Events: add VALUE=DATE to EXDATE for cancelled all-day exceptions (#441)

* Add VALUE=DATE to EXDATE for cancelled all-day exceptions

* RecurrenceFieldHandler: test VALUE=DATE for all-day EXDATE

Author: rfc2822

lib/src/main/kotlin/at/bitfire/synctools/mapping/calendar/AndroidEventHandler.kt

@@ -42,6 +42,7 @@ import net.fortuna.ical4j.model.ParameterList
 import net.fortuna.ical4j.model.Property
 import net.fortuna.ical4j.model.component.VEvent
 import net.fortuna.ical4j.model.parameter.TzId
+import net.fortuna.ical4j.model.parameter.Value
 import net.fortuna.ical4j.model.property.ExDate
 import net.fortuna.ical4j.model.property.ProdId
 import net.fortuna.ical4j.model.property.RDate
@@ -166,7 +167,7 @@ class AndroidEventHandler(
         // Return ExDate
         return if (originalAllDay) {
             // .. as date, without time
-            ExDate(DateList(LocalDate.from(date)))
+            ExDate(ParameterList(listOf(Value.DATE)), DateList(LocalDate.from(date)))
         } else if (date is Instant) {
             ExDate(DateList(date))
         } else {

lib/src/test/kotlin/at/bitfire/synctools/mapping/calendar/AndroidEventHandlerTest.kt

@@ -11,13 +11,15 @@ import android.provider.CalendarContract.Events
 import android.provider.CalendarContract.ExtendedProperties
 import androidx.core.content.contentValuesOf
 import at.bitfire.dateTimeValue
+import at.bitfire.dateValue
 import at.bitfire.synctools.icalendar.dtStart
 import at.bitfire.synctools.icalendar.recurrenceId
 import at.bitfire.synctools.storage.calendar.EventAndExceptions
 import at.bitfire.synctools.storage.calendar.EventsContract
-import at.bitfire.synctools.util.AndroidTimeUtils
+import net.fortuna.ical4j.model.Parameter
 import net.fortuna.ical4j.model.Property
 import net.fortuna.ical4j.model.TimeZoneRegistryFactory
+import net.fortuna.ical4j.model.parameter.Value
 import net.fortuna.ical4j.model.property.DtStart
 import net.fortuna.ical4j.model.property.ExDate
 import net.fortuna.ical4j.model.property.ProdId
@@ -148,6 +150,43 @@ class AndroidEventHandlerTest {
         assertTrue(result.exceptions.isEmpty())
     }
 
+    @Test
+    fun `mapToVEvents rewrites cancelled all-day exception to EXDATE with VALUE=DATE`() {
+        val result = handler.mapToVEvents(
+            eventAndExceptions = EventAndExceptions(
+                main = Entity(contentValuesOf(
+                    Events.TITLE to "Recurring all-day event with cancelled all-day exception",
+                    Events.DTSTART to 1594056600000L,
+                    Events.EVENT_TIMEZONE to "UTC",
+                    Events.ALL_DAY to 1,    // main event is all-day
+                    Events.RRULE to "FREQ=DAILY;COUNT=10"
+                )),
+                exceptions = listOf(
+                    Entity(contentValuesOf(
+                        Events.ORIGINAL_INSTANCE_TIME to 1594143000000L,
+                        Events.ORIGINAL_ALL_DAY to 1,    // exception is all-day
+                        Events.DTSTART to 1594143000000L,
+                        Events.ALL_DAY to 1,
+                        Events.EVENT_TIMEZONE to "UTC",
+                        Events.STATUS to Events.STATUS_CANCELED
+                    ))
+                )
+            )
+        ).associatedEvents
+        val main = result.main!!
+        assertEquals("Recurring all-day event with cancelled all-day exception", main.summary.value)
+        assertEquals("FREQ=DAILY;COUNT=10", main.getProperty<RRule<*>>(Property.RRULE).get().value)
+
+        // Check that EXDATE has VALUE=DATE
+        val exDate = main.getProperty<ExDate<*>>(Property.EXDATE).get()
+        assertEquals(Value.DATE, exDate.getParameter<Value>(Parameter.VALUE).get())
+        assertEquals(
+            dateValue("20200707"),
+            main.getProperty<ExDate<*>>(Property.EXDATE)?.getOrNull()?.dates?.first()
+        )
+        assertTrue(result.exceptions.isEmpty())
+    }
+
     @Test
     fun `mapToVEvents rewrites cancelled exception using UTC to EXDATE`() {
         val result = handler.mapToVEvents(

lib/src/test/kotlin/at/bitfire/synctools/mapping/calendar/handler/RecurrenceFieldHandlerTest.kt

@@ -15,6 +15,7 @@ import at.bitfire.dateValue
 import io.mockk.mockk
 import junit.framework.TestCase.assertEquals
 import net.fortuna.ical4j.model.DateList
+import net.fortuna.ical4j.model.Parameter
 import net.fortuna.ical4j.model.ParameterList
 import net.fortuna.ical4j.model.Property
 import net.fortuna.ical4j.model.Recur
@@ -132,10 +133,10 @@ class RecurrenceFieldHandlerTest {
             "FREQ=WEEKLY;COUNT=1",
             result.getProperties<ExRule<Temporal>>(Property.EXRULE).joinToString { it.value }
         )
-        assertEquals(
-            "20260201",
-            result.getProperties<ExDate<Temporal>>(Property.EXDATE).joinToString { it.value }
-        )
+        // All-day EXDATE must have VALUE=DATE
+        val exDates = result.getProperties<ExDate<Temporal>>(Property.EXDATE)
+        assertEquals(Value.DATE, exDates.first().getParameter<Value>(Parameter.VALUE).get())
+        assertEquals("20260201", exDates.joinToString { it.value })
     }
 
     @Test