The next version will be 0.9.0

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

diff --git a/tasklib/task.py b/tasklib/task.py
index 6392b9e96e7b39f1c569cdb22089d232c3ba2fae..56cda19900725263cd4bfd6d086dfd83ad8af644 100644 (file)
--- a/tasklib/task.py
+++ b/tasklib/task.py
@@ -4,8 +4,11 @@ import datetime
 import json
 import logging
 import os
 import json
 import logging
 import os

+import pytz

 import six
 import six

+import sys

 import subprocess
 import subprocess

+import tzlocal

 
 DATE_FORMAT = '%Y%m%dT%H%M%SZ'
 REPR_OUTPUT_SIZE = 10
 
 DATE_FORMAT = '%Y%m%dT%H%M%SZ'
 REPR_OUTPUT_SIZE = 10


@@ -18,16 +21,69 @@ VERSION_2_3_0 = six.u('2.3.0')
 VERSION_2_4_0 = six.u('2.4.0')
 
 logger = logging.getLogger(__name__)
 VERSION_2_4_0 = six.u('2.4.0')
 
 logger = logging.getLogger(__name__)

+local_zone = tzlocal.get_localzone()

 
 
 class TaskWarriorException(Exception):
     pass
 
 
 
 
 class TaskWarriorException(Exception):
     pass
 
 

+class ReadOnlyDictView(object):
+    """
+    Provides simplified read-only view upon dict object.
+    """
+
+    def __init__(self, viewed_dict):
+        self.viewed_dict = viewed_dict
+
+    def __getitem__(self, key):
+        return copy.deepcopy(self.viewed_dict.__getitem__(key))
+
+    def __contains__(self, k):
+        return self.viewed_dict.__contains__(k)
+
+    def __iter__(self):
+        for value in self.viewed_dict:
+            yield copy.deepcopy(value)
+
+    def __len__(self):
+        return len(self.viewed_dict)
+
+    def get(self, key, default=None):
+        return copy.deepcopy(self.viewed_dict.get(key, default))
+
+    def items(self):
+        return [copy.deepcopy(v) for v in self.viewed_dict.items()]
+
+    def values(self):
+        return [copy.deepcopy(v) for v in self.viewed_dict.values()]
+
+

 class SerializingObject(object):
     """
     Common ancestor for TaskResource & TaskFilter, since they both
     need to serialize arguments.
 class SerializingObject(object):
     """
     Common ancestor for TaskResource & TaskFilter, since they both
     need to serialize arguments.

+
+    Serializing method should hold the following contract:
+      - any empty value (meaning removal of the attribute)
+        is deserialized into a empty string
+      - None denotes a empty value for any attribute
+
+    Deserializing method should hold the following contract:
+      - None denotes a empty value for any attribute (however,
+        this is here as a safeguard, TaskWarrior currently does
+        not export empty-valued attributes) if the attribute
+        is not iterable (e.g. list or set), in which case
+        a empty iterable should be used.
+
+    Normalizing methods should hold the following contract:
+      - They are used to validate and normalize the user input.
+        Any attribute value that comes from the user (during Task
+        initialization, assignign values to Task attributes, or
+        filtering by user-provided values of attributes) is first
+        validated and normalized using the normalize_{key} method.
+      - If validation or normalization fails, normalizer is expected
+        to raise ValueError.

