Update "modified" on modification

src/TDB2.cpp

@@ -133,6 +133,9 @@ void TDB2::add (Task& task)
 // they have been unmodified for a long time.
 void TDB2::modify (Task& task)
 {
+  // All locally modified tasks are timestamped, implicitly overwriting any
+  // changes the user or hooks tried to apply to the "modified" attribute.
+  task.setAsNow ("modified");
   task.validate (false);
   auto uuid = task.get ("uuid");
 

src/Task.cpp

@@ -1826,7 +1826,7 @@ void Task::validate (bool applyDefault /* = true */)
   if ((status == Task::pending) && (get ("end") != ""))
     remove ("end");
 
-  // Provide an entry date unless user already specified one.
+  // Provide a modified date unless user already specified one.
   if (! has ("modified") || get ("modified") == "")
     setAsNow ("modified");
 

test/tw-3102.t

@@ -0,0 +1,13 @@
+#!/usr/bin/env bash
+. bash_tap_tw.sh
+
+task add modtest modified:yesterday
+old_modified=`task _get 1.modified`
+echo $old_modified
+
+task 1 start
+new_modified=`task _get 1.modified`
+echo $new_modified
+
+# `task start` should have updated modified
+[[ $old_modified != $new_modified ]]