Fixed AttributeError when CommandSet that uses as_subcommand_to decorator is loaded during cmd2.Cmd.__init__().

Author: kmvanbrunt

CHANGELOG.md

@@ -1,3 +1,8 @@
+## 1.3.4 (TBD)
+* Bug Fixes
+    * Fixed `AttributeError` when `CommandSet` that uses `as_subcommand_to` decorator is loaded during
+    `cmd2.Cmd.__init__()`.
+
 ## 1.3.3 (August 13, 2020)
 * Breaking changes
     * CommandSet command functions (do_, complete_, help_) will no longer have the cmd2 app

cmd2/cmd2.py

@@ -259,22 +259,6 @@ def __init__(self, completekey: str = 'tab', stdin=None, stdout=None, *,
                                                 multiline_commands=multiline_commands,
                                                 shortcuts=shortcuts)
 
-        # Load modular commands
-        self._installed_command_sets = []  # type: List[CommandSet]
-        self._cmd_to_command_sets = {}  # type: Dict[str, CommandSet]
-        if command_sets:
-            for command_set in command_sets:
-                self.register_command_set(command_set)
-
-        if auto_load_commands:
-            self._autoload_commands()
-
-        # Verify commands don't have invalid names (like starting with a shortcut)
-        for cur_cmd in self.get_all_commands():
-            valid, errmsg = self.statement_parser.is_valid_command(cur_cmd)
-            if not valid:
-                raise ValueError("Invalid command name {!r}: {}".format(cur_cmd, errmsg))
-
         # Stores results from the last command run to enable usage of results in a Python script or interactive console
         # Built-in commands don't make use of this.  It is purely there for user-defined commands and convenience.
         self.last_result = None
@@ -412,6 +396,28 @@ def __init__(self, completekey: str = 'tab', stdin=None, stdout=None, *,
         # If False, then complete() will sort the matches using self.default_sort_key before they are displayed.
         self.matches_sorted = False
 
+        ############################################################################################################
+        # The following code block loads CommandSets, verifies command names, and registers subcommands.
+        # This block should appear after all attributes have been created since the registration code
+        # depends on them and it's possible a module's on_register() method may need to access some.
+        ############################################################################################################
+        # Load modular commands
+        self._installed_command_sets = []  # type: List[CommandSet]
+        self._cmd_to_command_sets = {}  # type: Dict[str, CommandSet]
+        if command_sets:
+            for command_set in command_sets:
+                self.register_command_set(command_set)
+
+        if auto_load_commands:
+            self._autoload_commands()
+
+        # Verify commands don't have invalid names (like starting with a shortcut)
+        for cur_cmd in self.get_all_commands():
+            valid, errmsg = self.statement_parser.is_valid_command(cur_cmd)
+            if not valid:
+                raise ValueError("Invalid command name {!r}: {}".format(cur_cmd, errmsg))
+
+        # Add functions decorated to be subcommands
         self._register_subcommands(self)
 
     def find_commandsets(self, commandset_type: Type[CommandSet], *, subclass_match: bool = False) -> List[CommandSet]:

tests_isolated/test_commandset/test_commandset.py

@@ -62,6 +62,26 @@ def do_elderberry(self, ns: argparse.Namespace):
         self._cmd.poutput('Elderberry {}!!'.format(ns.arg1))
         self._cmd.last_result = {'arg1': ns.arg1}
 
+    # Test that CommandSet with as_subcommand_to decorator successfully loads
+    # during `cmd2.Cmd.__init__()`.
+    main_parser = cmd2.Cmd2ArgumentParser(description="Main Command")
+    main_subparsers = main_parser.add_subparsers(dest='subcommand', metavar='SUBCOMMAND')
+    main_subparsers.required = True
+
+    @cmd2.with_category('Alone')
+    @cmd2.with_argparser(main_parser)
+    def do_main(self, args: argparse.Namespace) -> None:
+        # Call handler for whatever subcommand was selected
+        handler = args.get_handler()
+        handler(args)
+
+    # main -> sub
+    subcmd_parser = cmd2.Cmd2ArgumentParser(add_help=False, description="Sub Command")
+
+    @cmd2.as_subcommand_to('main', 'sub', subcmd_parser, help="sub command")
+    def subcmd_func(self, args: argparse.Namespace) -> None:
+        self._cmd.poutput("Subcommand Ran")
+
 
 @cmd2.with_default_category('Command Set B')
 class CommandSetB(CommandSetBase):
@@ -87,6 +107,11 @@ def test_autoload_commands(command_sets_app):
 
     assert 'Alone' in cmds_cats
     assert 'elderberry' in cmds_cats['Alone']
+    assert 'main' in cmds_cats['Alone']
+
+    # Test subcommand was autoloaded
+    result = command_sets_app.app_cmd('main sub')
+    assert 'Subcommand Ran' in result.stdout
 
     assert 'Also Alone' in cmds_cats
     assert 'durian' in cmds_cats['Also Alone']
@@ -150,6 +175,11 @@ def test_load_commands(command_sets_manual):
 
     assert 'Alone' in cmds_cats
     assert 'elderberry' in cmds_cats['Alone']
+    assert 'main' in cmds_cats['Alone']
+
+    # Test subcommand was loaded
+    result = command_sets_manual.app_cmd('main sub')
+    assert 'Subcommand Ran' in result.stdout
 
     assert 'Fruits' in cmds_cats
     assert 'cranberry' in cmds_cats['Fruits']
@@ -172,6 +202,11 @@ def test_load_commands(command_sets_manual):
 
     assert 'Alone' in cmds_cats
     assert 'elderberry' in cmds_cats['Alone']
+    assert 'main' in cmds_cats['Alone']
+
+    # Test subcommand was loaded
+    result = command_sets_manual.app_cmd('main sub')
+    assert 'Subcommand Ran' in result.stdout
 
     assert 'Fruits' in cmds_cats
     assert 'cranberry' in cmds_cats['Fruits']