A9n=C3=A9dikt=20Tran?=
 <10796600+picnixz@users.noreply.github.com>
Date: Mon, 28 Oct 2024 11:49:21 +0100
Subject: [PATCH 4/5] fixup

---
 Modules/_elementtree.c | 34 +++++++++++++++-------------------
 1 file changed, 15 insertions(+), 19 deletions(-)

diff --git a/Modules/_elementtree.c b/Modules/_elementtree.c
index 75870ee27fdd62..11fee5c911422e 100644
--- a/Modules/_elementtree.c
+++ b/Modules/_elementtree.c
@@ -231,9 +231,9 @@ typedef struct {
     PyObject* _children[STATIC_CHILDREN];
 
     /* incremented whenever 'attrib' is externally mutated */
-    size_t attrib_version;
+    size_t attrs_version;
     /* incremented whenever children are externally mutated */
-    size_t version;
+    size_t nodes_version;
 } ElementObjectExtra;
 
 typedef struct {
@@ -283,8 +283,8 @@ create_extra(ElementObject* self, PyObject* attrib)
     self->extra->allocated = STATIC_CHILDREN;
     self->extra->children = self->extra->_children;
 
-    self->extra->attrib_version = 0;
-    self->extra->version = 0;
+    self->extra->attrs_version = 0;
+    self->extra->nodes_version = 0;
 
     return 0;
 }
@@ -513,7 +513,7 @@ element_resize(ElementObject* self, Py_ssize_t extra)
         }
         self->extra->children = children;
         self->extra->allocated = size;
-        self->extra->version++;
+        self->extra->nodes_version++;
     }
 
     return 0;
@@ -547,7 +547,7 @@ element_add_subelement(elementtreestate *st, ElementObject *self,
     self->extra->children[self->extra->length] = Py_NewRef(element);
 
     self->extra->length++;
-    self->extra->version++;
+    self->extra->nodes_version++;
 
     return 0;
 }
@@ -789,7 +789,7 @@ _elementtree_Element___copy___impl(ElementObject *self, PyTypeObject *cls)
 
         assert(!element->extra->length);
         element->extra->length = self->extra->length;
-        element->extra->version = self->extra->version;
+        element->extra->nodes_version = self->extra->nodes_version;
     }
 
     return (PyObject*) element;
@@ -873,7 +873,7 @@ _elementtree_Element___deepcopy___impl(ElementObject *self, PyObject *memo)
 
         assert(!element->extra->length);
         element->extra->length = self->extra->length;
-        element->extra->version = 0;
+        element->extra->nodes_version = 0;
     }
 
     /* add object to memo dictionary (so deepcopy won't visit it again) */
@@ -1029,12 +1029,10 @@ element_setstate_from_attributes(elementtreestate *st,
 
     Py_XSETREF(self->tag, Py_NewRef(tag));
 
-    // TODO(picnix): determine how versioning would work with an evil text
     text = text ? JOIN_SET(text, PyList_CheckExact(text)) : Py_None;
     Py_INCREF(JOIN_OBJ(text));
     _set_joined_ptr(&self->text, text);
 
-    // TODO(picnix): determine how versioning would work with an evil tail
     tail = tail ? JOIN_SET(tail, PyList_CheckExact(tail)) : Py_None;
     Py_INCREF(JOIN_OBJ(tail));
     _set_joined_ptr(&self->tail, tail);
@@ -1085,7 +1083,6 @@ element_setstate_from_attributes(elementtreestate *st,
 
         assert(!self->extra->length);
         self->extra->length = nchildren;
-        self->extra->version++;
     }
     else {
         if (element_resize(self, 0)) {
@@ -1095,7 +1092,6 @@ element_setstate_from_attributes(elementtreestate *st,
 
     /* Stash attrib. */
     Py_XSETREF(self->extra->attrib, Py_XNewRef(attrib));
-    self->extra->attrib_version++;
     dealloc_extra(oldextra);
 
