Enhance translation file management: Add cleanup function to remove volatile headers and prevent merge conflicts

Author: PierreRaybaut

doc/release_notes/release_3.13.md

@@ -1,6 +1,16 @@
 
 # Version 3.13 #
 
+## Version 3.13.5 ##
+
+🛠️ Bug fixes:
+
+* Translation file generation: Ignore POT-Creation-Date and Last-Translator headers to reduce unnecessary diffs
+  * Added `_cleanup_po_file()` helper function to remove the `POT-Creation-Date` and `Last-Translator` headers from generated `.po` files
+  * This prevents spurious diffs in version control when regeneration occurs at different times
+  * Integrated cleanup step into `generate_translation_files()` after `.po` file creation
+  * Ensures cleaner translation file management and reduces noise in commit history
+
 ## Version 3.13.4 (2025-12-03) ##
 
 🛠️ Bug fixes:

guidata/utils/translations.py

@@ -52,12 +52,39 @@
 import argparse
 import locale
 import os
+import re
 import subprocess
 import sys
 import typing
 
 PYBABEL_ARGS = [sys.executable, "-m", "babel.messages.frontend"]
 
+# Header lines to remove from .po files to avoid unnecessary merge conflicts
+# when cherry-picking commits between branches
+PO_HEADERS_TO_REMOVE = [
+    "POT-Creation-Date",
+    "Last-Translator",
+]
+
+
+def _cleanup_po_file(po_file: str) -> None:
+    """Remove volatile header lines from a .po file to avoid merge conflicts.
+
+    Args:
+        po_file: Path to the .po file to clean up.
+    """
+    with open(po_file, "r", encoding="utf-8") as f:
+        content = f.read()
+
+    # Build a regex pattern to match and remove the header lines
+    for header in PO_HEADERS_TO_REMOVE:
+        # Match the header line in the msgstr block (e.g., "POT-Creation-Date: ...\n")
+        pattern = rf'"{header}:[^"]*\\n"\n'
+        content = re.sub(pattern, "", content)
+
+    with open(po_file, "w", encoding="utf-8") as f:
+        f.write(content)
+
 
 def get_default_language_code() -> str:
     """Get the default language code of the system.
@@ -186,9 +213,13 @@ def scan_translations(
                     "--init-missing",
                     "--no-wrap",
                     "--update-header-comment",
+                    "--ignore-pot-creation-date",
                 ],
                 check=True,
             )
+            # Clean up the .po file to remove volatile headers
+            po_file = os.path.join(translation_dir, code, "LC_MESSAGES", f"{name}.po")
+            _cleanup_po_file(po_file)
     except subprocess.CalledProcessError as e:
         print("Error: Translation file generation failed.")
         print(e.stderr)