gh-139873: pygettext: Open files with encoding='utf-8'

Lib/test/test_tools/test_i18n.py

@@ -591,6 +591,22 @@ def test_multiple_keywords_same_funcname_errors(self):
             '\tkeyword="_": Expected a string constant for argument 1, got 42\n'
             '\tkeyword="_:2": Expected a string constant for argument 2, got y\n')
 
+    def test_utf8_encoding(self):
+        with temp_cwd(None):
+            with open('test.py', 'w', encoding='utf-8') as fp:
+                fp.write('_("áscii")')
+
+            res = assert_python_ok(self.script,
+                                   'test.py',
+                                   PYTHONCOERCECLOCALE="0",
+                                   PYTHONUTF8="0",
+                                   LANG="C",
+                                   LC_ALL="C")
+            self.assertEqual(res.err, b'')
+
+            with open('messages.pot', encoding='utf-8') as fp:
+                pot_content = fp.read()
+            self.assertIn('áscii', pot_content)
 
 def extract_from_snapshots():
     snapshots = {

Misc/NEWS.d/next/Tools-Demos/2025-10-10-18-07-18.gh-issue-139873.aVALQm.rst

@@ -0,0 +1 @@
+:program:`pygettext`: open files with the uft-8 encoding

Tools/i18n/pygettext.py

@@ -767,7 +767,7 @@ class Options:
         elif opt in ('-x', '--exclude-file'):
             options.excludefilename = arg
         elif opt in ('-X', '--no-docstrings'):
-            fp = open(arg)
+            fp = open(arg, encoding='utf-8')
             try:
                 while 1:
                     line = fp.readline()
@@ -794,7 +794,7 @@ class Options:
     # initialize list of strings to exclude
     if options.excludefilename:
         try:
-            with open(options.excludefilename) as fp:
+            with open(options.excludefilename, encoding='utf-8') as fp:
                 options.toexclude = fp.readlines()
         except OSError:
             print(f"Can't read --exclude-file: {options.excludefilename}",
@@ -834,7 +834,7 @@ class Options:
     else:
         if options.outpath:
             options.outfile = os.path.join(options.outpath, options.outfile)
-        fp = open(options.outfile, 'w')
+        fp = open(options.outfile, 'w', encoding='utf-8')
         closep = 1
     try:
         write_pot_file(visitor.messages, options, fp)