allow strings instead of tuples as input for sort_keys in search.

Updates #448

CHANGELOG.md

@@ -10,6 +10,12 @@ The format of this file should adhere to [Keep a Changelog](https://keepachangel
 
 This project should more or less adhere to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+### Added
+
+* By now `calendar.search(..., sort_keys=("DTSTART")` will work.  Sort keys expects a list or a tuple, but it's easy to send an attribute by mistake.
+
 ## [1.4.0] - 2024-11-05
 
 * Lots of work lifting the project up to more modern standards and improving code, thanks to Georges Toth (github @sim0nx), Matthias Urlichs (github @smurfix) and @ArtemIsmagilov.  While this shouldn't matter for existing users, it will make the library more future-proof.

caldav/objects.py

@@ -1311,6 +1311,7 @@ def sort_key_func(x):
                     > datetime.now().strftime("%F%H%M%S")
                 ),
             }
+            ## ref https://github.com/python-caldav/caldav/issues/448 - allow strings instead of a sequence here
             for sort_key in sort_keys:
                 val = comp.get(sort_key, None)
                 if val is None:
@@ -1327,6 +1328,8 @@ def sort_key_func(x):
             return ret
 
         if sort_keys:
+            if isinstance(sort_keys, str):
+                sort_keys = (sort_keys,)
             objects.sort(key=sort_key_func, reverse=sort_reverse)
 
         ## partial workaround for https://github.com/python-caldav/caldav/issues/201

tests/test_caldav.py

@@ -1500,6 +1500,40 @@ def testSearchEvent(self):
         assert len(all_events) == 3
         assert all_events[0].instance.vevent.summary.value == "Our Blissful Anniversary"
 
+        ## A more robust check for the sort key
+        all_events = c.search(sort_keys=("DTSTART",))
+        assert len(all_events) == 3
+        assert str(all_events[0].icalendar_component["DTSTART"].dt) < str(
+            all_events[1].icalendar_component["DTSTART"].dt
+        )
+        assert str(all_events[1].icalendar_component["DTSTART"].dt) < str(
+            all_events[2].icalendar_component["DTSTART"].dt
+        )
+        all_events = c.search(sort_keys=("DTSTART",), sort_reverse=True)
+        assert str(all_events[0].icalendar_component["DTSTART"].dt) > str(
+            all_events[1].icalendar_component["DTSTART"].dt
+        )
+        assert str(all_events[1].icalendar_component["DTSTART"].dt) > str(
+            all_events[2].icalendar_component["DTSTART"].dt
+        )
+
+        ## Ref https://github.com/python-caldav/caldav/issues/448
+        all_events = c.search(sort_keys=("DTSTART"))
+        assert len(all_events) == 3
+        assert str(all_events[0].icalendar_component["DTSTART"].dt) < str(
+            all_events[1].icalendar_component["DTSTART"].dt
+        )
+        assert str(all_events[1].icalendar_component["DTSTART"].dt) < str(
+            all_events[2].icalendar_component["DTSTART"].dt
+        )
+        all_events = c.search(sort_keys=("DTSTART"), sort_reverse=True)
+        assert str(all_events[0].icalendar_component["DTSTART"].dt) > str(
+            all_events[1].icalendar_component["DTSTART"].dt
+        )
+        assert str(all_events[1].icalendar_component["DTSTART"].dt) > str(
+            all_events[2].icalendar_component["DTSTART"].dt
+        )
+
     def testSearchSortTodo(self):
         self.skip_on_compatibility_flag("read_only")
         self.skip_on_compatibility_flag("no_todo")