     """
 
     def _deserialize(self, key, value):
     """
 
     def _deserialize(self, key, value):


@@ -40,15 +96,40 @@ class SerializingObject(object):
                                  lambda x: x if x is not None else '')
         return dehydrate_func(value)
 
                                  lambda x: x if x is not None else '')
         return dehydrate_func(value)
 

+    def _normalize(self, key, value):
+        """
+        Use normalize_<key> methods to normalize user input. Any user
+        input will be normalized at the moment it is used as filter,
+        or entered as a value of Task attribute.
+        """
+
+        # None value should not be converted by normalizer
+        if value is None:
+            return None
+
+        normalize_func = getattr(self, 'normalize_{0}'.format(key),
+                                 lambda x: x)
+
+        return normalize_func(value)
+

     def timestamp_serializer(self, date):
         if not date:
     def timestamp_serializer(self, date):
         if not date:

-            return None
+            return ''
+
+        # Any serialized timestamp should be localized, we need to
+        # convert to UTC before converting to string (DATE_FORMAT uses UTC)
+        date = date.astimezone(pytz.utc)
+

         return date.strftime(DATE_FORMAT)
 
     def timestamp_deserializer(self, date_str):
         if not date_str:
             return None
         return date.strftime(DATE_FORMAT)
 
     def timestamp_deserializer(self, date_str):
         if not date_str:
             return None

-        return datetime.datetime.strptime(date_str, DATE_FORMAT)
+
+        # Return timestamp localized in the local zone
+        naive_timestamp = datetime.datetime.strptime(date_str, DATE_FORMAT)
+        localized_timestamp = pytz.utc.localize(naive_timestamp)
+        return localized_timestamp.astimezone(local_zone)

 
     def serialize_entry(self, value):
         return self.timestamp_serializer(value)
 
     def serialize_entry(self, value):
         return self.timestamp_serializer(value)


@@ -56,36 +137,81 @@ class SerializingObject(object):
     def deserialize_entry(self, value):
         return self.timestamp_deserializer(value)
 
     def deserialize_entry(self, value):
         return self.timestamp_deserializer(value)
 

+    def normalize_entry(self, value):
+        return self.datetime_normalizer(value)
+

     def serialize_modified(self, value):
         return self.timestamp_serializer(value)
 
     def deserialize_modified(self, value):
         return self.timestamp_deserializer(value)
 
     def serialize_modified(self, value):
         return self.timestamp_serializer(value)
 
     def deserialize_modified(self, value):
         return self.timestamp_deserializer(value)
 

+    def normalize_modified(self, value):
+        return self.datetime_normalizer(value)
+
+    def serialize_start(self, value):
+        return self.timestamp_serializer(value)
+
+    def deserialize_start(self, value):
+        return self.timestamp_deserializer(value)
+
+    def normalize_start(self, value):
+        return self.datetime_normalizer(value)
+
+    def serialize_end(self, value):
+        return self.timestamp_serializer(value)
+
+    def deserialize_end(self, value):
+        return self.timestamp_deserializer(value)
+
+    def normalize_end(self, value):
+        return self.datetime_normalizer(value)
+

     def serialize_due(self, value):
         return self.timestamp_serializer(value)
 
     def deserialize_due(self, value):
         return self.timestamp_deserializer(value)
 
     def serialize_due(self, value):
         return self.timestamp_serializer(value)
 
     def deserialize_due(self, value):
         return self.timestamp_deserializer(value)
 

+    def normalize_due(self, value):
+        return self.datetime_normalizer(value)
+

     def serialize_scheduled(self, value):
         return self.timestamp_serializer(value)
 
     def deserialize_scheduled(self, value):
         return self.timestamp_deserializer(value)
 
     def serialize_scheduled(self, value):
         return self.timestamp_serializer(value)
 
     def deserialize_scheduled(self, value):
         return self.timestamp_deserializer(value)
 

+    def normalize_scheduled(self, value):
+        return self.datetime_normalizer(value)
+

     def serialize_until(self, value):
         return self.timestamp_serializer(value)
 
     def deserialize_until(self, value):
         return self.timestamp_deserializer(value)
 
     def serialize_until(self, value):
         return self.timestamp_serializer(value)
 
     def deserialize_until(self, value):
         return self.timestamp_deserializer(value)
 

