From 3259a2c9f60911e59d2c037eadb8a8bf38e1c7b6 Mon Sep 17 00:00:00 2001
From: Brennan <brecon@microsoft.com>
Date: Fri, 7 Jun 2019 15:32:08 -0700
Subject: [PATCH] Prefer File.Move for DataProtection key creation + Fallback
 (#10990)

---
 .../src/Repositories/FileSystemXmlRepository.cs     | 13 +++++++++++--
 .../Authentication/test/SecureDataFormatTests.cs    |  3 +--
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/src/DataProtection/DataProtection/src/Repositories/FileSystemXmlRepository.cs b/src/DataProtection/DataProtection/src/Repositories/FileSystemXmlRepository.cs
index 9eef2e2f18..19e11b6ac9 100644
--- a/src/DataProtection/DataProtection/src/Repositories/FileSystemXmlRepository.cs
+++ b/src/DataProtection/DataProtection/src/Repositories/FileSystemXmlRepository.cs
@@ -143,8 +143,17 @@ namespace Microsoft.AspNetCore.DataProtection.Repositories
                 // Renames are atomic operations on the file systems we support.
                 _logger.WritingDataToFile(finalFilename);
 
-                // Use File.Copy because File.Move on NFS shares has issues in .NET Core 2.0
-                File.Copy(tempFilename, finalFilename);
+                try
+                {
+                    // Prefer the atomic move operation to avoid multi-process startup issues
+                    File.Move(tempFilename, finalFilename);
+                }
+                catch (IOException)
+                {
+                    // Use File.Copy because File.Move on NFS shares has issues in .NET Core 2.0
+                    // See https://github.com/aspnet/AspNetCore/issues/2941 for more context
+                    File.Copy(tempFilename, finalFilename);
+                }
             }
             finally
             {
diff --git a/src/Security/Authentication/test/SecureDataFormatTests.cs b/src/Security/Authentication/test/SecureDataFormatTests.cs
index 9ff1c26728..a30da3b91b 100644
--- a/src/Security/Authentication/test/SecureDataFormatTests.cs
+++ b/src/Security/Authentication/test/SecureDataFormatTests.cs
@@ -48,8 +48,7 @@ namespace Microsoft.AspNetCore.Authentication.DataHandler
             Assert.Equal(input, result);
         }
 
-        [ConditionalFact]
-        [SkipOnHelix("https://github.com/aspnet/AspNetCore-Internal/issues/1974")]
+        [Fact]
         public void UnprotectWithDifferentPurposeFails()
         {
             var provider = ServiceProvider.GetRequiredService<IDataProtectionProvider>();