4.2.0 (August 6, 2026)

• Enhancements
  • @with_annotated argument groups can now contain an ArgumentBlock's arguments. A Group member names a command-line argument, and a block expands into one argument per field, so its fields are named: Group("host", "port").
• Breaking Changes
  • A Group member now names an argument rather than a parameter. The two differ only for an ArgumentBlock parameter, which is expanded away and has no argument of its own: Group("conn") now raises ValueError pointing at the block's fields. It previously produced an empty argument group in groups= and a KeyError in mutually_exclusive_groups=.
  • Whether a Group member exists is now validated when the parser is built rather than at decoration time, because a block's field names cannot be known without resolving its type hint, and resolving hints eagerly would break forward-referenced annotations. A typo in a member name still raises ValueError, but on first use of that command rather than at class definition. The spec-shape rules (a member listed twice, a member in two groups, required=True on a plain group, the mutex nesting rules) are unaffected and still hard-fail at decoration time.
• Bug Fixes
  • Fixed @with_annotated(base_command=True) not listing its subcommands under the positional arguments section of the parent command's --help, unlike argparse and Cmd2ArgumentParser. They were placed in an untitled section of their own instead. Passing subcommand_title or subcommand_description still gives the subcommands a dedicated section (#1715).
  • Fix @with_annotated decorator so using ArgumentBlock works with groups (#1718).
  • Fixed bug where already sorted choices_provider results were being re-sorted (#1727).