Extend RepositoryOptions to accept path to alternate System and Global config files

LibGit2Sharp.Tests/ConfigurationFixture.cs

@@ -14,13 +14,6 @@ private static void AssertValueInLocalConfigFile(string repoPath, string regex)
             AssertValueInConfigFile(configFilePath, regex);
         }
 
-        private static void AssertValueInConfigFile(string configFilePath, string regex)
-        {
-            var text = File.ReadAllText(configFilePath);
-            var r = new Regex(regex, RegexOptions.Multiline).Match(text);
-            Assert.True(r.Success, text);
-        }
-
         private static string RetrieveGlobalConfigLocation()
         {
             string[] variables = { "HOME", "USERPROFILE", };

LibGit2Sharp.Tests/RepositoryOptionsFixture.cs

@@ -1,5 +1,6 @@
 using System;
 using System.IO;
+using System.Text;
 using LibGit2Sharp.Tests.TestHelpers;
 using Xunit;
 
@@ -101,16 +102,6 @@ public void OpeningABareRepoWithoutProvidingBothWorkDirAndIndexThrows()
             Assert.Throws<ArgumentException>(() => repo = new Repository(BareTestRepoPath, new RepositoryOptions { WorkingDirectoryPath = newWorkdir }));
         }
 
-        [Fact]
-        public void OpeningARepoWithAnEmptyRepositoryOptionsThrows()
-        {
-            var options = new RepositoryOptions();
-            Repository repo;
-
-            Assert.Throws<ArgumentException>(() => repo = new Repository(BareTestRepoPath, options));
-            Assert.Throws<ArgumentException>(() => repo = new Repository(StandardTestRepoPath, options));
-        }
-
         [Fact]
         public void CanSneakAdditionalCommitsIntoAStandardRepoWithoutAlteringTheWorkdirOrTheIndex()
         {
@@ -150,5 +141,38 @@ private string MeanwhileInAnotherDimensionAnEvilMastermindIsAtWork(string workin
                 return sneakyRepo.Commit("Tadaaaa!", DummySignature, DummySignature).Sha;
             }
         }
+
+        [Fact]
+        public void CanProvideDifferentConfigurationFilesToARepository()
+        {
+            string globalLocation = Path.Combine(newWorkdir, "my-global-config");
+            string systemLocation = Path.Combine(newWorkdir, "my-system-config");
+
+            const string name = "Adam 'aroben' Roben";
+            const string email = "adam@github.com";
+
+            StringBuilder sb = new StringBuilder()
+                .AppendLine("[user]")
+                .AppendFormat("name = {0}{1}", name, Environment.NewLine)
+                .AppendFormat("email = {0}{1}", email, Environment.NewLine);
+
+            File.WriteAllText(globalLocation, sb.ToString());
+
+            var options = new RepositoryOptions {
+                GlobalConfigurationLocation = globalLocation,
+                SystemConfigurationLocation = systemLocation,
+            };
+
+            using (var repo = new Repository(BareTestRepoPath, options))
+            {
+                Assert.True(repo.Config.HasGlobalConfig);
+                Assert.Equal(name, repo.Config.Get<string>("user", "name", null));
+                Assert.Equal(email, repo.Config.Get<string>("user", "email", null));
+
+                repo.Config.Set("help.link", "https://twitter.com/xpaulbettsx/status/205761932626636800", ConfigurationLevel.System);
+            }
+
+            AssertValueInConfigFile(systemLocation, "xpaulbettsx");
+        }
     }
 }

LibGit2Sharp.Tests/TestHelpers/BaseFixture.cs

@@ -1,6 +1,8 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
+using System.Text.RegularExpressions;
+using Xunit;
 
 namespace LibGit2Sharp.Tests.TestHelpers
 {
@@ -94,5 +96,12 @@ protected void InconclusiveIf(Func<bool> predicate, string message)
 
             throw new SkipException(message);
         }
+
+        protected static void AssertValueInConfigFile(string configFilePath, string regex)
+        {
+            var text = File.ReadAllText(configFilePath);
+            var r = new Regex(regex, RegexOptions.Multiline).Match(text);
+            Assert.True(r.Success, text);
+        }
     }
 }

LibGit2Sharp/Configuration.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Globalization;
+using System.IO;
 using LibGit2Sharp.Core;
 using LibGit2Sharp.Core.Handles;
 
@@ -20,21 +21,56 @@ public class Configuration : IDisposable
         private ConfigurationSafeHandle globalHandle;
         private ConfigurationSafeHandle localHandle;
 
-        internal Configuration(Repository repository)
+        internal Configuration(Repository repository, string globalConfigurationFileLocation, string systemConfigurationFileLocation)
         {
             this.repository = repository;
 
-            globalConfigPath = ConvertPath(NativeMethods.git_config_find_global);
-            systemConfigPath = ConvertPath(NativeMethods.git_config_find_system);
+            globalConfigPath = globalConfigurationFileLocation ?? ConvertPath(NativeMethods.git_config_find_global);
+            systemConfigPath = systemConfigurationFileLocation ?? ConvertPath(NativeMethods.git_config_find_system);
 
