gh-131852: Filter out POT-Creation-Date in msgfmt

Lib/test/test_tools/msgfmt_data/general.json

@@ -1,7 +1,7 @@
 [
     [
         "",
-        "Project-Id-Version: PACKAGE VERSION\nPOT-Creation-Date: 2024-10-26 18:06+0200\nPO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\nLast-Translator: FULL NAME <EMAIL@ADDRESS>\nLanguage-Team: LANGUAGE <LL@li.org>\nMIME-Version: 1.0\nContent-Type: text/plain; charset=UTF-8\nContent-Transfer-Encoding: 8bit\n"
+        "Project-Id-Version: PACKAGE VERSION\nPO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\nLast-Translator: FULL NAME <EMAIL@ADDRESS>\nLanguage-Team: LANGUAGE <LL@li.org>\nMIME-Version: 1.0\nContent-Type: text/plain; charset=UTF-8\nContent-Transfer-Encoding: 8bit\n"
     ],
     [
         "\n newlines \n",

Misc/NEWS.d/next/Tools-Demos/2025-03-29-16-20-00.gh-issue-131852.afuefb.rst

@@ -0,0 +1,2 @@
+:program:`msgfmt` no longer adds the ``POT-Creation-Date`` to generated ``.mo`` files
+for consistency with GNU ``msgfmt``.

Tools/i18n/msgfmt.py

@@ -158,14 +158,19 @@ def make(filename, outfile):
             msgctxt = b''
         elif l.startswith('msgid') and not l.startswith('msgid_plural'):
             if section == STR:
-                add(msgctxt, msgid, msgstr, fuzzy)
-                msgctxt = None
                 if not msgid:
+                    # Filter out POT-Creation-Date
+                    # See issue #131852
+                    msgstr = b''.join(line for line in msgstr.splitlines(True)
+                                      if not line.startswith(b'POT-Creation-Date'))
+
                     # See whether there is an encoding declaration
                     p = HeaderParser()
                     charset = p.parsestr(msgstr.decode(encoding)).get_content_charset()
                     if charset:
                         encoding = charset
+                add(msgctxt, msgid, msgstr, fuzzy)
+                msgctxt = None
             section = ID
             l = l[5:]
             msgid = msgstr = b''