+    def normalize_until(self, value):
+        return self.datetime_normalizer(value)
+

     def serialize_wait(self, value):
         return self.timestamp_serializer(value)
 
     def deserialize_wait(self, value):
         return self.timestamp_deserializer(value)
 
     def serialize_wait(self, value):
         return self.timestamp_serializer(value)
 
     def deserialize_wait(self, value):
         return self.timestamp_deserializer(value)
 

+    def normalize_wait(self, value):
+        return self.datetime_normalizer(value)
+
+    def serialize_annotations(self, value):
+        value = value if value is not None else []
+
+        # This may seem weird, but it's correct, we want to export
+        # a list of dicts as serialized value
+        serialized_annotations = [json.loads(annotation.export_data())
+                                  for annotation in value]
+        return serialized_annotations if serialized_annotations else ''
+

     def deserialize_annotations(self, data):
         return [TaskAnnotation(self, d) for d in data] if data else []
 
     def deserialize_annotations(self, data):
         return [TaskAnnotation(self, d) for d in data] if data else []
 


@@ -93,29 +219,63 @@ class SerializingObject(object):
         return ','.join(tags) if tags else ''
 
     def deserialize_tags(self, tags):
         return ','.join(tags) if tags else ''
 
     def deserialize_tags(self, tags):

-        if isinstance(tags, basestring):
+        if isinstance(tags, six.string_types):

             return tags.split(',') if tags else []
             return tags.split(',') if tags else []

-        return tags
+        return tags or []

 
 

-    def serialize_depends(self, cur_dependencies):
+    def serialize_depends(self, value):

         # Return the list of uuids
         # Return the list of uuids

-        return ','.join(task['uuid'] for task in cur_dependencies)
+        value = value if value is not None else set()
+        return ','.join(task['uuid'] for task in value)

 
     def deserialize_depends(self, raw_uuids):
         raw_uuids = raw_uuids or ''  # Convert None to empty string
         uuids = raw_uuids.split(',')
         return set(self.warrior.tasks.get(uuid=uuid) for uuid in uuids if uuid)
 
 
     def deserialize_depends(self, raw_uuids):
         raw_uuids = raw_uuids or ''  # Convert None to empty string
         uuids = raw_uuids.split(',')
         return set(self.warrior.tasks.get(uuid=uuid) for uuid in uuids if uuid)
 

+    def datetime_normalizer(self, value):
+        """
+        Normalizes date/datetime value (considered to come from user input)
+        to localized datetime value. Following conversions happen:
+
+        naive date -> localized datetime with the same date, and time=midnight
+        naive datetime -> localized datetime with the same value
+        localized datetime -> localized datetime (no conversion)
+        """
+
+        if (isinstance(value, datetime.date)
+            and not isinstance(value, datetime.datetime)):
+            # Convert to local midnight
+            value_full = datetime.datetime.combine(value, datetime.time.min)
+            localized = local_zone.localize(value_full)
+        elif isinstance(value, datetime.datetime) and value.tzinfo is None:
+            # Convert to localized datetime object
+            localized = local_zone.localize(value)
+        else:
+            # If the value is already localized, there is no need to change
+            # time zone at this point. Also None is a valid value too.
+            localized = value
+
+        return localized
+
+    def normalize_uuid(self, value):
+        # Enforce sane UUID
+        if not isinstance(value, six.string_types) or value == '':
+            raise ValueError("UUID must be a valid non-empty string, "
+                             "not: {}".format(value))
+
+        return value
+

 
 class TaskResource(SerializingObject):
     read_only_fields = []
 
     def _load_data(self, data):
 
 class TaskResource(SerializingObject):
     read_only_fields = []
 
     def _load_data(self, data):

-        self._data = data
+        self._data = dict((key, self._deserialize(key, value))
+                          for key, value in data.items())

         # We need to use a copy for original data, so that changes
         # We need to use a copy for original data, so that changes

