Enhancement

- Importing the same YAML twice now generates an error.

ChangeLog

@@ -41,6 +41,7 @@
  + New fish shell tab completion script (thanks to Mick Koch).
  + Color rules now obey the rc.search.case.sensitive configuration option.
  + The color.keyword.XXX color rule now applies to annotations too.
+ + Importing the same YAML twice now generates an error.
  + Fixed bug #427, preventing the task edit command to parse annotation
    dates with spaces.
  + Fixed bug #433, making task command output more consistent.

NEWS

@@ -13,7 +13,8 @@ New Features in taskwarrior 1.9.3
   - Now supports 'now' as a date/time.
   - Now defines an overdue task as being one second after the due date,
     instead of the day after the due date.
-  - Import and export of YAML 1.1, including round-trip capability.
+  - Import and export of YAML 1.1, including round-trip capability, and
+    detection of duplicate imports.
   - New merge capability for syncing task data files.
   - New push capability for distributing merged changes.
   - When completing or modifying a task, the project status is displayed.

src/TDB.cpp

@@ -463,17 +463,25 @@ const std::vector <Task>& TDB::getAllModified ()
 // Note: mLocations[0] is where all tasks are written.
 void TDB::add (const Task& task)
 {
+  std::string unique;
   Task t (task);
   if (task.get ("uuid") == "")
-  {
-    std::string unique = ::uuid ();
-    t.set ("uuid", unique);
-  }
+    unique = ::uuid ();
   else
-   t.set ("uuid", task.get ("uuid"));
+    unique = task.get ("uuid");
+
+  t.set ("uuid", unique);
+
+  // If the tasks are loaded, then verify that this uuid is not already in
+  // the file.
+  if (uuidAlreadyUsed (unique, mNew)      ||
+      uuidAlreadyUsed (unique, mModified) ||
+      uuidAlreadyUsed (unique, mPending)  ||
+      uuidAlreadyUsed (unique, mCompleted))
+    throw std::string ("Cannot add task because the uuid '") + unique + "' is not unique.";
 
   mNew.push_back (t);
-  mI2U[task.id] = t.get ("uuid");
+  mI2U[task.id] = unique;
   mU2I[task.get ("uuid")] = t.id;
 }
 
@@ -1610,3 +1618,16 @@ void TDB::writeUndo (const Task& before, const Task& after, FILE* file)
 }
 
 ////////////////////////////////////////////////////////////////////////////////
+bool TDB::uuidAlreadyUsed (
+  const std::string& uuid,
+  const std::vector <Task>& all)
+{
+  std::vector <Task>::const_iterator it;
+  for (it = all.begin (); it != all.end (); ++it)
+    if (it->get ("uuid") == uuid)
+      return true;
+
+  return false;
+}
+
+////////////////////////////////////////////////////////////////////////////////

src/TDB.h

@@ -76,6 +76,8 @@ private:
   FILE* openAndLock (const std::string&);
   void writeUndo (const Task&, FILE*);
   void writeUndo (const Task&, const Task&, FILE*);
+  bool uuidAlreadyUsed (const std::string&);
+  bool uuidAlreadyUsed (const std::string&, const std::vector <Task>&);
 
 private:
   std::vector <Location> mLocations;

src/import.cpp

@@ -1169,6 +1169,11 @@ static std::string importYAML (const std::vector <std::string>& lines)
 
   context.tdb.lock (context.config.getBoolean ("locking"));
 
+  // Load all the tasks so that the uuid uniqueness can be checked.
+  std::vector <Task> tasks;
+  Filter filter;
+  context.tdb.load (tasks, filter);
+
   Task t;
 
   std::string name;

src/tests/import.yaml.t

@@ -28,7 +28,7 @@
 
 use strict;
 use warnings;
-use Test::More tests => 14;
+use Test::More tests => 15;
 
 # Create the rc file.
 if (open my $fh, '>', 'import.rc')
@@ -96,6 +96,10 @@ unlike ($output, qr/1.+A.+zero/,       't1 missing');
 unlike ($output, qr/2.+B.+one/,        't2 missing');
 like   ($output, qr/2\/13\/2009.+two/, 't3 present');
 
+# Make sure that a duplicate task cannot be imported.
+$output = qx{../task rc:import.rc import import.txt};
+like ($output, qr/Cannot add task because the uuid .+ is not unique\./, 'error on duplicate uuid');
+
 # Cleanup.
 unlink 'import.txt';
 ok (!-r 'import.txt', 'Removed import.txt');