From: Egor Bogatov <egorbo@gmail.com>
Date: Thu, 21 Sep 2017 05:57:35 +0000 (+0300)
Subject: [corlib] Fix 44255: Inconsistent results in the serialization of TimeZoneInfo.  ... 
X-Git-Url: http://wien.tomnetworks.com/gitweb/?p=mono.git;a=commitdiff_plain;h=ccb1921b7b7c5aeed57744d1f21f7fa3ce82066b

[corlib] Fix 44255: Inconsistent results in the serialization of TimeZoneInfo.  (#5576)
---

diff --git a/mcs/class/corlib/System/TimeZoneInfo.Serialization.cs b/mcs/class/corlib/System/TimeZoneInfo.Serialization.cs
index b272a20f00c..b78b5536b8e 100644
--- a/mcs/class/corlib/System/TimeZoneInfo.Serialization.cs
+++ b/mcs/class/corlib/System/TimeZoneInfo.Serialization.cs
@@ -42,12 +42,14 @@ namespace System
 			var displayName = DeserializeString (ref input);
 			var standardName = DeserializeString (ref input);
 			var daylightName = DeserializeString (ref input);
-			var rules = new List<TimeZoneInfo.AdjustmentRule> ();
+			List<TimeZoneInfo.AdjustmentRule> rules = null;
 			while (input [0] != ';') {
+				if (rules == null)
+					rules = new List<TimeZoneInfo.AdjustmentRule> ();
 				rules.Add (DeserializeAdjustmentRule (ref input));
 			}
 			var offsetSpan = TimeSpan.FromMinutes (offset);
-			return TimeZoneInfo.CreateCustomTimeZone (tzId, offsetSpan, displayName, standardName, daylightName, rules.ToArray ());
+			return TimeZoneInfo.CreateCustomTimeZone (tzId, offsetSpan, displayName, standardName, daylightName, rules?.ToArray ());
 		}
 
 		public string ToSerializedString ()
diff --git a/mcs/class/corlib/System/TimeZoneInfo.cs b/mcs/class/corlib/System/TimeZoneInfo.cs
index 1c5cdd3ae82..25d9e9a39be 100644
--- a/mcs/class/corlib/System/TimeZoneInfo.cs
+++ b/mcs/class/corlib/System/TimeZoneInfo.cs
@@ -624,7 +624,7 @@ namespace System
 			else
 				ParseRegTzi(adjustmentRules, 1, 9999, reg_tzi);
 
-			return CreateCustomTimeZone (id, baseUtcOffset, display_name, standard_name, daylight_name, ValidateRules (adjustmentRules).ToArray ());
+			return CreateCustomTimeZone (id, baseUtcOffset, display_name, standard_name, daylight_name, ValidateRules (adjustmentRules));
 		}
 
 		private static void ParseRegTzi (List<AdjustmentRule> adjustmentRules, int start_year, int end_year, byte [] buffer)
@@ -1231,8 +1231,11 @@ namespace System
 			return new DateTime (year, transition.Month, day) + transition.TimeOfDay.TimeOfDay;
 		}
 
-		static List<AdjustmentRule> ValidateRules (List<AdjustmentRule> adjustmentRules)
+		static AdjustmentRule[] ValidateRules (List<AdjustmentRule> adjustmentRules)
 		{
+			if (adjustmentRules == null || adjustmentRules.Count == 0)
+				return null;
+
 			AdjustmentRule prev = null;
 			foreach (AdjustmentRule current in adjustmentRules.ToArray ()) {
 				if (prev != null && prev.DateEnd > current.DateStart) {
@@ -1240,7 +1243,7 @@ namespace System
 				}
 				prev = current;
 			}
-			return adjustmentRules;
+			return adjustmentRules.ToArray ();
 		}
 
 #if LIBC || MONOTOUCH
@@ -1404,13 +1407,13 @@ namespace System
 				}
 				tz = CreateCustomTimeZone (id, baseUtcOffset, id, standardDisplayName);
 			} else {
-				tz = CreateCustomTimeZone (id, baseUtcOffset, id, standardDisplayName, daylightDisplayName, ValidateRules (adjustmentRules).ToArray ());
+				tz = CreateCustomTimeZone (id, baseUtcOffset, id, standardDisplayName, daylightDisplayName, ValidateRules (adjustmentRules));
 			}
 
 			if (storeTransition && transitions.Count > 0) {
 				tz.transitions = transitions;
-				tz.supportsDaylightSavingTime = true;
 			}
+			tz.supportsDaylightSavingTime = adjustmentRules.Count > 0;
 
 			return tz;
 		}
diff --git a/mcs/class/corlib/Test/System/TimeZoneInfo.SerializationTest.cs b/mcs/class/corlib/Test/System/TimeZoneInfo.SerializationTest.cs
index f4d0cfa1e8c..b53a8d4496a 100644
--- a/mcs/class/corlib/Test/System/TimeZoneInfo.SerializationTest.cs
+++ b/mcs/class/corlib/Test/System/TimeZoneInfo.SerializationTest.cs
@@ -1,5 +1,6 @@
 using System;
 using System.IO;
+using System.Linq;
 using NUnit.Framework;
 
 namespace MonoTests.System
@@ -24,6 +25,20 @@ namespace MonoTests.System
 			Assert.AreEqual (0, utc.GetAdjustmentRules ().Length);
 		}
 
+		[Test] // Bug-44255
+		public void SystemTimeZoneSerializationTests ()
+		{
+			foreach (var tmz in TimeZoneInfo.GetSystemTimeZones ())
+			{
+				var tmzClone = TimeZoneInfo.FromSerializedString (tmz.ToSerializedString ());
+				Assert.AreEqual (tmz, tmzClone);
+				Assert.AreEqual (tmz.DisplayName, tmzClone.DisplayName);
+				Assert.AreEqual (tmz.StandardName, tmzClone.StandardName);
+				Assert.AreEqual (tmz.SupportsDaylightSavingTime, tmzClone.SupportsDaylightSavingTime);
+				Assert.AreEqual (tmz.DaylightName, tmzClone.DaylightName);
+			}
+		}
+
 		[Test]
 		public void SerializeCustomUtcZoneWithOddNaming ()
 		{