-        # are not propagated. Shallow copy is alright, since data dict uses only
-        # primitive data types
-        self._original_data = data.copy()
+        # are not propagated.
+        self._original_data = copy.deepcopy(self._data)

 
     def _update_data(self, data, update_original=False):
         """
 
     def _update_data(self, data, update_original=False):
         """


@@ -123,11 +283,12 @@ class TaskResource(SerializingObject):
         updates should already be serialized. If update_original is True, the
         original_data dict is updated as well.
         """
         updates should already be serialized. If update_original is True, the
         original_data dict is updated as well.
         """

-
-        self._data.update(data)
+        self._data.update(dict((key, self._deserialize(key, value))
+                               for key, value in data.items()))

 
         if update_original:
 
         if update_original:

-            self._original_data.update(data)
+            self._original_data = copy.deepcopy(self._data)
+

 
     def __getitem__(self, key):
         # This is a workaround to make TaskResource non-iterable
 
     def __getitem__(self, key):
         # This is a workaround to make TaskResource non-iterable


@@ -138,12 +299,18 @@ class TaskResource(SerializingObject):
         except ValueError:
             pass
 
         except ValueError:
             pass
 

-        return self._deserialize(key, self._data.get(key))
+        if key not in self._data:
+            self._data[key] = self._deserialize(key, None)
+
+        return self._data.get(key)

 
     def __setitem__(self, key, value):
         if key in self.read_only_fields:
             raise RuntimeError('Field \'%s\' is read-only' % key)
 
     def __setitem__(self, key, value):
         if key in self.read_only_fields:
             raise RuntimeError('Field \'%s\' is read-only' % key)

-        self._data[key] = self._serialize(key, value)
+
+        # Normalize the user input before saving it
+        value = self._normalize(key, value)
+        self._data[key] = value

 
     def __str__(self):
         s = six.text_type(self.__unicode__())
 
     def __str__(self):
         s = six.text_type(self.__unicode__())


@@ -154,6 +321,40 @@ class TaskResource(SerializingObject):
     def __repr__(self):
         return str(self)
 
     def __repr__(self):
         return str(self)
 

+    def export_data(self):
+        """
+        Exports current data contained in the Task as JSON
+        """
+
+        # We need to remove spaces for TW-1504, use custom separators
+        data_tuples = ((key, self._serialize(key, value))
+                       for key, value in six.iteritems(self._data))
+
+        # Empty string denotes empty serialized value, we do not want
+        # to pass that to TaskWarrior.
+        data_tuples = filter(lambda t: t[1] is not '', data_tuples)
+        data = dict(data_tuples)
+        return json.dumps(data, separators=(',',':'))
+
+    @property
+    def _modified_fields(self):
+        writable_fields = set(self._data.keys()) - set(self.read_only_fields)
+        for key in writable_fields:
+            new_value = self._data.get(key)
+            old_value = self._original_data.get(key)
+
+            # Make sure not to mark data removal as modified field if the
+            # field originally had some empty value
+            if key in self._data and not new_value and not old_value:
+                continue
+
+            if new_value != old_value:
+                yield key
+
+    @property
+    def modified(self):
+        return bool(list(self._modified_fields))
+

 
 class TaskAnnotation(TaskResource):
     read_only_fields = ['entry', 'description']
 
 class TaskAnnotation(TaskResource):
     read_only_fields = ['entry', 'description']


@@ -168,6 +369,11 @@ class TaskAnnotation(TaskResource):
     def __unicode__(self):
         return self['description']
 
     def __unicode__(self):
         return self['description']
 

+    def __eq__(self, other):
+        # consider 2 annotations equal if they belong to the same task, and
+        # their data dics are the same
+        return self.task == other.task and self._data == other._data
+

     __repr__ = __unicode__
 
 
     __repr__ = __unicode__
 
 


