From 954955794592b1ae6ac14f3a1c606d53c5b9db50 Mon Sep 17 00:00:00 2001
From: Carl de Billy <carl.debilly@nventive.com>
Date: Thu, 3 Jun 2021 11:02:52 -0400
Subject: [PATCH] fix(calendar): Fixed a potential crash when
 `SetToMin()`/`SetToMax()` were used in multi-eras calendars

---
 .../CalendarViewIntegrationTests.cs           |  2 -
 .../Windows_Globalization/When_Calendar.cs    | 49 +++++++++++++++++++
 src/Uno.UWP/Globalization/Calendar.cs         | 20 ++++----
 3 files changed, 59 insertions(+), 12 deletions(-)

diff --git a/src/Uno.UI.RuntimeTests/IntegrationTests/dxaml/controls/calendarview/CalendarViewIntegrationTests.cs b/src/Uno.UI.RuntimeTests/IntegrationTests/dxaml/controls/calendarview/CalendarViewIntegrationTests.cs
index c62bdebdfb29..169e709360a9 100644
--- a/src/Uno.UI.RuntimeTests/IntegrationTests/dxaml/controls/calendarview/CalendarViewIntegrationTests.cs
+++ b/src/Uno.UI.RuntimeTests/IntegrationTests/dxaml/controls/calendarview/CalendarViewIntegrationTests.cs
@@ -282,8 +282,6 @@ public async Task CanSelectOutOfRangeDate()
 
 			rootPanel = await CalendarHelper.CreateTestResources();
 
-
-
 			// load into visual tree
 			await RunOnUIThread(() =>
 			{
diff --git a/src/Uno.UI.Tests/Windows_Globalization/When_Calendar.cs b/src/Uno.UI.Tests/Windows_Globalization/When_Calendar.cs
index 4b7b596577f4..7ec4070b3c47 100644
--- a/src/Uno.UI.Tests/Windows_Globalization/When_Calendar.cs
+++ b/src/Uno.UI.Tests/Windows_Globalization/When_Calendar.cs
@@ -695,5 +695,54 @@ string dayOfWeekAsString
 				SUT.DayOfWeekAsString().Should().Be(dayOfWeekAsString, nameof(dayOfWeekAsString));
 			}
 		}
+
+		[TestMethod]
+		[DataRow(WG.CalendarIdentifiers.JulianValue)]
+		[DataRow(WG.CalendarIdentifiers.GregorianValue)]
+		[DataRow(WG.CalendarIdentifiers.HebrewValue)]
+		[DataRow(WG.CalendarIdentifiers.HijriValue)]
+		[DataRow(WG.CalendarIdentifiers.JapaneseValue)]
+		[DataRow(WG.CalendarIdentifiers.KoreanValue)]
+		[DataRow(WG.CalendarIdentifiers.TaiwanValue)]
+		[DataRow(WG.CalendarIdentifiers.ThaiValue)]
+		[DataRow(WG.CalendarIdentifiers.UmAlQuraValue)]
+		[DataRow(WG.CalendarIdentifiers.PersianValue)]
+		[DataRow(WG.CalendarIdentifiers.ChineseLunarValue)]
+		[DataRow(WG.CalendarIdentifiers.VietnameseLunarValue)]
+		[DataRow(WG.CalendarIdentifiers.TaiwanLunarValue)]
+		[DataRow(WG.CalendarIdentifiers.KoreanLunarValue)]
+		[DataRow(WG.CalendarIdentifiers.JapaneseLunarValue)]
+		public void TestCalendarLimits(string calendar)
+		{
+			using var _ = new AssertionScope();
+
+			var sut = new WG.Calendar(new [] {"en"}, WG.CalendarIdentifiers.Japanese, "24HourClock");
+
+			sut.SetToMin();
+			CheckLimits($"Min");
+
+			sut.SetToMax();
+			CheckLimits($"Max");
+
+			sut.SetToNow();
+			CheckLimits($"Max");
+
+			void CheckLimits(string context)
+			{
+				// Following tests are just to ensure no exceptions are raised
+				// by asking those values
+				sut.NumberOfEras.Should().BePositive(context);
+				sut.Era.Should().BePositive(context);
+				sut.FirstMonthInThisYear.Should().BePositive(context);
+				sut.NumberOfDaysInThisMonth.Should().BePositive(context);
+				sut.DayOfWeek.Should().NotBeNull(context);
+				sut.NumberOfEras.Should().BePositive(context);
+				sut.FirstEra.Should().BePositive(context);
+				sut.LastEra.Should().BePositive(context);
+				sut.Period.Should().BePositive(context);
+				sut.ResolvedLanguage.Should().NotBeEmpty(context);
+			}
+		}
 	}
 }
+
diff --git a/src/Uno.UWP/Globalization/Calendar.cs b/src/Uno.UWP/Globalization/Calendar.cs
index 2da6e3e84a5d..e83477522363 100644
--- a/src/Uno.UWP/Globalization/Calendar.cs
+++ b/src/Uno.UWP/Globalization/Calendar.cs
@@ -188,27 +188,27 @@ public void ChangeTimeZone(string timeZoneId)
 		#region Read / Write _time
 		public int Era
 		{
-			get => _calendar.GetEra(_time.DateTime);
+			get => _calendar.GetEra(_time.UtcDateTime);
 			[NotImplemented] set => global::Windows.Foundation.Metadata.ApiInformation.TryRaiseNotImplemented("Windows.Globalization.Calendar", "int Calendar.Era");
 		}
 
