azrepos-cfg: only clear useHttpPath on Windows if no manager-core

Only clear the useHttpPath=true option on calls to unconfigure if the
"manager-core" option is not present and we're in the system config on a
Windows platform.

This would be the case for the bundled GCM Core in Git for Windows,
which we would break by removing this option.

Author: mjcheetham

src/shared/Microsoft.AzureRepos.Tests/AzureReposHostProviderTests.cs

@@ -5,6 +5,7 @@
 using System.Threading.Tasks;
 using Microsoft.Git.CredentialManager;
 using Microsoft.Git.CredentialManager.Authentication;
+using Microsoft.Git.CredentialManager.Tests;
 using Microsoft.Git.CredentialManager.Tests.Objects;
 using Moq;
 using Xunit;
@@ -14,6 +15,8 @@ namespace Microsoft.AzureRepos.Tests
 {
     public class AzureReposHostProviderTests
     {
+        private static readonly string HelperKey =
+            $"{Constants.GitConfiguration.Credential.SectionName}.{Constants.GitConfiguration.Credential.Helper}";
         private static readonly string AzDevUseHttpPathKey =
             $"{Constants.GitConfiguration.Credential.SectionName}.https://dev.azure.com.{Constants.GitConfiguration.Credential.UseHttpPath}";
 
@@ -222,7 +225,6 @@ public async Task AzureReposHostProvider_ConfigureAsync_UseHttpPathUnset_SetsUse
             Assert.Equal("true", actualValues[0]);
         }
 
-
         [Fact]
         public async Task AzureReposHostProvider_UnconfigureAsync_UseHttpPathSet_RemovesEntry()
         {
@@ -235,5 +237,48 @@ public async Task AzureReposHostProvider_UnconfigureAsync_UseHttpPathSet_Removes
 
             Assert.Empty(context.Git.GlobalConfiguration.Dictionary);
         }
+
+        [PlatformFact(Platforms.Windows)]
+        public async Task AzureReposHostProvider_UnconfigureAsync_System_Windows_UseHttpPathSetAndManagerCoreHelper_DoesNotRemoveEntry()
+        {
+            var context = new TestCommandContext();
+            var provider = new AzureReposHostProvider(context);
+
+            context.Git.SystemConfiguration.Dictionary[HelperKey] = new List<string> {"manager-core"};
+            context.Git.SystemConfiguration.Dictionary[AzDevUseHttpPathKey] = new List<string> {"true"};
+
+            await provider.UnconfigureAsync(ConfigurationTarget.System);
+
+            Assert.True(context.Git.SystemConfiguration.Dictionary.TryGetValue(AzDevUseHttpPathKey, out IList<string> actualValues));
+            Assert.Single(actualValues);
+            Assert.Equal("true", actualValues[0]);
+        }
+
+        [PlatformFact(Platforms.Windows)]
+        public async Task AzureReposHostProvider_UnconfigureAsync_System_Windows_UseHttpPathSetNoManagerCoreHelper_RemovesEntry()
+        {
+            var context = new TestCommandContext();
+            var provider = new AzureReposHostProvider(context);
+
+            context.Git.SystemConfiguration.Dictionary[AzDevUseHttpPathKey] = new List<string> {"true"};
+
+            await provider.UnconfigureAsync(ConfigurationTarget.System);
+
+            Assert.Empty(context.Git.SystemConfiguration.Dictionary);
+        }
+
+        [PlatformFact(Platforms.Windows)]
+        public async Task AzureReposHostProvider_UnconfigureAsync_User_Windows_UseHttpPathSetAndManagerCoreHelper_RemovesEntry()
+        {
+            var context = new TestCommandContext();
+            var provider = new AzureReposHostProvider(context);
+
+            context.Git.GlobalConfiguration.Dictionary[HelperKey] = new List<string> {"manager-core"};
+            context.Git.GlobalConfiguration.Dictionary[AzDevUseHttpPathKey] = new List<string> {"true"};
+
+            await provider.UnconfigureAsync(ConfigurationTarget.User);
+
+            Assert.False(context.Git.GlobalConfiguration.Dictionary.TryGetValue(AzDevUseHttpPathKey, out _));
+        }
     }
 }

src/shared/Microsoft.AzureRepos/AzureReposHostProvider.cs

@@ -2,6 +2,7 @@
 // Licensed under the MIT license.
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using System.Threading.Tasks;
 using Microsoft.Git.CredentialManager;
 using Microsoft.Git.CredentialManager.Authentication;
@@ -275,6 +276,7 @@ public Task ConfigureAsync(ConfigurationTarget target)
 
         public Task UnconfigureAsync(ConfigurationTarget target)
         {
+            string helperKey = $"{Constants.GitConfiguration.Credential.SectionName}.{Constants.GitConfiguration.Credential.Helper}";
             string useHttpPathKey = $"{KnownGitCfg.Credential.SectionName}.https://dev.azure.com.{KnownGitCfg.Credential.UseHttpPath}";
 
             _context.Trace.WriteLine("Clearing Git configuration 'credential.useHttpPath' for https://dev.azure.com...");
@@ -284,7 +286,14 @@ public Task UnconfigureAsync(ConfigurationTarget target)
                 : GitConfigurationLevel.Global;
 
             IGitConfiguration targetConfig = _context.Git.GetConfiguration(configurationLevel);
-            targetConfig.Unset(useHttpPathKey);
+
+            // On Windows, if there is a "manager-core" entry remaining in the system config then we must not clear
+            // the useHttpPath option otherwise this would break the bundled version of GCM Core in Git for Windows.
+            if (!PlatformUtils.IsWindows() || target != ConfigurationTarget.System ||
+                targetConfig.GetAll(helperKey).All(x => !string.Equals(x, "manager-core")))
+            {
+                targetConfig.Unset(useHttpPathKey);
+            }
 
             return Task.CompletedTask;
         }