TW-1700: modify tags behavior changed

- Thanks to David Badura.

AUTHORS

@@ -275,3 +275,4 @@ suggestions:
   Marc Cornellà
   Ander
   Naga Kiran
+  David Badura

ChangeLog

@@ -159,6 +159,7 @@
 - TW-1692 '42//' segfaults (thanks to Daniel Shahaf).
 - TW-1695 edit: Concurrent edits (thanks to Daniel Shahaf).
 - TW-1699 Command interpretation displayed incorrectly (thanks to Tomas Babej).
+- TW-1700 modify tags behavior changed (thanks to David Badura).
 - TW-1701 Some generated UUIDs deemed invalid (thanks to Wim Schuermann).
 - Prevent potential task duplication during import for non-pending tasks.
 - Show the active context in "context list", if any is active.

src/Task.cpp

@@ -2060,6 +2060,9 @@ void Task::modify (modType type, bool text_required /* = false */)
           // For those using the "tags:..." attribute directly.
           else if (name == "tags")
           {
+            // TW-1701
+            set ("tags", "");
+
             std::vector <std::string> tags;
             split (tags, value, ',');
 

test/tag.t

@@ -488,6 +488,23 @@ class TestListAllTags(TestCase):
         self.assertIn("t2", out)
 
 
+class TestBug1700(TestCase):
+    def setUp(self):
+        self.t = Task()
+
+    def test_tags_overwrite(self):
+        """Verify that 'tags:a,b' overwrites existing tags."""
+        self.t("add +tag1 +tag2 one")
+        code, out, err = self.t("_get 1.tags")
+        self.assertIn("tag1,tag2", out)
+        self.assertNotIn("tag3", out)
+
+        self.t("1 modify tags:tag2,tag3")
+        code, out, err = self.t("_get 1.tags")
+        self.assertNotIn("tag1", out)
+        self.assertIn("tag2,tag3", out)
+
+
 if __name__ == "__main__":
     from simpletap import TAPTestRunner
     unittest.main(testRunner=TAPTestRunner())