Merge pull request #15074 from ansible/pluginloader-cleanups

Cleanup some minor issues in PuginLoader:

lib/ansible/plugins/__init__.py

@@ -316,6 +316,7 @@ class PluginLoader:
     def get(self, name, *args, **kwargs):
         ''' instantiates a plugin of the given name using arguments '''
 
+        class_only = kwargs.pop('class_only', False)
         if name in self.aliases:
             name = self.aliases[name]
         path = self.find_plugin(name)
@@ -325,23 +326,28 @@ class PluginLoader:
         if path not in self._module_cache:
             self._module_cache[path] = self._load_module_source('.'.join([self.package, name]), path)
 
-        if kwargs.get('class_only', False):
-            obj = getattr(self._module_cache[path], self.class_name)
-        else:
-            obj = getattr(self._module_cache[path], self.class_name)(*args, **kwargs)
-            if self.base_class:
-                # The import path is hardcoded and should be the right place,
-                # so we are not expecting an ImportError.
-                module = __import__(self.package, fromlist=[self.base_class])
-                # Check whether this obj has the required base class.
-                if not issubclass(obj.__class__, getattr(module, self.base_class, None)):
-                    return None
+        obj = getattr(self._module_cache[path], self.class_name)
+        if self.base_class:
+            # The import path is hardcoded and should be the right place,
+            # so we are not expecting an ImportError.
+            module = __import__(self.package, fromlist=[self.base_class])
+            # Check whether this obj has the required base class.
+            try:
+                plugin_class = getattr(module, self.base_class)
+            except AttributeError:
+                return None
+            if not issubclass(obj, plugin_class):
+                return None
+
+        if not class_only:
+            obj = obj(*args, **kwargs)
 
         return obj
 
     def all(self, *args, **kwargs):
         ''' instantiates all plugins with the same arguments '''
 
+        class_only = kwargs.pop('class_only', False)
         for i in self._get_paths():
             matches = glob.glob(os.path.join(i, "*.py"))
             matches.sort()
@@ -353,14 +359,22 @@ class PluginLoader:
                 if path not in self._module_cache:
                     self._module_cache[path] = self._load_module_source(name, path)
 
-                if kwargs.get('class_only', False):
-                    obj = getattr(self._module_cache[path], self.class_name)
-                else:
-                    obj = getattr(self._module_cache[path], self.class_name)(*args, **kwargs)
-
-                    if self.base_class and self.base_class not in [base.__name__ for base in obj.__class__.__bases__]:
+                obj = getattr(self._module_cache[path], self.class_name)
+                if self.base_class:
+                    # The import path is hardcoded and should be the right place,
+                    # so we are not expecting an ImportError.
+                    module = __import__(self.package, fromlist=[self.base_class])
+                    # Check whether this obj has the required base class.
+                    try:
+                        plugin_class = getattr(module, self.base_class)
+                    except AttributeError:
+                        continue
+                    if not issubclass(obj, plugin_class):
                         continue
 
+                if not class_only:
+                    obj = obj(*args, **kwargs)
+
                 # set extra info on the module, in case we want it later
                 setattr(obj, '_original_path', path)
                 yield obj