@@ -196,6 +402,45 @@ class Task(TaskResource):
         """
         pass
 
         """
         pass
 

+    @classmethod
+    def from_input(cls, input_file=sys.stdin, modify=None, warrior=None):
+        """
+        Creates a Task object, directly from the stdin, by reading one line.
+        If modify=True, two lines are used, first line interpreted as the
+        original state of the Task object, and second line as its new,
+        modified value. This is consistent with the TaskWarrior's hook
+        system.
+
+        Object created by this method should not be saved, deleted
+        or refreshed, as t could create a infinite loop. For this
+        reason, TaskWarrior instance is set to None.
+
+        Input_file argument can be used to specify the input file,
+        but defaults to sys.stdin.
+        """
+
+        # Detect the hook type if not given directly
+        name = os.path.basename(sys.argv[0])
+        modify = name.startswith('on-modify') if modify is None else modify
+
+        # Create the TaskWarrior instance if none passed
+        if warrior is None:
+            hook_parent_dir = os.path.dirname(os.path.dirname(sys.argv[0]))
+            warrior = TaskWarrior(data_location=hook_parent_dir)
+
+        # TaskWarrior instance is set to None
+        task = cls(warrior)
+
+        # Load the data from the input
+        task._load_data(json.loads(input_file.readline().strip()))
+
+        # If this is a on-modify event, we are provided with additional
+        # line of input, which provides updated data
+        if modify:
+            task._update_data(json.loads(input_file.readline().strip()))
+
+        return task
+

     def __init__(self, warrior, **kwargs):
         self.warrior = warrior
 
     def __init__(self, warrior, **kwargs):
         self.warrior = warrior
 


@@ -209,8 +454,12 @@ class Task(TaskResource):
         # __init__ methods, that would be confusing
 
         # Rather unfortunate syntax due to python2.6 comaptiblity
         # __init__ methods, that would be confusing
 
         # Rather unfortunate syntax due to python2.6 comaptiblity

-        self._load_data(dict((key, self._serialize(key, value))
-                        for (key, value) in six.iteritems(kwargs)))
+        self._data = dict((key, self._normalize(key, value))
+                          for (key, value) in six.iteritems(kwargs))
+        self._original_data = copy.deepcopy(self._data)
+
+        # Provide read only access to the original data
+        self.original = ReadOnlyDictView(self._original_data)

 
     def __unicode__(self):
         return self['description']
 
     def __unicode__(self):
         return self['description']


@@ -232,13 +481,6 @@ class Task(TaskResource):
             # If the tasks are not saved, return hash of instance id
             return id(self).__hash__()
 
             # If the tasks are not saved, return hash of instance id
             return id(self).__hash__()
 

-    @property
-    def _modified_fields(self):
-        writable_fields = set(self._data.keys()) - set(self.read_only_fields)
-        for key in writable_fields:
-            if self._data.get(key) != self._original_data.get(key):
-                yield key
-

     @property
     def completed(self):
         return self['status'] == six.text_type('completed')
     @property
     def completed(self):
         return self['status'] == six.text_type('completed')


@@ -261,7 +503,7 @@ class Task(TaskResource):
 
     def serialize_depends(self, cur_dependencies):
         # Check that all the tasks are saved
 
     def serialize_depends(self, cur_dependencies):
         # Check that all the tasks are saved

-        for task in cur_dependencies:
+        for task in (cur_dependencies or set()):

             if not task.saved:
                 raise Task.NotSaved('Task \'%s\' needs to be saved before '
                                     'it can be set as dependency.' % task)
             if not task.saved:
                 raise Task.NotSaved('Task \'%s\' needs to be saved before '
                                     'it can be set as dependency.' % task)


@@ -276,8 +518,7 @@ class Task(TaskResource):
         # to keep a list of all depedencies in the _data dictionary,
         # not just currently added/removed ones
 
