version-helper: Add script for setting the release date in Cargo.toml

See #599

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs/-/merge_requests/1939>

set-release-date-in-manifest.py

@@ -0,0 +1,37 @@
+#!/usr/bin/env python3
+
+# Set [package.metadata.gstreamer] release_date to the date of the last commit.
+# Failing that, to today.
+
+try:
+    # Python11 stdlib
+    import tomllib
+except ImportError:
+    import tomli as tomllib
+
+from datetime import datetime, timezone
+from pathlib import Path
+import re
+import subprocess
+
+path = Path(__file__).parent
+
+try:
+    release_date = subprocess.check_output(['git', 'show', '-s', '--format=%cd', '--date=short', 'HEAD'], shell=False, cwd=path, stderr=None, text=True).strip()
+except subprocess.CalledProcessError:
+    release_date = datetime.now(timezone.utc).strftime('%Y-%m-%d')
+
+with (path / 'Cargo.toml').open('rb') as f:
+    members = tomllib.load(f)['workspace']['members']
+
+    for lib in members:
+        g = path / lib /'Cargo.toml'
+        manifest = g.open('r', encoding='utf-8').read()
+
+        if 'package.metadata.gstreamer' not in manifest:
+            # add release date
+            manifest += f'\n[package.metadata.gstreamer]\nrelease_date = "{release_date}"\n'
+        else:
+            manifest = re.sub(r'release_date = "[0-9]+-[0-9]+-[0-9]+"', f'release_date = "{release_date}"', manifest)
+
+        g.open('w', encoding='utf-8').write(manifest)