Update Value of TwoDigitYearMax to 2049

src/libraries/System.Globalization.Calendars/tests/ThaiBuddhistCalendar/ThaiBuddhistCalendarToFourDigitYear.cs

@@ -16,12 +16,12 @@ public class ThaiBuddhistCalendarToFourDigitYear
         public void ToFourDigitYear(int year)
         {
             ThaiBuddhistCalendar calendar = new ThaiBuddhistCalendar();
-            calendar.TwoDigitYearMax = 2029;
+            calendar.TwoDigitYearMax = 2049;
             if (year > 99)
             {
                 Assert.Equal(year, calendar.ToFourDigitYear(year));
             }
-            else if (year > 29)
+            else if (year > 49)
             {
                 Assert.Equal(year + 1900, calendar.ToFourDigitYear(year));
             }

src/libraries/System.Private.CoreLib/src/System/Globalization/Calendar.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.Diagnostics;
+using System.Runtime.InteropServices;
 
 namespace System.Globalization
 {
@@ -650,10 +651,10 @@ internal virtual bool IsValidDay(int year, int month, int day, int era)
         /// Returns and assigns the maximum value to represent a two digit year.
         /// This value is the upper boundary of a 100 year range that allows a
         /// two digit year to be properly translated to a four digit year.
-        /// For example, if 2029 is the upper boundary, then a two digit value of
-        /// 30 should be interpreted as 1930 while a two digit value of 29 should
-        /// be interpreted as 2029.  In this example, the 100 year range would be
-        /// from 1930-2029.  See ToFourDigitYear().
+        /// For example, if 2049 is the upper boundary, then a two digit value of
+        /// 30 should be interpreted as 1950 while a two digit value of 49 should
+        /// be interpreted as 2049.  In this example, the 100 year range would be
+        /// from 1950-2049.  See ToFourDigitYear().
         /// </summary>
         public virtual int TwoDigitYearMax
         {
@@ -667,9 +668,9 @@ public virtual int TwoDigitYearMax
 
         /// <summary>
         /// Converts the year value to the appropriate century by using the
-        /// TwoDigitYearMax property.  For example, if the TwoDigitYearMax value is 2029,
-        /// then a two digit value of 30 will get converted to 1930 while a two digit
-        /// value of 29 will get converted to 2029.
+        /// TwoDigitYearMax property.  For example, if the TwoDigitYearMax value is 2049,
+        /// then a two digit value of 50 will get converted to 1950 while a two digit
+        /// value of 49 will get converted to 2049.
         /// </summary>
         public virtual int ToFourDigitYear(int year)
         {
@@ -711,7 +712,7 @@ internal static long TimeToTicks(int hour, int minute, int second, int milliseco
 
         internal static int GetSystemTwoDigitYearSetting(CalendarId CalID, int defaultYearValue)
         {
-            int twoDigitYearMax = GlobalizationMode.UseNls ? CalendarData.NlsGetTwoDigitYearMax(CalID) : CalendarData.IcuGetTwoDigitYearMax();
+            int twoDigitYearMax = CalendarData.GetTwoDigitYearMax(CalID);
             return twoDigitYearMax >= 0 ? twoDigitYearMax : defaultYearValue;
         }
     }

src/libraries/System.Private.CoreLib/src/System/Globalization/CalendarData.Icu.cs

@@ -81,15 +81,6 @@ private bool IcuLoadCalendarDataFromSystem(string localeName, CalendarId calenda
             return result;
         }
 
-        internal static int IcuGetTwoDigitYearMax()
-        {
-            Debug.Assert(!GlobalizationMode.UseNls);
-
-            // There is no user override for this value on Linux or in ICU.
-            // So just return -1 to use the hard-coded defaults.
-            return -1;
-        }
-
         // Call native side to figure out which calendars are allowed
         internal static int IcuGetCalendars(string localeName, CalendarId[] calendars)
         {

src/libraries/System.Private.CoreLib/src/System/Globalization/CalendarData.Nls.cs

@@ -10,17 +10,6 @@ namespace System.Globalization
 {
     internal sealed partial class CalendarData
     {
-        // Get native two digit year max
-        internal static int NlsGetTwoDigitYearMax(CalendarId calendarId)
-        {
-            Debug.Assert(GlobalizationMode.UseNls);
-
-            return GlobalizationMode.Invariant ? Invariant.iTwoDigitYearMax :
-                    CallGetCalendarInfoEx(null, calendarId, CAL_ITWODIGITYEARMAX, out int twoDigitYearMax) ?
-                        twoDigitYearMax :
-                        -1;
-        }
-
         private static bool NlsSystemSupportsTaiwaneseCalendar()
         {
             Debug.Assert(!GlobalizationMode.Invariant);
@@ -34,7 +23,6 @@ private static bool NlsSystemSupportsTaiwaneseCalendar()
 
         private const uint CAL_RETURN_NUMBER = 0x20000000;
         private const uint CAL_SCALNAME = 0x00000002;
-        private const uint CAL_ITWODIGITYEARMAX = 0x00000030;
 
         private static bool CallGetCalendarInfoEx(string? localeName, CalendarId calendar, uint calType, out int data)
         {

src/libraries/System.Private.CoreLib/src/System/Globalization/CalendarData.Unix.cs

