Task

- Now that ::composeF4 guarantees not to write out attributes with blank values,
  we can use blank values to indicate that blanks were specified on the command
  line, and avoid apllication of defaults.

src/Task.cpp

@@ -1458,14 +1458,14 @@ void Task::validate (bool applyDefault /* = true */)
 
   // 1) Provide missing attributes where possible
   // Provide a UUID if necessary.
-  if (! has ("uuid"))
+  if (! has ("uuid") || get ("uuid") == "")
     set ("uuid", uuid ());
 
   // Recurring tasks get a special status.
   if (status == Task::pending &&
       has ("due")             &&
       has ("recur")           &&
-      ! has ("parent"))
+      (! has ("parent") || get ("parent") == ""))
     status = Task::recurring;
 
   // Tasks with a wait: date get a special status.
@@ -1474,7 +1474,7 @@ void Task::validate (bool applyDefault /* = true */)
     status = Task::waiting;
 
   // By default, tasks are pending.
-  else if (! has ("status"))
+  else if (! has ("status") || get ("status") == "")
     status = Task::pending;
 
   // Store the derived status.
@@ -1482,36 +1482,38 @@ void Task::validate (bool applyDefault /* = true */)
 
 #ifdef PRODUCT_TASKWARRIOR
   // Provide an entry date unless user already specified one.
-  if (!has ("entry"))
+  if (!has ("entry") || get ("entry") == "")
     setEntry ();
 
   // Completed tasks need an end date, so inherit the entry date.
-  if (! has ("end") &&
-      (getStatus () == Task::completed ||
-       getStatus () == Task::deleted))
+  if ((status == Task::completed || status == Task::deleted) &&
+      (! has ("end") || get ("end") == ""))
     setEnd ();
 
   // Override with default.project, if not specified.
-  if (applyDefault && ! has ("project"))
+  if (applyDefault               &&
+      Task::defaultProject != "" &&
+      (! has ("project") || get ("project") == ""))
   {
-    if (Task::defaultProject != "" &&
-        context.columns["project"]->validate (Task::defaultProject))
+    if (context.columns["project"]->validate (Task::defaultProject))
       set ("project", Task::defaultProject);
   }
 
   // Override with default.priority, if not specified.
-  if (applyDefault && get ("priority") == "")
+  if (applyDefault                &&
+      Task::defaultPriority != "" &&
+      (! has ("priority") || get ("priority") == ""))
   {
-    if (Task::defaultPriority != "" &&
-        context.columns["priority"]->validate (Task::defaultPriority))
+    if (context.columns["priority"]->validate (Task::defaultPriority))
       set ("priority", Task::defaultPriority);
   }
 
   // Override with default.due, if not specified.
-  if (applyDefault && get ("due") == "")
+  if (applyDefault &&
+      Task::defaultDue != "" &&
+      (! has ("due") || get ("due") == ""))
   {
-    if (Task::defaultDue != "" &&
-        context.columns["due"]->validate (Task::defaultDue))
+    if (context.columns["due"]->validate (Task::defaultDue))
       set ("due", Date (Task::defaultDue).toEpoch ());
   }