Fix for relative dates not always being calculated properly.

Fell into the trap of calling a function as a default parameter. Because
of this, relative dates used with the 'add' or 'do' command (recurrence)
were based on an offset when topydo was started, not when the subcommand
was executed. Usually these two events occur in the same second and this
bug was unnoticed for a long time. But now with prompt mode, this bug
may surface if you leave running topydo for longer than a day.

topydo/lib/Recurrence.py

@@ -58,10 +58,11 @@ def _advance_recurring_todo_helper(p_todo, p_offset):
 
     return todo
 
-def advance_recurring_todo(p_todo, p_offset=date.today()):
+def advance_recurring_todo(p_todo, p_offset=None):
+    p_offset = p_offset or date.today()
     return _advance_recurring_todo_helper(p_todo, p_offset)
 
-def strict_advance_recurring_todo(p_todo, p_offset=date.today()):
+def strict_advance_recurring_todo(p_todo, p_offset=None):
     """
     Given a Todo item, return a new instance of a Todo item with the dates
     shifted according to the recurrence rule.
@@ -74,5 +75,5 @@ def strict_advance_recurring_todo(p_todo, p_offset=date.today()):
 
     When no recurrence tag is present, an exception is raised.
     """
-    offset = p_todo.due_date() or p_offset
+    offset = p_todo.due_date() or p_offset or date.today()
     return _advance_recurring_todo_helper(p_todo, offset)

topydo/lib/RelativeDate.py

@@ -35,13 +35,14 @@ def _add_months(p_sourcedate, p_months):
 
     return date(year, month, day)
 
-def _convert_pattern(p_length, p_periodunit, p_offset=date.today()):
+def _convert_pattern(p_length, p_periodunit, p_offset=None):
     """
     Converts a pattern in the form [0-9][dwmy] and returns a date from today
     with the period of time added to it.
     """
     result = None
 
+    p_offset = p_offset or date.today()
     p_length = int(p_length)
 
     if p_periodunit == 'd':
@@ -80,7 +81,7 @@ def _convert_weekday_pattern(p_weekday):
     shift = (target_day - day) % 7
     return date.today() + timedelta(shift)
 
-def relative_date_to_date(p_date, p_offset=date.today()):
+def relative_date_to_date(p_date, p_offset=None):
     """
     Transforms a relative date into a date object.
 
@@ -93,6 +94,7 @@ def relative_date_to_date(p_date, p_offset=date.today()):
 
     result = None
     p_date = p_date.lower()
+    p_offset = p_offset or date.today()
 
     relative = re.match('(?P<length>-?[0-9]+)(?P<period>[dwmy])$', p_date, re.I)