fix of two minor misbehaviors in date-time handling (#3248)

app/src/main/java/org/tasks/compose/pickers/DatePickerDialog.kt

@@ -25,7 +25,11 @@ fun DatePickerDialog(
 ) {
     val initialDateUTC by remember(initialDate) {
         derivedStateOf {
-            DateTime(initialDate).toUTC().millis
+            // DateTime(initialDate).toUTC().millis
+            // DateTime.toUTC() does not change DateTime.millis value, but DatePicker expects it
+            // is in local timezone and decrements it by TimeZone.offset. This shifts the date to
+            // the previous date in timezones to East of GMT, which is unexpected
+            DateTime(initialDate).let { it.millis + it.offset }
         }
     }
     val datePickerState = rememberDatePickerState(

app/src/main/java/org/tasks/repeats/CustomRecurrenceViewModel.kt

@@ -172,7 +172,11 @@ class CustomRecurrenceViewModel @Inject constructor(
             builder.interval(state.interval)
         }
         when (state.endSelection) {
-            1 -> builder.until(Date(state.endDate))
+            // 1 -> builder.until(Date(state.endDate))
+            // builder.until expects that Date() is in local timezone and strips it, which effectively
+            // equivalent to decrementing the "endDate" value by TimeZone.offset. This changes the date
+            // to the previous day in timezones to the East of GMT, so this value shall be pre-shifted
+            1 -> builder.until(Date(DateTime(state.endDate).let { it.millis + it.offset }))
             2 -> builder.count(state.endCount.coerceAtLeast(1))
         }
         return builder.build().toString()