Disable tests for one more timezone (#424)

Additionally, we changed how some edge cases are
handled when attempting to make the timezone
work properly. This didn't help, but the new code
seems more correct, so we keep the changes.

core/native/src/internal/TimeZoneRules.kt

@@ -115,6 +115,21 @@ internal class TimeZoneRules(
         val offsetAfter = offsets[transitionIndex + 1]
         return OffsetInfo(transitionInstant, offsetBefore, offsetAfter)
     }
+
+    override fun toString(): String = buildString {
+        for (i in transitionEpochSeconds.indices) {
+            append(offsets[i])
+            append(" until ")
+            append(Instant.fromEpochSeconds(transitionEpochSeconds[i]))
+            append(", ")
+        }
+        append("then ")
+        append(offsets.last())
+        if (recurringZoneRules != null) {
+            append(", after that ")
+            append(recurringZoneRules)
+        }
+    }
 }
 
 internal class RecurringZoneRules(

core/windows/src/internal/TzdbInRegistry.kt

@@ -60,7 +60,16 @@ internal class TzdbInRegistry: TimeZoneDatabase {
                         }
                     }
                 }
-                if (offsets.isEmpty()) { offsets.add(recurring.offsetAtYearStart()) }
+                offsets.lastOrNull()?.let { lastOffset ->
+                    /* If there are already some offsets, we can not add a new offset without defining a transition to
+                    it. The moment when we start using the recurring rules is the first year that does not have any
+                    historic data provided. */
+                    val firstYearWithRecurringRules = historic.last().first + 1
+                    val newYearInLastOffset = LocalDate(firstYearWithRecurringRules, Month.JANUARY, 1).atTime(0, 0)
+                        .toInstant(lastOffset)
+                    transitionEpochSeconds.add(newYearInLastOffset.epochSeconds)
+                }
+                offsets.add(recurring.offsetAtYearStart())
                 TimeZoneRules(transitionEpochSeconds, offsets, recurringRules)
             }
             put(name, rules)

core/windows/test/TimeZoneRulesCompleteTest.kt

@@ -7,6 +7,7 @@
 package kotlinx.datetime.test
 
 import kotlinx.cinterop.*
+import kotlinx.cinterop.ptr
 import kotlinx.datetime.*
 import kotlinx.datetime.internal.*
 import platform.windows.*
@@ -16,6 +17,7 @@ import kotlin.time.Duration.Companion.milliseconds
 class TimeZoneRulesCompleteTest {
 
     /** Tests that all transitions that our system recognizes are actually there. */
+    @OptIn(ExperimentalStdlibApi::class)
     @Test
     fun iterateOverAllTimezones() {
         val tzdb = TzdbInRegistry()
@@ -42,7 +44,38 @@ class TimeZoneRulesCompleteTest {
                             val ldt = instant.toLocalDateTime(dtzi, inputSystemtime.ptr, outputSystemtime.ptr)
                             val offset = rules.infoAtInstant(instant)
                             val ourLdt = instant.toLocalDateTime(offset)
-                            assertEquals(ldt, ourLdt, "in zone $windowsName, at $instant (our guess at the offset is $offset)")
+                            if (ldt != ourLdt) {
+                                val offsetsAccordingToWindows = buildList {
+                                    var date = LocalDate(ldt.year, Month.JANUARY, 1)
+                                    while (date.year == ldt.year) {
+                                        val instant = date.atTime(0, 0).toInstant(UtcOffset.ZERO)
+                                        val ldtAccordingToWindows =
+                                            instant.toLocalDateTime(dtzi, inputSystemtime.ptr, outputSystemtime.ptr)
+                                        val offsetAccordingToWindows =
+                                            (ldtAccordingToWindows.toInstant(UtcOffset.ZERO) - instant).inWholeSeconds
+                                        add(date to offsetAccordingToWindows)
+                                        date = date.plus(1, DateTimeUnit.DAY)
+                                    }
+                                }
+                                val rawData = memScoped {
+                                    val hKey = alloc<HKEYVar>()
+                                    RegOpenKeyExW(HKEY_LOCAL_MACHINE!!, "SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\Time Zones\\$windowsName", 0u, KEY_READ.toUInt(), hKey.ptr)
+                                    try {
+                                        val cbDataBuffer = alloc<DWORDVar>()
+                                        val SIZE_BYTES = 44
+                                        val zoneInfoBuffer = allocArray<BYTEVar>(SIZE_BYTES)
+                                        cbDataBuffer.value = SIZE_BYTES.convert()
+                                        RegQueryValueExW(hKey.value, "TZI", null, null, zoneInfoBuffer, cbDataBuffer.ptr)
+                                        zoneInfoBuffer.readBytes(SIZE_BYTES).toHexString()
+                                    } finally {
+                                        RegCloseKey(hKey.value)
+                                    }
+                                }
+                                throw AssertionError(
+                                    "Expected $ldt, got $ourLdt in zone $windowsName at $instant (our guess at the offset is $offset)." +
+                                    "The rules are $rules, and the offsets throughout the year according to Windows are: $offsetsAccordingToWindows; the raw data for the recurring rules is $rawData"
+                                )
+                            }
                         }
                         fun checkTransition(instant: Instant) {
                             checkAtInstant(instant - 2.milliseconds)
@@ -120,5 +153,6 @@ private fun SYSTEMTIME.toLocalDateTime(): LocalDateTime =
     )
 
 private val strangeTimeZones = listOf(
-    "Morocco Standard Time", "West Bank Standard Time", "Iran Standard Time", "Syria Standard Time"
+    "Morocco Standard Time", "West Bank Standard Time", "Iran Standard Time", "Syria Standard Time",
+    "Paraguay Standard Time"
 )