simplify how the local offset is passed around

- no need to store it in conf
- move local_minutes_west() call to collection

pylib/anki/collection.py

@@ -138,10 +138,6 @@ class _Collection:
             self.sched = V1Scheduler(self)
         elif ver == 2:
             self.sched = V2Scheduler(self)
-            if not self.server:
-                self.conf["localOffset"] = self.sched._current_timezone_offset()
-            elif self.server.minutes_west is not None:
-                self.conf["localOffset"] = self.server.minutes_west
 
     def changeSchedulerVer(self, ver: int) -> None:
         if ver == self.schedVer():
@@ -164,12 +160,13 @@ class _Collection:
 
         self._loadScheduler()
 
+    # the sync code uses this to send the local timezone to AnkiWeb
     def localOffset(self) -> Optional[int]:
         "Minutes west of UTC. Only applies to V2 scheduler."
         if isinstance(self.sched, V1Scheduler):
             return None
         else:
-            return self.sched._current_timezone_offset()
+            return self.backend.local_minutes_west(intTime())
 
     # DB-related
     ##########################################################################

pylib/anki/schedv2.py

@@ -1392,14 +1392,16 @@ where id = ?
             self._rolloverHour(),
         )
 
-    def _current_timezone_offset(self) -> int:
+    def _current_timezone_offset(self) -> Optional[int]:
         if self.col.server:
-            return self.col.conf.get("localOffset", None)
+            mins = self.col.server.minutes_west
+            if mins is not None:
+                return mins
+            # older Anki versions stored the local offset in
+            # the config
+            return self.col.conf.get("localOffset", 0)
         else:
-            # note: while we could return None to sched_timing_today to have
-            # the backend calculate it, this function is also used to set
-            # localOffset, so it must not return None
-            return self.col.backend.local_minutes_west(intTime())
+            return None
 
     def _creation_timezone_offset(self) -> Optional[int]:
         return self.col.conf.get("creationOffset", None)