Build the Python extension with PY_SSIZE_T_CLEAN

Backport the fix:
https://gitlab.gnome.org/GNOME/libxml2/-/merge_requests/87

Remove files generated files by python/generator.py to always
regenerate them.

Resolves: rhbz#1890878

libxml2.spec

@@ -1,6 +1,6 @@
 Name:           libxml2
 Version:        2.9.10
-Release:        8%{?dist}
+Release:        9%{?dist}
 Summary:        Library providing XML and HTML support
 
 License:        MIT
@@ -20,6 +20,8 @@ Patch5:         libxml2-2.9.10-parenthesize-type-checks.patch
 Patch6:         libxml2-2.9.10-fix-integer-overflow.patch
 # https://bugzilla.redhat.com/show_bug.cgi?id=1877788
 Patch7:         libxml2-2.9.10-CVE-2020-24977.patch
+# https://gitlab.gnome.org/GNOME/libxml2/-/merge_requests/87
+Patch8:         python-py_ssize_t.patch
 
 BuildRequires:  gcc
 BuildRequires:  make
@@ -84,6 +86,9 @@ at parse time or later once the document has been modified.
 %autosetup -p1
 find doc -type f -executable -print -exec chmod 0644 {} ';'
 
+# Remove files generated by python/generator.py to force regenerating them
+rm python/{libxml2-py.c,libxml2-py.h,libxml2-export.c}
+
 %build
 mkdir py3
 %global _configure ../configure
@@ -148,6 +153,11 @@ gzip -9 -c doc/libxml2-api.xml > doc/libxml2-api.xml.gz
 %{python3_sitearch}/libxml2mod.so
 
 %changelog
+* Thu Nov 12 11:57:41 CET 2020 Victor Stinner <vstinner@python.org> - 2.9.10-9
+- Build the Python extension with the PY_SSIZE_T_CLEAN macro to make it
+  compatible with Python 3.10.
+- Fixes: rhbz#1890878.
+
 * Wed Nov 11 2020 Richard W.M. Jones <rjones@redhat.com> - 2.9.10-8
 - Add correct fix for CVE-2020-24977 (RHBZ#1877788), thanks: Jan de Groot.
 

python-py_ssize_t.patch

@@ -0,0 +1,102 @@
+From 43e946dd497cc6ff0067b8a8f85c620376dfd4cd Mon Sep 17 00:00:00 2001
+From: Victor Stinner <vstinner@python.org>
+Date: Mon, 9 Nov 2020 18:19:31 +0100
+Subject: [PATCH 1/2] Build the Python extension with PY_SSIZE_T_CLEAN
+
+The Python extension module now uses Py_ssize_t rather than int for
+string lengths. This change makes the extension compatible with
+Python 3.10.
+
+Fixes #203.
+---
+ python/generator.py | 3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+From b3db67629465823f042a5f3303ecdf8e4bd09a76 Mon Sep 17 00:00:00 2001
+From: Victor Stinner <vstinner@python.org>
+Date: Tue, 10 Nov 2020 15:42:36 +0100
+Subject: [PATCH 2/2] Convert python/libxml.c to PY_SSIZE_T_CLEAN
+
+Define PY_SSIZE_T_CLEAN macro in python/libxml.c and cast the string
+length (int len) explicitly to Py_ssize_t when passing a string to a
+function call using PyObject_CallMethod() with the "s#" format.
+---
+ python/libxml.c | 13 +++++++------
+ 1 file changed, 7 insertions(+), 6 deletions(-)
+
+diff --git a/python/generator.py b/python/generator.py
+index c0cb3add..59d45e00 100755
+--- a/python/generator.py
++++ b/python/generator.py
+@@ -393,7 +393,7 @@ def print_function_wrapper(name, output, export, include):
+                 format_args = format_args + ", &%s" % (arg[0])
+             if f == 's#':
+                 format_args = format_args + ", &py_buffsize%d" % num_bufs
+-                c_args = c_args + "    int py_buffsize%d;\n" % num_bufs
++                c_args = c_args + "    Py_ssize_t  py_buffsize%d;\n" % num_bufs
+                 num_bufs = num_bufs + 1
+             if c_call != "":
+                 c_call = c_call + ", "
+@@ -555,6 +555,7 @@ def buildStubs():
+     export.write("/* Generated */\n\n")
+     wrapper = open("libxml2-py.c", "w")
+     wrapper.write("/* Generated */\n\n")
++    wrapper.write("#define PY_SSIZE_T_CLEAN\n")
+     wrapper.write("#include <Python.h>\n")
+     wrapper.write("#include <libxml/xmlversion.h>\n")
+     wrapper.write("#include <libxml/tree.h>\n")
+diff --git a/python/libxml.c b/python/libxml.c
+index 81e709f3..3b66bd61 100644
+--- a/python/libxml.c
++++ b/python/libxml.c
+@@ -11,6 +11,7 @@
+  *
+  * daniel@veillard.com
+  */
++#define PY_SSIZE_T_CLEAN
+ #include <Python.h>
+ #include <fileobject.h>
+ /* #include "config.h" */
+@@ -1048,10 +1049,10 @@ pythonCharacters(void *user_data, const xmlChar * ch, int len)
+     if (type != 0) {
+         if (type == 1)
+             result = PyObject_CallMethod(handler, (char *) "characters",
+-                                         (char *) "s#", ch, len);
++                                         (char *) "s#", ch, (Py_ssize_t)len);
+         else if (type == 2)
+             result = PyObject_CallMethod(handler, (char *) "data",
+-                                         (char *) "s#", ch, len);
++                                         (char *) "s#", ch, (Py_ssize_t)len);
+         if (PyErr_Occurred())
+             PyErr_Print();
+         Py_XDECREF(result);
+@@ -1078,11 +1079,11 @@ pythonIgnorableWhitespace(void *user_data, const xmlChar * ch, int len)
+             result =
+                 PyObject_CallMethod(handler,
+                                     (char *) "ignorableWhitespace",
+-                                    (char *) "s#", ch, len);
++                                    (char *) "s#", ch, (Py_ssize_t)len);
+         else if (type == 2)
+             result =
+                 PyObject_CallMethod(handler, (char *) "data",
+-                                    (char *) "s#", ch, len);
++                                    (char *) "s#", ch, (Py_ssize_t)len);
+         Py_XDECREF(result);
+     }
+ }
+@@ -1223,11 +1224,11 @@ pythonCdataBlock(void *user_data, const xmlChar * ch, int len)
+         if (type == 1)
+             result =
+                 PyObject_CallMethod(handler, (char *) "cdataBlock",
+-                                    (char *) "s#", ch, len);
++                                    (char *) "s#", ch, (Py_ssize_t)len);
+         else if (type == 2)
+             result =
+                 PyObject_CallMethod(handler, (char *) "cdata",
+-                                    (char *) "s#", ch, len);
++                                    (char *) "s#", ch, (Py_ssize_t)len);
+         if (PyErr_Occurred())
+             PyErr_Print();
+         Py_XDECREF(result);
+-- 
+2.26.2