refactor(commands): direct help call only when the method also accepts the message

Space bunny on d60e7cf1: operators may install their own command files inside modules/commands or modules/commands/alternatives (documented, and preserved across upgrades), so a class under modules. is not necessarily bundled. Such a command written as get_help_text(self) was treated as bundled, called with the message and raised, so help returned nothing where dev returned its text. help_text_for now calls once with the message only when the method comes from a class under modules. and its signature binds the message; otherwise, including when the signature can't be read, it uses dev's call-then-retry. New test: an operator command in the modules.commands namespace with get_help_text(self) gets its help.

modules/commands/base_command.py

@@ -4,6 +4,7 @@ Base command class for all MeshCore Bot commands
 Provides common functionality and interface for command implementations
 """
 
+import inspect
 import re
 from abc import ABC, abstractmethod
 from collections.abc import Callable, Iterator
@@ -71,17 +72,28 @@ def _defined_by_bundled_class(command: Any, method: Any) -> bool:
     return False
 
 
+def _accepts_message(method: Any, message: Any) -> bool:
+    """Whether ``method(message)`` binds, per its signature (False when that can't be read)."""
+    try:
+        inspect.signature(method).bind(message)
+    except (TypeError, ValueError):
+        return False
+    return True
+
+
 def help_text_for(command: Any, message: Any) -> str:
     """``command.get_help_text(message)``, retrying without the message for local plugins.
 
     Every bundled command's get_help_text takes the message, so when the
-    method comes from a bundled class it is called once and an error from its
+    method comes from a class under ``modules.`` and its signature accepts the
-    body propagates. Anything else (a local plugin or subclass override, which
+    message, it is called once and an error from its body propagates. Anything
-    may implement ``get_help_text(self)``, or any other callable) keeps the old
+    else keeps the old contract, where a TypeError from the message call is
-    contract: a TypeError from the message call is retried without the message.
+    retried without the message: local plugins and overrides, operator-installed
+    commands inside modules/commands written as ``get_help_text(self)``, and
+    any other callable.
     """
     get_help_text = command.get_help_text
-    if _defined_by_bundled_class(command, get_help_text):
+    if _defined_by_bundled_class(command, get_help_text) and _accepts_message(get_help_text, message):
         return get_help_text(message)
     try:
         return get_help_text(message)

tests/test_help_command.py

@@ -252,6 +252,25 @@ class TestGetSpecificHelp:
         cmd = HelpCommand(bot)
         cmd.get_specific_help("ping", Mock())  # must not raise
 
+    def test_operator_command_inside_modules_without_message_param_gets_help(self):
+        """An installed-only command file in modules/commands may use get_help_text(self)."""
+        from modules.commands.base_command import BaseCommand
+
+        class OperatorWeatherCommand(BaseCommand):
+            name = "operatorweather"
+
+            def get_help_text(self):
+                return "operator help"
+
+            async def execute(self, message):
+                return True
+
+        OperatorWeatherCommand.__module__ = "modules.commands.operatorweather"
+        bot = _make_bot()
+        bot.command_manager.commands = {"operatorweather": object.__new__(OperatorWeatherCommand)}
+        cmd = HelpCommand(bot)
+        cmd.get_specific_help("operatorweather", Mock())  # must not raise
+
     def test_local_plugin_help_keeps_the_typeerror_retry(self):
         """A local get_help_text(message=None) that raises TypeError is retried without it."""
         bot = _make_bot()