backends: Introduce a Backend base class

[etc/taskwarrior.git] / tasklib / task.py

diff --git a/tasklib/task.py b/tasklib/task.py
index ed89653eab7e593a396bcaa6720cc2266e859599..8374eb79998980b2af4a997db17cc026ac4bb229 100644 (file)
--- a/tasklib/task.py
+++ b/tasklib/task.py
@@ -24,6 +24,8 @@ VERSION_2_4_0 = six.u('2.4.0')
 VERSION_2_4_1 = six.u('2.4.1')
 VERSION_2_4_2 = six.u('2.4.2')
 VERSION_2_4_3 = six.u('2.4.3')
+VERSION_2_4_4 = six.u('2.4.4')
+VERSION_2_4_5 = six.u('2.4.5')
 
 logger = logging.getLogger(__name__)
 local_zone = tzlocal.get_localzone()
@@ -392,9 +394,9 @@ class TaskResource(SerializingObject):
 class TaskAnnotation(TaskResource):
     read_only_fields = ['entry', 'description']
 
-    def __init__(self, task, data={}):
+    def __init__(self, task, data=None):
         self.task = task
-        self._load_data(data)
+        self._load_data(data or dict())
         super(TaskAnnotation, self).__init__(task.warrior)
 
     def remove(self):
@@ -744,7 +746,7 @@ class Task(TaskResource):
 
         return args
 
-    def refresh(self, only_fields=[], after_save=False):
+    def refresh(self, only_fields=None, after_save=False):
         # Raise error when trying to refresh a task that has not been saved
         if not self.saved:
             raise Task.NotSaved("Task needs to be saved to be refreshed")
@@ -761,7 +763,7 @@ class Task(TaskResource):
         # For older TW versions attempt to uniquely locate the task
         # using the data we have if it has been just saved.
         # This can happen when adding a completed task on older TW versions.
-        if (not valid(output) and self.warrior.version < six.text_type(u'2.4.5')
+        if (not valid(output) and self.warrior.version < VERSION_2_4_5
                 and after_save):
 
             # Make a copy, removing ID and UUID. It's most likely invalid
@@ -798,8 +800,8 @@ class TaskFilter(SerializingObject):
     A set of parameters to filter the task list with.
     """
 
-    def __init__(self, warrior, filter_params=[]):
-        self.filter_params = filter_params
+    def __init__(self, warrior, filter_params=None):
+        self.filter_params = filter_params or []
         super(TaskFilter, self).__init__(warrior)
 
     def add_filter(self, filter_str):
@@ -826,8 +828,10 @@ class TaskFilter(SerializingObject):
 
             # We enforce equality match by using 'is' (or 'none') modifier
             # Without using this syntax, filter fails due to TW-1479
-            modifier = '.is' if value else '.none'
-            key = key + modifier if '.' not in key else key
+            # which is, however, fixed in 2.4.5
+            if self.warrior.version < VERSION_2_4_5:
+                modifier = '.is' if value else '.none'
+                key = key + modifier if '.' not in key else key
 
             self.filter_params.append(six.u("{0}:{1}").format(key, value))
 
@@ -982,10 +986,10 @@ class TaskWarrior(object):
 
         self.tasks = TaskQuerySet(self)
 
-    def _get_command_args(self, args, config_override={}):
+    def _get_command_args(self, args, config_override=None):
         command_args = ['task', 'rc:{0}'.format(self.taskrc_location)]
         config = self.config.copy()
-        config.update(config_override)
+        config.update(config_override or dict())
         for item in config.items():
             command_args.append('rc.{0}={1}'.format(*item))
         command_args.extend(map(six.text_type, args))
@@ -1015,7 +1019,7 @@ class TaskWarrior(object):
 
         return config
 
-    def execute_command(self, args, config_override={}, allow_failure=True,
+    def execute_command(self, args, config_override=None, allow_failure=True,
                         return_all=False):
         command_args = self._get_command_args(
             args, config_override=config_override)