     Py_RETURN_NONE;
@@ -1564,7 +1560,7 @@ _elementtree_Element_insert_impl(ElementObject *self, Py_ssize_t index,
     self->extra->children[index] = Py_NewRef(subelement);
 
     self->extra->length++;
-    self->extra->version++;
+    self->extra->nodes_version++;
 
     Py_RETURN_NONE;
 }
@@ -1687,7 +1683,7 @@ _elementtree_Element_remove_impl(ElementObject *self, PyObject *subelement)
     self->extra->length--;
     for (; i < self->extra->length; i++)
         self->extra->children[i] = self->extra->children[i+1];
-    self->extra->version++;
+    self->extra->nodes_version++;
 
     Py_DECREF(found);
     Py_RETURN_NONE;
@@ -1743,7 +1739,7 @@ _elementtree_Element_set_impl(ElementObject *self, PyObject *key,
     if (PyDict_SetItem(attrib, key, value) < 0)
         return NULL;
 
-    self->extra->attrib_version++;
+    self->extra->attrs_version++;
     Py_RETURN_NONE;
 }
 
@@ -1777,7 +1773,7 @@ element_setitem(PyObject* self_, Py_ssize_t index, PyObject* item)
             self->extra->children[i] = self->extra->children[i+1];
     }
 
-    self->extra->version++;
+    self->extra->nodes_version++;
     Py_DECREF(old);
 
     return 0;
@@ -1928,7 +1924,7 @@ element_ass_subscr(PyObject* self_, PyObject* item, PyObject* value)
             }
 
             self->extra->length -= slicelen;
-            self->extra->version++;
+            self->extra->nodes_version++;
 
             /* Discard the recycle list with all the deleted sub-elements */
             Py_DECREF(recycle);
@@ -2004,7 +2000,7 @@ element_ass_subscr(PyObject* self_, PyObject* item, PyObject* value)
         }
 
         self->extra->length += newlen - slicelen;
-        self->extra->version++;
+        self->extra->nodes_version++;
 
         Py_DECREF(seq);
 
@@ -2101,7 +2097,7 @@ element_attrib_setter(ElementObject *self, PyObject *value, void *closure)
             return -1;
     }
     Py_XSETREF(self->extra->attrib, Py_NewRef(value));
-    self->extra->attrib_version++;
+    self->extra->attrs_version++;
     return 0;
 }
 

From 9b6f55970711d78423ca44c522f6d8e8b93ff0cd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?B=C3=A9n=C3=A9dikt=20Tran?=
 <10796600+picnixz@users.noreply.github.com>
Date: Tue, 29 Oct 2024 09:05:31 +0100
Subject: [PATCH 5/5] unify versioning

---
 Lib/test/test_xml_etree_c.py |  2 +-
 Modules/_elementtree.c       | 31 ++++++++++++++-----------------
 2 files changed, 15 insertions(+), 18 deletions(-)

diff --git a/Lib/test/test_xml_etree_c.py b/Lib/test/test_xml_etree_c.py
index aa95753fed2a49..aae8c3b0019951 100644
--- a/Lib/test/test_xml_etree_c.py
+++ b/Lib/test/test_xml_etree_c.py
@@ -234,7 +234,7 @@ class SizeofTest(unittest.TestCase):
     def setUp(self):
         self.elementsize = support.calcobjsize('5P')
         # extra
-        self.extra = struct.calcsize('PnnP4PNN')
+        self.extra = struct.calcsize('PnnP4PN')
 
     check_sizeof = support.check_sizeof
 
diff --git a/Modules/_elementtree.c b/Modules/_elementtree.c
index 11fee5c911422e..3e206aa4318eee 100644
--- a/Modules/_elementtree.c
+++ b/Modules/_elementtree.c
@@ -230,10 +230,8 @@ typedef struct {
 
     PyObject* _children[STATIC_CHILDREN];
 
