cli(stop,new,copy,delete[help]): Show help when called with no arguments

why: These commands showed a terse argparse error on missing args instead
of the full subcommand help page, unlike the search command.
what:
- Make positional args optional via nargs="?"/"*" in subparser setup
- Stash subparser print_help via set_defaults for dispatch access
- Add no-args guards in cli() dispatch using args.print_help()
- Add parametrized test for all four commands

Author: tony

src/tmuxp/cli/__init__.py

@@ -420,19 +420,28 @@ def cli(_args: list[str] | None = None) -> None:
             color=args.color,
         )
     elif args.subparser_name == "new":
+        if not args.workspace_name:
+            args.print_help()
+            return
         command_new(
             workspace_name=args.workspace_name,
             parser=parser,
             color=args.color,
         )
     elif args.subparser_name == "copy":
+        if not args.source or not args.destination:
+            args.print_help()
+            return
         command_copy(
             source=args.source,
             destination=args.destination,
             parser=parser,
             color=args.color,
         )
     elif args.subparser_name == "delete":
+        if not args.workspace_names:
+            args.print_help()
+            return
         command_delete(
             workspace_names=args.workspace_names,
             answer_yes=args.answer_yes,
@@ -445,6 +454,9 @@ def cli(_args: list[str] | None = None) -> None:
             parser=parser,
         )
     elif args.subparser_name == "stop":
+        if not args.session_name:
+            args.print_help()
+            return
         command_stop(
             args=CLIStopNamespace(**vars(args)),
             parser=parser,

src/tmuxp/cli/copy.py

@@ -52,19 +52,30 @@ def create_copy_subparser(
     >>> args = parser.parse_args(["src", "dst"])
     >>> args.source, args.destination
     ('src', 'dst')
+
+    No arguments yields ``None``:
+
+    >>> args = parser.parse_args([])
+    >>> args.source is None and args.destination is None
+    True
     """
     parser.add_argument(
         dest="source",
         metavar="source",
+        nargs="?",
+        default=None,
         type=str,
         help="source workspace name or file path.",
     )
     parser.add_argument(
         dest="destination",
         metavar="destination",
+        nargs="?",
+        default=None,
         type=str,
         help="destination workspace name or file path.",
     )
+    parser.set_defaults(print_help=parser.print_help)
     return parser
 
 

src/tmuxp/cli/delete.py

@@ -53,11 +53,17 @@ def create_delete_subparser(
     ['proj1', 'proj2']
     >>> args.answer_yes
     True
+
+    No arguments yields an empty list:
+
+    >>> args = parser.parse_args([])
+    >>> args.workspace_names
+    []
     """
     parser.add_argument(
         dest="workspace_names",
         metavar="workspace-name",
-        nargs="+",
+        nargs="*",
         type=str,
         help="workspace name(s) or file path(s) to delete.",
     )
@@ -68,6 +74,7 @@ def create_delete_subparser(
         action="store_true",
         help="skip confirmation prompt.",
     )
+    parser.set_defaults(print_help=parser.print_help)
     return parser
 
 

src/tmuxp/cli/new.py

@@ -59,13 +59,22 @@ def create_new_subparser(
     >>> args = parser.parse_args(["myproject"])
     >>> args.workspace_name
     'myproject'
+
+    No arguments yields ``None``:
+
+    >>> args = parser.parse_args([])
+    >>> args.workspace_name is None
+    True
     """
     parser.add_argument(
         dest="workspace_name",
         metavar="workspace-name",
+        nargs="?",
+        default=None,
         type=str,
         help="name for the new workspace config.",
     )
+    parser.set_defaults(print_help=parser.print_help)
     return parser
 
 

src/tmuxp/cli/stop.py

@@ -75,6 +75,7 @@ def create_stop_subparser(
         metavar="socket-name",
         help="pass-through for tmux -L",
     )
+    parser.set_defaults(print_help=parser.print_help)
     return parser
 
 

tests/cli/test_help_examples.py

@@ -300,6 +300,18 @@ def test_search_no_args_shows_help() -> None:
     assert result.returncode == 0
 
 
+@pytest.mark.parametrize("subcommand", ["stop", "new", "copy", "delete"])
+def test_new_commands_no_args_shows_help(subcommand: str) -> None:
+    """Running new commands with no args shows help."""
+    result = subprocess.run(
+        ["tmuxp", subcommand],
+        capture_output=True,
+        text=True,
+    )
+    assert f"usage: tmuxp {subcommand}" in result.stdout
+    assert result.returncode == 0
+
+
 def test_main_help_example_sections_have_examples_suffix() -> None:
     """Main --help should have section headings ending with 'examples:'."""
     help_text = _get_help_text()