From 8a6c2dc7ff0c6d58f2cf9a97c32a91b52f9a72d2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Sch=C3=BCrmann?= <daschuer@mixxx.org>
Date: Sun, 29 Dec 2024 12:29:44 +0100
Subject: [PATCH] Add a script that reverts changes in po files when only the
 time stamp has changed It helps to create meaningful commits, instead of up
 to 4100 changed files.

---
 .pre-commit-config.yaml           |  5 ++
 tools/ignore_pot_creation_date.py | 96 +++++++++++++++++++++++++++++++
 2 files changed, 101 insertions(+)
 create mode 100644 tools/ignore_pot_creation_date.py

diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 7ead829348..432931e853 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -15,6 +15,11 @@ repos:
     types: [rst]
     entry: python tools/fixup_gh_wiki_anchors.py
     language: python
+  - id: ignore-pot-creation-date
+    name: Ignore POT-Creation-Date
+    entry: python tools/ignore_pot_creation_date.py
+    language: python
+    files: ^.*\.po$
 - repo: https://github.com/pre-commit/pre-commit-hooks
   rev: v3.1.0
   hooks:
diff --git a/tools/ignore_pot_creation_date.py b/tools/ignore_pot_creation_date.py
new file mode 100644
index 0000000000..6e8a8c38c2
--- /dev/null
+++ b/tools/ignore_pot_creation_date.py
@@ -0,0 +1,96 @@
+import argparse
+import logging
+import os
+import subprocess
+import sys
+import typing
+
+"""
+This script reverts changes in PO files when only the timestamp has changed.
+It helps to create meaningful commits by ignoring unnecessary changes.
+"""
+
+
+def get_git_changeset(from_ref, to_ref) -> str:
+    """
+    Constructs the changeset string for `git diff` based on from_ref and
+    to_ref.
+    """
+    from_ref = (
+        from_ref
+        or os.getenv("PRE_COMMIT_FROM_REF")
+        or os.getenv("PRE_COMMIT_SOURCE")
+        or "HEAD"
+    )
+    to_ref = (
+        to_ref
+        or os.getenv("PRE_COMMIT_TO_REF")
+        or os.getenv("PRE_COMMIT_ORIGIN")
+    )
+    return f"{from_ref}...{to_ref}" if to_ref else from_ref
+
+
+def count_meaningful_changes(changeset, po_file) -> int:
+    """
+    Counts meaningful changes in the diff for a given PO file.
+    """
+    cmd = ["git", "diff", "--patch", "--unified=0", changeset, "--", po_file]
+    proc = subprocess.run(cmd, capture_output=True, text=True)
+    proc.check_returncode()
+
+    diff_lines = proc.stdout.splitlines()
+    return sum(
+        1
+        for line in diff_lines
+        if (line.startswith("-") or line.startswith("+"))
+        and "POT-Creation-Date:" not in line
+        and "PO-Revision-Date:" not in line
+        and po_file not in line
+    )
+
+
+def revert_po_file(changeset, po_file, logger):
+    """
+    Reverts a PO file to its original state in the given changeset.
+    """
+    ref = changeset.split("...")[
+        0
+    ]  # Use the first part of the changeset as the reference
+    logger.info(f"{po_file} has no meaningful changes, reverting to {ref}")
+    cmd = ["git", "show", f"{ref}:{po_file}"]
+    proc = subprocess.run(cmd, capture_output=True, text=True)
+    proc.check_returncode()
+
+    with open(po_file, "w") as file:
+        file.write(proc.stdout)
+
+
+def main(argv: typing.Optional[typing.List[str]] = None) -> int:
+    logging.basicConfig(
+        format="[%(levelname)s] %(message)s", level=logging.INFO
+    )
+    logger = logging.getLogger(__name__)
+
+    parser = argparse.ArgumentParser(
+        description="Revert PO files with only timestamp changes."
+    )
+    parser.add_argument("--from-ref", help="Use changes since this commit.")
+    parser.add_argument("--to-ref", help="Use changes until this commit.")
+    parser.add_argument("files", nargs="*", help="Only check these files.")
+    args = parser.parse_args(argv)
+
+    # Remove the first entry which is the script file name itself
+    files_to_process = args.files[1:] if args.files else []
+
+    changeset = get_git_changeset(args.from_ref, args.to_ref)
+
+    for po_file in files_to_process:
+        count = count_meaningful_changes(changeset, po_file)
+        if count == 0:
+            revert_po_file(changeset, po_file, logger)
+
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())