gh-130647: Add --omit-header option to pygettext

Lib/test/test_tools/test_i18n.py

@@ -516,6 +516,22 @@ def test_parse_keyword_spec(self):
                     parse_spec(spec)
                 self.assertEqual(str(cm.exception), message)
 
+    def test_omit_header(self):
+        """Test that --omit-header removes the header."""
+        data = self.extract_from_str(dedent('''\
+        _("foo")
+        '''), args=('--omit-header',), raw=True)
+
+        self.assertNotIn("Project-Id-Version", data)
+        self.assertNotIn("POT-Creation-Date", data)
+        self.assertNotIn("PO-Revision-Date", data)
+        self.assertNotIn("Last-Translator", data)
+        self.assertNotIn("Language-Team", data)
+        self.assertNotIn("MIME-Version", data)
+        self.assertNotIn("Content-Type", data)
+        self.assertNotIn("Content-Transfer-Encoding", data)
+        self.assertNotIn("Generated-By", data)
+
 
 def extract_from_snapshots():
     snapshots = {

Misc/NEWS.d/next/Tools-Demos/2025-02-27-19-00-00.gh-issue-130647.uwda2h.rst

@@ -0,0 +1 @@
+Add ``--omit-header`` option to :program:`pygettext`.

Tools/i18n/pygettext.py

@@ -124,6 +124,15 @@
     --width=columns
         Set width of output to columns.
 
+    --omit-header
+        Don’t write header to file.
+
+        This is useful for testing purposes because it eliminates a source of
+        variance for generated .gmo files.
+
+        Note: Using this option will lead to an error if the resulting file
+        would not entirely be in ASCII.
+
     -x filename
     --exclude-file=filename
         Specify a file that contains a list of strings that are not be
@@ -574,9 +583,11 @@ def _is_string_const(self, node):
 def write_pot_file(messages, options, fp):
     timestamp = time.strftime('%Y-%m-%d %H:%M%z')
     encoding = fp.encoding if fp.encoding else 'UTF-8'
-    print(pot_header % {'time': timestamp, 'version': __version__,
-                        'charset': encoding,
-                        'encoding': '8bit'}, file=fp)
+
+    if not options.omit_header:
+        print(pot_header % {'time': timestamp, 'version': __version__,
+                            'charset': encoding,
+                            'encoding': '8bit'}, file=fp)
 
     # Sort locations within each message by filename and lineno
     sorted_keys = [
@@ -636,7 +647,7 @@ def main():
             ['extract-all', 'add-comments=?', 'default-domain=', 'escape',
              'help', 'keyword=', 'no-default-keywords',
              'add-location', 'no-location', 'output=', 'output-dir=',
-             'style=', 'verbose', 'version', 'width=', 'exclude-file=',
+             'style=', 'verbose', 'version', 'width=', 'omit-header', 'exclude-file=',
              'docstrings', 'no-docstrings',
              ])
     except getopt.error as msg:
@@ -657,6 +668,7 @@ class Options:
         locationstyle = GNU
         verbose = 0
         width = 78
+        omit_header = False
         excludefilename = ''
         docstrings = 0
         nodocstrings = {}
@@ -709,6 +721,8 @@ class Options:
                 options.width = int(arg)
             except ValueError:
                 usage(1, f'--width argument must be an integer: {arg}')
+        elif opt in ('--omit-header',):
+            options.omit_header = True
         elif opt in ('-x', '--exclude-file'):
             options.excludefilename = arg
         elif opt in ('-X', '--no-docstrings'):