reload: Recurse into packaged modules

Force-reload all sub-modules of packages recursively.

See sopel-irc#1056.

sopel/modules/reload.py

@@ -16,6 +16,14 @@
 import sopel.module
 import subprocess
 
+try:
+    from importlib import reload
+except ImportError:
+    try:
+        from imp import reload
+    except ImportError:
+        pass  # fallback to builtin if neither module is available
+
 
 @sopel.module.nickname_commands("reload")
 @sopel.module.priority("low")
@@ -37,14 +45,38 @@ def f_reload(bot, trigger):
         bot.setup()
         return bot.reply('done')
 
-    if name not in sys.modules:
+    if (name not in sys.modules and name not in sopel.loader.enumerate_modules(bot.config)):
         return bot.reply('"%s" not loaded, try the `load` command' % name)
 
+    reload_module_tree(bot, name)
+
+
+def reload_module_tree(bot, name, seen=None):
+    from types import ModuleType
+
     old_module = sys.modules[name]
 
+    if seen is None:
+        seen = {}
+    if name not in seen:
+        seen[name] = []
+
     old_callables = {}
     for obj_name, obj in iteritems(vars(old_module)):
-        bot.unregister(obj)
+        if callable(obj):
+            bot.unregister(obj)
+        elif (type(obj) is ModuleType and
+              obj.__name__.startswith(name + '.') and
+              obj.__name__ not in sys.builtin_module_names):
+            # recurse into submodules, see issue 1056
+            if obj not in seen[name]:
+                seen[name].append(obj)
+                reload(obj)
+                reload_module_tree(bot, obj.__name__, seen)
+
+    modules = sopel.loader.enumerate_modules(bot.config)
+    if name not in modules:
+        return  # Only reload the top-level module, once recursion is finished
 
     # Also remove all references to sopel callables from top level of the
     # module, so that they will not get loaded again if reloading the
@@ -53,12 +85,10 @@ def f_reload(bot, trigger):
         delattr(old_module, obj_name)
 
     # Also delete the setup function
+    # Sub-modules shouldn't have setup functions, so do after the recursion check
     if hasattr(old_module, "setup"):
         delattr(old_module, "setup")
 
-    modules = sopel.loader.enumerate_modules(bot.config)
-    if name not in modules:
-        return bot.reply('"%s" not loaded, try the `load` command' % name)
     path, type_ = modules[name]
     load_module(bot, name, path, type_)