-    /* incremented whenever 'attrib' is externally mutated */
-    size_t attrs_version;
-    /* incremented whenever children are externally mutated */
-    size_t nodes_version;
+    /* incremented whenever the object is externally mutated */
+    size_t version;
 } ElementObjectExtra;
 
 typedef struct {
@@ -283,8 +281,7 @@ create_extra(ElementObject* self, PyObject* attrib)
     self->extra->allocated = STATIC_CHILDREN;
     self->extra->children = self->extra->_children;
 
-    self->extra->attrs_version = 0;
-    self->extra->nodes_version = 0;
+    self->extra->version = 0;
 
     return 0;
 }
@@ -513,7 +510,7 @@ element_resize(ElementObject* self, Py_ssize_t extra)
         }
         self->extra->children = children;
         self->extra->allocated = size;
-        self->extra->nodes_version++;
+        self->extra->version++;
     }
 
     return 0;
@@ -547,7 +544,7 @@ element_add_subelement(elementtreestate *st, ElementObject *self,
     self->extra->children[self->extra->length] = Py_NewRef(element);
 
     self->extra->length++;
-    self->extra->nodes_version++;
+    self->extra->version++;
 
     return 0;
 }
@@ -789,7 +786,7 @@ _elementtree_Element___copy___impl(ElementObject *self, PyTypeObject *cls)
 
         assert(!element->extra->length);
         element->extra->length = self->extra->length;
-        element->extra->nodes_version = self->extra->nodes_version;
+        element->extra->version = self->extra->version;
     }
 
     return (PyObject*) element;
@@ -873,7 +870,7 @@ _elementtree_Element___deepcopy___impl(ElementObject *self, PyObject *memo)
 
         assert(!element->extra->length);
         element->extra->length = self->extra->length;
-        element->extra->nodes_version = 0;
+        element->extra->version = 0;
     }
 
     /* add object to memo dictionary (so deepcopy won't visit it again) */
@@ -1560,7 +1557,7 @@ _elementtree_Element_insert_impl(ElementObject *self, Py_ssize_t index,
     self->extra->children[index] = Py_NewRef(subelement);
 
     self->extra->length++;
-    self->extra->nodes_version++;
+    self->extra->version++;
 
     Py_RETURN_NONE;
 }
@@ -1683,7 +1680,7 @@ _elementtree_Element_remove_impl(ElementObject *self, PyObject *subelement)
     self->extra->length--;
     for (; i < self->extra->length; i++)
         self->extra->children[i] = self->extra->children[i+1];
-    self->extra->nodes_version++;
+    self->extra->version++;
 
     Py_DECREF(found);
     Py_RETURN_NONE;
@@ -1739,7 +1736,7 @@ _elementtree_Element_set_impl(ElementObject *self, PyObject *key,
     if (PyDict_SetItem(attrib, key, value) < 0)
         return NULL;
 
-    self->extra->attrs_version++;
+    self->extra->version++;
     Py_RETURN_NONE;
 }
 
@@ -1773,7 +1770,7 @@ element_setitem(PyObject* self_, Py_ssize_t index, PyObject* item)
             self->extra->children[i] = self->extra->children[i+1];
     }
 
-    self->extra->nodes_version++;
+    self->extra->version++;
     Py_DECREF(old);
 
     return 0;
@@ -1924,7 +1921,7 @@ element_ass_subscr(PyObject* self_, PyObject* item, PyObject* value)
             }
 
             self->extra->length -= slicelen;
-            self->extra->nodes_version++;
+            self->extra->version++;
 
             /* Discard the recycle list with all the deleted sub-elements */
             Py_DECREF(recycle);
@@ -2000,7 +1997,7 @@ element_ass_subscr(PyObject* self_, PyObject* item, PyObject* value)
         }
 
         self->extra->length += newlen - slicelen;
-        self->extra->nodes_version++;
+        self->extra->version++;
 
         Py_DECREF(seq);
 
@@ -2097,7 +2094,7 @@ element_attrib_setter(ElementObject *self, PyObject *value, void *closure)
             return -1;
     }
     Py_XSETREF(self->extra->attrib, Py_NewRef(value));
-    self->extra->attrs_version++;
+    self->extra->version++;
     return 0;
 }