@@ -1,6 +1,8 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System.Diagnostics;
+
 namespace System.Globalization
 {
     internal sealed partial class CalendarData
@@ -12,5 +14,14 @@ private bool LoadCalendarDataFromSystemCore(string localeName, CalendarId calend
         internal static int GetCalendarsCore(string localeName, bool useUserOverride, CalendarId[] calendars) =>
             IcuGetCalendars(localeName, calendars);
 #pragma warning restore IDE0060
-     }
+
+        internal static int GetTwoDigitYearMax(CalendarId calendarId)
+        {
+            Debug.Assert(!GlobalizationMode.UseNls);
+
+            // There is no user override for this value on Linux or in ICU.
+            // So just return -1 to use the hard-coded defaults.
+            return GlobalizationMode.Invariant ? Invariant.iTwoDigitYearMax : -1;
+        }
+    }
 }

src/libraries/System.Private.CoreLib/src/System/Globalization/CalendarData.Windows.cs

@@ -23,6 +23,7 @@ internal sealed partial class CalendarData
         private const uint CAL_SSHORTESTDAYNAME7 = 0x00000037;
         private const uint CAL_SERASTRING = 0x00000004;
         private const uint CAL_SABBREVERASTRING = 0x00000039;
+        private const uint CAL_ITWODIGITYEARMAX = 0x00000030;
 
         private const uint ENUM_ALL_CALENDARS = 0xffffffff;
 
@@ -426,5 +427,16 @@ private static int NlsGetCalendars(string localeName, bool useUserOverride, Cale
             // Now we have a list of data, return the count
             return data.calendars.Count;
         }
+
+        // Get native two digit year max
+        internal static int GetTwoDigitYearMax(CalendarId calendarId)
+        {
+            Debug.Assert(GlobalizationMode.UseNls);
+
+            return GlobalizationMode.Invariant ? Invariant.iTwoDigitYearMax :
+                    CallGetCalendarInfoEx(null, calendarId, CAL_ITWODIGITYEARMAX, out int twoDigitYearMax) ?
+                        twoDigitYearMax :
+                        -1;
+        }
     }
 }

src/libraries/System.Private.CoreLib/src/System/Globalization/CalendarData.cs

@@ -39,8 +39,7 @@ internal sealed partial class CalendarData
         internal string[] saAbbrevMonthGenitiveNames = null!; // Genitive Abbrev Month Names (13)
         internal string[] saLeapYearMonthNames = null!; // Multiple strings for the month names in a leap year.
 
-        // Integers at end to make marshaller happier
-        internal int iTwoDigitYearMax = 2029; // Max 2 digit year (for Y2K bug data entry)
+        internal int iTwoDigitYearMax = 2049; // Max 2 digit year
         private int iCurrentEra;  // current era # (usually 1)
 
         // Use overrides?
@@ -66,7 +65,7 @@ private static CalendarData CreateInvariant()
             invariant.sNativeName = "Gregorian Calendar";  // Calendar Name
 
             // Year
-            invariant.iTwoDigitYearMax = 2029; // Max 2 digit year (for Y2K bug data entry)
+            invariant.iTwoDigitYearMax = 2049; // Max 2 digit year
             invariant.iCurrentEra = 1; // Current era #
 
             // Formats

src/libraries/System.Private.CoreLib/src/System/Globalization/EastAsianLunisolarCalendar.cs

@@ -646,15 +646,15 @@ public override bool IsLeapYear(int year, int era)
             return InternalIsLeapYear(year);
         }
 
-        private const int DefaultGregorianTwoDigitYearMax = 2029;
+        private const int DefaultGregorianTwoDigitYearMax = 2049;
 
         public override int TwoDigitYearMax
         {
             get
             {
                 if (_twoDigitYearMax == -1)
                 {
-                    _twoDigitYearMax = GetSystemTwoDigitYearSetting(BaseCalendarID, GetYear(new DateTime(DefaultGregorianTwoDigitYearMax, 1, 1)));
+                    _twoDigitYearMax = GetSystemTwoDigitYearSetting(ID, DefaultGregorianTwoDigitYearMax);
                 }
 
                 return _twoDigitYearMax;

src/libraries/System.Private.CoreLib/src/System/Globalization/GregorianCalendar.cs

@@ -406,7 +406,7 @@ internal override bool TryToDateTime(int year, int month, int day, int hour, int
             return DateTime.TryCreate(year, month, day, hour, minute, second, millisecond, out result);
         }
 
-        private const int DefaultTwoDigitYearMax = 2029;
+        private const int DefaultTwoDigitYearMax = 2049;
 
         public override int TwoDigitYearMax
         {

src/libraries/System.Private.CoreLib/src/System/Globalization/JulianCalendar.cs

@@ -54,7 +54,7 @@ public class JulianCalendar : Calendar
         public JulianCalendar()
         {
             // There is no system setting of TwoDigitYear max, so set the value here.
-            _twoDigitYearMax = 2029;
+            _twoDigitYearMax = 2049;
         }
 
         internal override CalendarId ID => CalendarId.JULIAN;