From 6278bb5c2edfea83bf4fc7bd1eb8c4ee946cbca0 Mon Sep 17 00:00:00 2001
From: maurycy <5383+maurycy@users.noreply.github.com>
Date: Sat, 4 Apr 2026 00:34:42 +0200
Subject: [PATCH 1/4] banal fix

---
 Modules/_elementtree.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Modules/_elementtree.c b/Modules/_elementtree.c
index e2185c4bd03aad..9b0dea741aba7e 100644
--- a/Modules/_elementtree.c
+++ b/Modules/_elementtree.c
@@ -3699,6 +3699,8 @@ ignore_attribute_error(PyObject *value)
     return 0;
 }
 
+static int xmlparser_gc_clear(PyObject *op);
+
 /*[clinic input]
 _elementtree.XMLParser.__init__
 
@@ -3713,6 +3715,10 @@ _elementtree_XMLParser___init___impl(XMLParserObject *self, PyObject *target,
                                      const char *encoding)
 /*[clinic end generated code: output=3ae45ec6cdf344e4 input=7e716dd6e4f3e439]*/
 {
+    if (self->parser != NULL) {
+        (void)xmlparser_gc_clear((PyObject *)self);
+    }
+
     self->entity = PyDict_New();
     if (!self->entity)
         return -1;

From cc94cb191ee1296b29c0348da036ad37e75a45ab Mon Sep 17 00:00:00 2001
From: maurycy <5383+maurycy@users.noreply.github.com>
Date: Sat, 4 Apr 2026 00:37:42 +0200
Subject: [PATCH 2/4] news

---
 .../Library/2026-04-04-00-37-39.gh-issue-148058.zMIVaS.rst     | 3 +++
 1 file changed, 3 insertions(+)
 create mode 100644 Misc/NEWS.d/next/Library/2026-04-04-00-37-39.gh-issue-148058.zMIVaS.rst

diff --git a/Misc/NEWS.d/next/Library/2026-04-04-00-37-39.gh-issue-148058.zMIVaS.rst b/Misc/NEWS.d/next/Library/2026-04-04-00-37-39.gh-issue-148058.zMIVaS.rst
new file mode 100644
index 00000000000000..20b9f36bfe2d2c
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2026-04-04-00-37-39.gh-issue-148058.zMIVaS.rst
@@ -0,0 +1,3 @@
+Fix reference leak in :class:`xml.etree.ElementTree.XMLParser` when
+:meth:`~object.__init__` is called many times. Patch by Maurycy
+Pawłowski-Wieroński.

From 8114c8dfbb6fd30860093fccec5a65fb59d9a31f Mon Sep 17 00:00:00 2001
From: maurycy <5383+maurycy@users.noreply.github.com>
Date: Sat, 4 Apr 2026 00:38:24 +0200
Subject: [PATCH 3/4] test

---
 Lib/test/test_xml_etree_c.py | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/Lib/test/test_xml_etree_c.py b/Lib/test/test_xml_etree_c.py
index 270b9d6da8e7b9..53e3e2ac24e9d3 100644
--- a/Lib/test/test_xml_etree_c.py
+++ b/Lib/test/test_xml_etree_c.py
@@ -1,6 +1,7 @@
 # xml.etree test for cElementTree
 import io
 import struct
+import sys
 from test import support
 from test.support.import_helper import import_fresh_module
 import types
@@ -171,6 +172,15 @@ def test_xmlpullparser_leaks(self):
         del parser
         support.gc_collect()
 
+    @support.refcount_test
+    def test_xmlparser_refleaks_in___init__(self):
+        gettotalrefcount = support.get_attribute(sys, 'gettotalrefcount')
+        parser = cET.XMLParser()
+        refs_before = gettotalrefcount()
+        for _ in range(100):
+            parser.__init__()
+        self.assertAlmostEqual(gettotalrefcount() - refs_before, 0, delta=10)
+
     def test_dict_disappearing_during_get_item(self):
         # test fix for seg fault reported in issue 27946
         class X:

From a49f86212c7a41cc67f1488871df51497d4521e1 Mon Sep 17 00:00:00 2001
From: maurycy <5383+maurycy@users.noreply.github.com>
Date: Sat, 4 Apr 2026 12:08:48 +0200
Subject: [PATCH 4/4] more like test_csv

---
 Lib/test/test_xml_etree_c.py | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/Lib/test/test_xml_etree_c.py b/Lib/test/test_xml_etree_c.py
index 53e3e2ac24e9d3..e9aed652c2a056 100644
--- a/Lib/test/test_xml_etree_c.py
+++ b/Lib/test/test_xml_etree_c.py
@@ -176,10 +176,15 @@ def test_xmlpullparser_leaks(self):
     def test_xmlparser_refleaks_in___init__(self):
         gettotalrefcount = support.get_attribute(sys, 'gettotalrefcount')
         parser = cET.XMLParser()
-        refs_before = gettotalrefcount()
-        for _ in range(100):
-            parser.__init__()
-        self.assertAlmostEqual(gettotalrefcount() - refs_before, 0, delta=10)
+        lastrc = gettotalrefcount()
+        for i in range(20):
+            support.gc_collect()
+            rc = gettotalrefcount()
+            for _ in range(100):
+                parser.__init__()
+            delta = rc - lastrc
+            lastrc = rc
+        self.assertLess(delta, 3)
 
     def test_dict_disappearing_during_get_item(self):
         # test fix for seg fault reported in issue 27946