TaskWarrior: Return ReadOnlyDictView of config instead of passing a copy of a mutable...

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

diff --git a/tasklib/backends.py b/tasklib/backends.py
index 32a8018acb142ddb1257e0fe3916089bde2ecf70..fa5ce866a97f8d3f00964ac817aa68f9e1613e9f 100644 (file)
--- a/tasklib/backends.py
+++ b/tasklib/backends.py
@@ -9,7 +9,7 @@ import six
 import subprocess
 import copy
 
-from .task import Task, TaskQuerySet
+from .task import Task, TaskQuerySet, ReadOnlyDictView
 from .filters import TaskWarriorFilter
 from .serializing import local_zone
 
@@ -103,8 +103,9 @@ class TaskWarrior(Backend):
         if not os.path.exists(self.taskrc_location):
             self.taskrc_location = '/'
 
+        self._config = None
         self.version = self._get_version()
-        self.config = {
+        self.overrides = {
             'confirmation': 'no',
             'dependency.confirmation': 'no',  # See TW-1483 or taskrc man page
             'recurrence.confirmation': 'no',  # Necessary for modifying R tasks
@@ -122,15 +123,15 @@ class TaskWarrior(Backend):
             data_location = os.path.expanduser(data_location)
             if create and not os.path.exists(data_location):
                 os.makedirs(data_location)
-            self.config['data.location'] = data_location
+            self.overrides['data.location'] = data_location
 
         self.tasks = TaskQuerySet(self)
 
     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 or dict())
-        for item in config.items():
+        overrides = self.overrides.copy()
+        overrides.update(config_override or dict())
+        for item in overrides.items():
             command_args.append('rc.{0}={1}'.format(*item))
         command_args.extend(map(six.text_type, args))
         return command_args
@@ -229,7 +230,13 @@ class TaskWarrior(Backend):
 
     # Public interface
 
-    def get_config(self):
+    @property
+    def config(self):
+        # First, check if memoized information is available
+        if self._config:
+            return self._config
+
+        # If not, fetch the config using the 'show' command
         raw_output = self.execute_command(
             ['show'],
             config_override={'verbose': 'nothing'}
@@ -243,7 +250,10 @@ class TaskWarrior(Backend):
             if match:
                 config[match.group('key')] = match.group('value').strip()
 
-        return config
+        # Memoize the config dict
+        self._config = ReadOnlyDictView(config)
+
+        return self._config
 
     def execute_command(self, args, config_override=None, allow_failure=True,
                         return_all=False):