update: release.py tags a Debian revision other than 1 as x.y.z-n.

release.py

@@ -1,9 +1,9 @@
 #!/usr/bin/env python3
 """Commit everything, tag the version of the newest changelog entry and push main with the tags.
 
-The tag is the upstream version of the first entry of debian-package/debian/changelog,
-without the Debian revision: vpn-router (0.5.1-1) is tagged 0.5.1, which starts the
-release workflow.
+The tag is the version of the first entry of debian-package/debian/changelog, without the
+Debian revision 1: vpn-router (0.5.1-1) is tagged 0.5.1 and (0.5.1-2) 0.5.1-2. The tag
+starts the release workflow.
 """
 
 import argparse
@@ -48,13 +48,14 @@ def summary():
 
 
 def version():
-    """The upstream version of the first changelog entry."""
+    """The tag of the first changelog entry: its version, without the Debian revision when that is 1."""
     first = CHANGELOG.read_text(encoding='utf-8').splitlines()[0]
     start, end = first.find('('), first.find(')')
     if start == -1 or end < start:
         sys.exit(f'{CHANGELOG}: the first line has no version: {first}')
     full = first[start + 1:end]
-    return full.rsplit('-', 1)[0] if '-' in full else full
+    upstream, _, revision = full.rpartition('-')
+    return upstream if upstream and revision == '1' else full
 
 
 def main():