         # to keep a list of all depedencies in the _data dictionary,
         # not just currently added/removed ones
 

-        old_dependencies_raw = self._original_data.get('depends','')
-        old_dependencies = self.deserialize_depends(old_dependencies_raw)
+        old_dependencies = self._original_data.get('depends', set())

 
         added = self['depends'] - old_dependencies
         removed = old_dependencies - self['depends']
 
         added = self['depends'] - old_dependencies
         removed = old_dependencies - self['depends']


@@ -309,8 +550,24 @@ class Task(TaskResource):
         self.warrior.execute_command([self['uuid'], 'delete'])
 
         # Refresh the status again, so that we have updated info stored
         self.warrior.execute_command([self['uuid'], 'delete'])
 
         # Refresh the status again, so that we have updated info stored

+        self.refresh(only_fields=['status', 'start', 'end'])
+
+    def start(self):
+        if not self.saved:
+            raise Task.NotSaved("Task needs to be saved before it can be started")
+
+        # Refresh, and raise exception if task is already completed/deleted

         self.refresh(only_fields=['status'])
 
         self.refresh(only_fields=['status'])
 

+        if self.completed:
+            raise Task.CompletedTask("Cannot start a completed task")
+        elif self.deleted:
+            raise Task.DeletedTask("Deleted task cannot be started")
+
+        self.warrior.execute_command([self['uuid'], 'start'])
+
+        # Refresh the status again, so that we have updated info stored
+        self.refresh(only_fields=['status', 'start'])

 
     def done(self):
         if not self.saved:
 
     def done(self):
         if not self.saved:


@@ -327,9 +584,12 @@ class Task(TaskResource):
         self.warrior.execute_command([self['uuid'], 'done'])
 
         # Refresh the status again, so that we have updated info stored
         self.warrior.execute_command([self['uuid'], 'done'])
 
         # Refresh the status again, so that we have updated info stored

-        self.refresh(only_fields=['status'])
+        self.refresh(only_fields=['status', 'start', 'end'])

 
     def save(self):
 
     def save(self):

+        if self.saved and not self.modified:
+            return
+

         args = [self['uuid'], 'modify'] if self.saved else ['add']
         args.extend(self._get_modified_fields_as_args())
         output = self.warrior.execute_command(args)
         args = [self['uuid'], 'modify'] if self.saved else ['add']
         args.extend(self._get_modified_fields_as_args())
         output = self.warrior.execute_command(args)


@@ -347,6 +607,9 @@ class Task(TaskResource):
             # Circumvent the ID storage, since ID is considered read-only
             self._data['id'] = int(id_lines[0].split(' ')[2].rstrip('.'))
 
             # Circumvent the ID storage, since ID is considered read-only
             self._data['id'] = int(id_lines[0].split(' ')[2].rstrip('.'))
 

+        # Refreshing is very important here, as not only modification time
+        # is updated, but arbitrary attribute may have changed due hooks
+        # altering the data before saving

         self.refresh()
 
     def add_annotation(self, annotation):
         self.refresh()
 
     def add_annotation(self, annotation):


@@ -373,9 +636,21 @@ class Task(TaskResource):
         def add_field(field):
             # Add the output of format_field method to args list (defaults to
             # field:value)
         def add_field(field):
             # Add the output of format_field method to args list (defaults to
             # field:value)

-            format_default = lambda k: "{0}:'{1}'".format(k, self._data[k] or '')
+            serialized_value = self._serialize(field, self._data[field])
+
+            # Empty values should not be enclosed in quotation marks, see
+            # TW-1510
+            if serialized_value is '':
+                escaped_serialized_value = ''
+            else:
+                escaped_serialized_value = "'{0}'".format(serialized_value)
+
+            format_default = lambda: "{0}:{1}".format(field,
+                                                      escaped_serialized_value)
+

             format_func = getattr(self, 'format_{0}'.format(field),
             format_func = getattr(self, 'format_{0}'.format(field),

-                                  lambda: format_default(field))
+                                  format_default)
+

             args.append(format_func())
 
         # If we're modifying saved task, simply pass on all modified fields
             args.append(format_func())
 
         # If we're modifying saved task, simply pass on all modified fields


@@ -408,7 +683,6 @@ class Task(TaskResource):
         else:
             self._load_data(new_data)
 
         else:
             self._load_data(new_data)
 

-

 class TaskFilter(SerializingObject):
     """
     A set of parameters to filter the task list with.
 class TaskFilter(SerializingObject):
     """
     A set of parameters to filter the task list with.


