From 537fc4b60d0783dc260b4b26b64d1fd03db52cc8 Mon Sep 17 00:00:00 2001
From: Steve Pfister <steveisok@users.noreply.github.com>
Date: Thu, 11 Jul 2019 17:45:03 -0400
Subject: [PATCH] [ios] Ensure Local TimeZone Id is Set For TimeZoneInfo.Local 
 (#15667)

* Fixes https://github.com/mono/mono/issues/14839

The local timezone name was not known and defaulted to "Local".
This change adds an sdk function that returns the local name.
---
 mcs/class/corlib/System/TimeZoneInfo.MonoTouch.cs |  7 +++++--
 mcs/class/corlib/Test/System/TimeZoneInfoTest.cs  |  6 +++---
 sdks/ios/runtime/runtime.m                        | 16 ++++++++++++++++
 3 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/mcs/class/corlib/System/TimeZoneInfo.MonoTouch.cs b/mcs/class/corlib/System/TimeZoneInfo.MonoTouch.cs
index ba161b3f2e2..49b682b8a9b 100644
--- a/mcs/class/corlib/System/TimeZoneInfo.MonoTouch.cs
+++ b/mcs/class/corlib/System/TimeZoneInfo.MonoTouch.cs
@@ -44,10 +44,13 @@ namespace System {
 
 	public partial class TimeZoneInfo {
 
+		[DllImport ("__Internal")]
+		extern static string xamarin_timezone_get_local_name ();
+
 		static TimeZoneInfo CreateLocal ()
 		{
 			using (Stream stream = GetMonoTouchData (null)) {
-				return BuildFromStream ("Local", stream);
+				return BuildFromStream (xamarin_timezone_get_local_name (), stream);
 			}
 		}
 
@@ -68,7 +71,7 @@ namespace System {
 				}
 			}
 		}
-		
+
 		[DllImport ("__Internal")]
 		extern static IntPtr xamarin_timezone_get_names (ref int count);
 
diff --git a/mcs/class/corlib/Test/System/TimeZoneInfoTest.cs b/mcs/class/corlib/Test/System/TimeZoneInfoTest.cs
index 9f7340d3d15..9f14e72e712 100644
--- a/mcs/class/corlib/Test/System/TimeZoneInfoTest.cs
+++ b/mcs/class/corlib/Test/System/TimeZoneInfoTest.cs
@@ -121,6 +121,7 @@ namespace MonoTests.System
 			[Test] // Covers #24958
 			public void LocalId ()
 			{
+#if !MONOTOUCH && !XAMMAC
 				byte[] buf = new byte [512];
 
 				var path = "/etc/localtime";
@@ -131,10 +132,9 @@ namespace MonoTests.System
 				} catch (DllNotFoundException e) {
 					return;
 				}
-#if !MONOTOUCH && !XAMMAC
-				// this assumption is incorrect for the TimeZoneInfo.MonoTouch.cs implementation (iOS, tvOS, watchOS and XamMac Modern)
-				Assert.IsTrue (TimeZoneInfo.Local.Id != "Local", "Local timezone id should not be \"Local\"");
 #endif
+				
+				Assert.IsTrue (TimeZoneInfo.Local.Id != "Local", "Local timezone id should not be \"Local\"");
 			}
 		}
 
diff --git a/sdks/ios/runtime/runtime.m b/sdks/ios/runtime/runtime.m
index 16770da5da5..76c7377745f 100644
--- a/sdks/ios/runtime/runtime.m
+++ b/sdks/ios/runtime/runtime.m
@@ -337,6 +337,10 @@ mono_ios_runtime_init (void)
 //
 // ICALLS used by the mobile profile of mscorlib
 //
+// NOTE: The timezone functions are duplicated in XI, so if you're going to modify here, you have to 
+// modify there. 
+//
+// See in XI runtime/xamarin-support.m
 
 void*
 xamarin_timezone_get_data (const char *name, int *size)
@@ -355,6 +359,18 @@ xamarin_timezone_get_data (const char *name, int *size)
 	return result;
 }
 
+//
+// Returns the geopolitical region ID of the local timezone.
+
+const char *
+xamarin_timezone_get_local_name ()
+{
+	NSTimeZone *tz = nil;
+	tz = [NSTimeZone localTimeZone];
+	NSString *name = [tz name];
+	return strdup ([name UTF8String]);
+}
+
 char**
 xamarin_timezone_get_names (int *count)
 {
-- 
2.11.4.GIT