Fix: capture TypeError caused by dynamic reloading on settings save a…

…nd load

Usage of super(MyClass, self) is henceforth discouraged due to dynamic reloading within OctoPrint's plugin subsystem. Refer to https://thingspython.wordpress.com/2010/09/27/another-super-wrinkle-raising-typeerror/ for details on this problem.

Action by plugin authors is needed to remove the super(...) call and substitute it with octoprint.plugin.SettingsPlugin.on_settings_save(self, data) and octoprint.plugin.SettingsPlugin.on_settings_load(self). Without these modifications, calls to plugin methods utilizing super(...) will fail after a call to the plugin managers reload_plugins method.

Closes #942

src/octoprint/plugin/types.py

@@ -718,7 +718,7 @@ def get_settings_defaults(self):
 	       def on_settings_save(self, data):
 	           old_flag = self._settings.get_boolean(["sub", "some_flag"])
 
-	           super(MySettingsPlugin, self).on_settings_save(data)
+	           octoprint.plugin.SettingsPlugin.on_settings_save(self, data)
 
 	           new_flag = self._settings.get_boolean(["sub", "some_flag"])
 	           if old_flag != new_flag:

src/octoprint/server/api/settings.py

@@ -26,6 +26,8 @@
 
 @api.route("/settings", methods=["GET"])
 def getSettings():
+	logger = logging.getLogger(__name__)
+
 	s = settings()
 
 	connectionOptions = get_connection_options()
@@ -118,17 +120,25 @@ def getSettings():
 		for name in gcode_scripts:
 			data["scripts"]["gcode"][name] = s.loadScript("gcode", name, source=True)
 
-	def process_plugin_result(name, plugin, result):
+	def process_plugin_result(name, result):
 		if result:
 			if not "plugins" in data:
 				data["plugins"] = dict()
 			if "__enabled" in result:
 				del result["__enabled"]
 			data["plugins"][name] = result
 
-	octoprint.plugin.call_plugin(octoprint.plugin.SettingsPlugin,
-	                             "on_settings_load",
-	                             callback=process_plugin_result)
+	for plugin in octoprint.plugin.plugin_manager().get_implementations(octoprint.plugin.SettingsPlugin):
+		try:
+			result = plugin.on_settings_load()
+			process_plugin_result(plugin._identifier, result)
+		except TypeError:
+			logger.warn("Could not load settings for plugin {name} ({version}) since it called super(...)".format(name=plugin._plugin_name, version=plugin._plugin_version))
+			logger.warn("in a way which has issues due to OctoPrint's dynamic reloading after plugin operations.")
+			logger.warn("Please contact the plugin's author and ask to update the plugin to use a direct call like")
+			logger.warn("octoprint.plugin.SettingsPlugin.on_settings_load(self) instead.")
+		except:
+			logger.exception("Could not load settings for plugin {name} ({version})".format(version=plugin._plugin_version, name=plugin._plugin_name))
 
 	return jsonify(data)
 
@@ -137,6 +147,8 @@ def process_plugin_result(name, plugin, result):
 @restricted_access
 @admin_permission.require(403)
 def setSettings():
+	logger = logging.getLogger(__name__)
+
 	if not "application/json" in request.headers["Content-Type"]:
 		return make_response("Expected content-type JSON", 400)
 
@@ -235,8 +247,15 @@ def setSettings():
 		for plugin in octoprint.plugin.plugin_manager().get_implementations(octoprint.plugin.SettingsPlugin):
 			plugin_id = plugin._identifier
 			if plugin_id in data["plugins"]:
-				plugin.on_settings_save(data["plugins"][plugin_id])
-
+				try:
+					plugin.on_settings_save(data["plugins"][plugin_id])
+				except TypeError:
+					logger.warn("Could not save settings for plugin {name} ({version}) since it called super(...)".format(name=plugin._plugin_name, version=plugin._plugin_version))
+					logger.warn("in a way which has issues due to OctoPrint's dynamic reloading after plugin operations.")
+					logger.warn("Please contact the plugin's author and ask to update the plugin to use a direct call like")
+					logger.warn("octoprint.plugin.SettingsPlugin.on_settings_save(self, data) instead.")
+				except:
+					logger.exception("Could not save settings for plugin {name} ({version})".format(version=plugin._plugin_version, name=plugin._plugin_name))
 
 	if s.save():
 		eventManager().fire(Events.SETTINGS_UPDATED)