@@ -426,6 +700,9 @@ class TaskFilter(SerializingObject):
         # Replace the value with empty string, since that is the
         # convention in TW for empty values
         attribute_key = key.split('.')[0]
         # Replace the value with empty string, since that is the
         # convention in TW for empty values
         attribute_key = key.split('.')[0]

+
+        # Since this is user input, we need to normalize before we serialize
+        value = self._normalize(key, value)

         value = self._serialize(attribute_key, value)
 
         # If we are filtering by uuid:, do not use uuid keyword
         value = self._serialize(attribute_key, value)
 
         # If we are filtering by uuid:, do not use uuid keyword


@@ -570,7 +847,8 @@ class TaskWarrior(object):
         self.config = {
             'data.location': os.path.expanduser(data_location),
             'confirmation': 'no',
         self.config = {
             'data.location': os.path.expanduser(data_location),
             'confirmation': 'no',

-            'dependency.confirmation': 'no', # See TW-1483 or taskrc man page
+            'dependency.confirmation': 'no',  # See TW-1483 or taskrc man page
+            'recurrence.confirmation': 'no',  # Necessary for modifying R tasks

         }
         self.tasks = TaskQuerySet(self)
         self.version = self._get_version()
         }
         self.tasks = TaskQuerySet(self)
         self.version = self._get_version()


@@ -592,22 +870,30 @@ class TaskWarrior(object):
         stdout, stderr = [x.decode('utf-8') for x in p.communicate()]
         return stdout.strip('\n')
 
         stdout, stderr = [x.decode('utf-8') for x in p.communicate()]
         return stdout.strip('\n')
 

-    def execute_command(self, args, config_override={}):
+    def execute_command(self, args, config_override={}, allow_failure=True):

         command_args = self._get_command_args(
             args, config_override=config_override)
         logger.debug(' '.join(command_args))
         p = subprocess.Popen(command_args, stdout=subprocess.PIPE,
                              stderr=subprocess.PIPE)
         stdout, stderr = [x.decode('utf-8') for x in p.communicate()]
         command_args = self._get_command_args(
             args, config_override=config_override)
         logger.debug(' '.join(command_args))
         p = subprocess.Popen(command_args, stdout=subprocess.PIPE,
                              stderr=subprocess.PIPE)
         stdout, stderr = [x.decode('utf-8') for x in p.communicate()]

-        if p.returncode:
+        if p.returncode and allow_failure:

             if stderr.strip():
             if stderr.strip():

-                error_msg = stderr.strip().splitlines()[-1]
+                error_msg = stderr.strip()

             else:
                 error_msg = stdout.strip()
             raise TaskWarriorException(error_msg)
         return stdout.strip().split('\n')
 
             else:
                 error_msg = stdout.strip()
             raise TaskWarriorException(error_msg)
         return stdout.strip().split('\n')
 

+    def enforce_recurrence(self):
+        # Run arbitrary report command which will trigger generation
+        # of recurrent tasks.
+        # TODO: Make a version dependant enforcement once
+        #       TW-1531 is handled
+        self.execute_command(['next'], allow_failure=False)
+

     def filter_tasks(self, filter_obj):
     def filter_tasks(self, filter_obj):

+        self.enforce_recurrence()

         args = ['export', '--'] + filter_obj.get_filter_params()
         tasks = []
         for line in self.execute_command(args):
         args = ['export', '--'] + filter_obj.get_filter_params()
         tasks = []
         for line in self.execute_command(args):