 		public int Year
 		{
-			get => _calendar.GetYear(_time.DateTime);
+			get => _calendar.GetYear(_time.UtcDateTime);
 			set => AddYears(value - Year);
 		}
 
 		public int Month
 		{
-			get => _calendar.GetMonth(_time.DateTime);
+			get => _calendar.GetMonth(_time.UtcDateTime);
 			set => AddMonths(value - Month);
 		}
 
-		public global::Windows.Globalization.DayOfWeek DayOfWeek => (global::Windows.Globalization.DayOfWeek)_calendar.GetDayOfWeek(_time.DateTime);
+		public global::Windows.Globalization.DayOfWeek DayOfWeek => (global::Windows.Globalization.DayOfWeek)_calendar.GetDayOfWeek(_time.UtcDateTime);
 
 		public int Day
 		{
-			get => _calendar.GetDayOfMonth(_time.DateTime);
+			get => _calendar.GetDayOfMonth(_time.UtcDateTime);
 			set => AddDays(value - Day);
 		}
 
@@ -216,7 +216,7 @@ public int Hour
 		{
 			get
 			{
-				var hour = _calendar.GetHour(_time.DateTime);
+				var hour = _calendar.GetHour(_time.UtcDateTime);
 
 				if(hour < 12 || _clock == ClockIdentifiers.TwentyFourHour)
 				{
@@ -233,13 +233,13 @@ public int Hour
 
 		public int Minute
 		{
-			get => _calendar.GetMinute(_time.DateTime);
+			get => _calendar.GetMinute(_time.UtcDateTime);
 			set => AddMinutes(value - Minute);
 		}
 
 		public int Second
 		{
-			get => _calendar.GetSecond(_time.DateTime);
+			get => _calendar.GetSecond(_time.UtcDateTime);
 			set => AddSeconds(value - Second);
 		}
 
@@ -278,7 +278,7 @@ public int Period
 
 		public int Nanosecond
 		{
-			get => (int)(_calendar.GetMilliseconds(_time.DateTime) * 1000);
+			get => (int)(_calendar.GetMilliseconds(_time.UtcDateTime) * 1000);
 			set => AddNanoseconds(value - Nanosecond);
 		}
 
@@ -286,7 +286,7 @@ public void SetDateTime(global::System.DateTimeOffset value)
 			=> _time = value;
 
 		public void SetToNow()
-			=> _time = DateTime.Now;
+			=> _time = DateTimeOffset.Now;
 
 		internal void SetToday() // Useful helper not part of UWP contract
 			=> _time = DateTime.Today;