             Init();
         }
 
+        private void Init()
+        {
+            if (repository != null)
+            {
+                Ensure.Success(NativeMethods.git_config_new(out localHandle));
+
+                string repoConfigLocation = Path.Combine(repository.Info.Path, "config");
+                Ensure.Success(NativeMethods.git_config_add_file_ondisk(localHandle, repoConfigLocation, 3));
+
+                if (globalConfigPath != null)
+                {
+                    Ensure.Success(NativeMethods.git_config_add_file_ondisk(localHandle, globalConfigPath, 2));
+                }
+
+                if (systemConfigPath != null)
+                {
+                    Ensure.Success(NativeMethods.git_config_add_file_ondisk(localHandle, systemConfigPath, 1));
+                }
+
+                NativeMethods.git_repository_set_config(repository.Handle, localHandle);
+            }
+
+            if (globalConfigPath != null)
+            {
+                Ensure.Success(NativeMethods.git_config_open_ondisk(out globalHandle, globalConfigPath));
+            }
+
+            if (systemConfigPath != null)
+            {
+                Ensure.Success(NativeMethods.git_config_open_ondisk(out systemHandle, systemConfigPath));
+            }
+        }
+
         /// <summary>
         ///   Access configuration values without a repository. Generally you want to access configuration via an instance of <see cref = "Repository" /> instead.
         /// </summary>
-        public Configuration()
-            : this(null)
+        /// <param name="globalConfigurationFileLocation">Path to a Global configuration file. If null, the default path for a global configuration file will be probed.</param>
+        /// <param name="systemConfigurationFileLocation">Path to a System configuration file. If null, the default path for a system configuration file will be probed.</param>
+        public Configuration(string globalConfigurationFileLocation = null, string systemConfigurationFileLocation = null)
+            : this(null, globalConfigurationFileLocation, systemConfigurationFileLocation)
         {
         }
 
@@ -246,24 +282,6 @@ public T Get<T>(string[] keyParts, T defaultValue)
             return Get(string.Join(".", keyParts), defaultValue);
         }
 
-        private void Init()
-        {
-            if (repository != null)
-            {
-                Ensure.Success(NativeMethods.git_repository_config(out localHandle, repository.Handle));
-            }
-
-            if (globalConfigPath != null)
-            {
-                Ensure.Success(NativeMethods.git_config_open_ondisk(out globalHandle, globalConfigPath));
-            }
-
-            if (systemConfigPath != null)
-            {
-                Ensure.Success(NativeMethods.git_config_open_ondisk(out systemHandle, systemConfigPath));
-            }
-        }
-
         private void Save()
         {
             Dispose(true);

LibGit2Sharp/Core/NativeMethods.cs

@@ -181,6 +181,15 @@ public static extern int git_config_get_string(
             ConfigurationSafeHandle cfg,
             [MarshalAs(UnmanagedType.CustomMarshaler, MarshalTypeRef = typeof(Utf8Marshaler))] string name);
 
+        [DllImport(libgit2)]
+        public static extern int git_config_add_file_ondisk(
+            ConfigurationSafeHandle cfg,
+            [MarshalAs(UnmanagedType.CustomMarshaler, MarshalTypeRef = typeof(FilePathMarshaler))] FilePath path,
+            int priority);
+
+        [DllImport(libgit2)]
+        public static extern int git_config_new(out ConfigurationSafeHandle cfg);
+
         [DllImport(libgit2)]
         public static extern int git_config_open_global(out ConfigurationSafeHandle cfg);
 
@@ -547,6 +556,11 @@ public static extern int git_repository_open(
         [return: MarshalAs(UnmanagedType.CustomMarshaler, MarshalTypeRef = typeof(FilePathMarshaler))]
         public static extern FilePath git_repository_path(RepositorySafeHandle repository);
 
+        [DllImport(libgit2)]
+        public static extern void git_repository_set_config(
+            RepositorySafeHandle repository,
+            ConfigurationSafeHandle index);
+
         [DllImport(libgit2)]
         public static extern void git_repository_set_index(
             RepositorySafeHandle repository,

LibGit2Sharp/Repository.cs

@@ -51,16 +51,14 @@ public Repository(string path, RepositoryOptions options = null)
 
             Func<Index> indexBuilder = () => new Index(this);
 
+            string configurationGlobalFilePath = null;
+            string configurationSystemFilePath = null;
+
             if (options != null)
             {
                 bool isWorkDirNull = string.IsNullOrEmpty(options.WorkingDirectoryPath);
                 bool isIndexNull = string.IsNullOrEmpty(options.IndexPath);
 
-                if (isWorkDirNull && isIndexNull)
-                {
-                    throw new ArgumentException(string.Format(CultureInfo.InvariantCulture, "At least one member of the {0} instance has to be provided.", typeof(RepositoryOptions).Name));
-                }
-
                 if (isBare && (isWorkDirNull ^ isIndexNull))
                 {
                     throw new ArgumentException("When overriding the opening of a bare repository, both RepositoryOptions.WorkingDirectoryPath an RepositoryOptions.IndexPath have to be provided.");
@@ -77,6 +75,9 @@ public Repository(string path, RepositoryOptions options = null)
                 {
                     Ensure.Success(NativeMethods.git_repository_set_workdir(handle, options.WorkingDirectoryPath));
                 }
+
+                configurationGlobalFilePath = options.GlobalConfigurationLocation;
+                configurationSystemFilePath = options.SystemConfigurationLocation;
             }
 
             if (!isBare)
@@ -89,7 +90,7 @@ public Repository(string path, RepositoryOptions options = null)
             branches = new BranchCollection(this);
             tags = new TagCollection(this);
             info = new Lazy<RepositoryInformation>(() => new RepositoryInformation(this, isBare));
-            config = new Lazy<Configuration>(() => RegisterForCleanup(new Configuration(this)));
+            config = new Lazy<Configuration>(() => RegisterForCleanup(new Configuration(this, configurationGlobalFilePath, configurationSystemFilePath)));
             remotes = new Lazy<RemoteCollection>(() => new RemoteCollection(this));
             odb = new Lazy<ObjectDatabase>(() => new ObjectDatabase(this));
             diff = new Diff(this);

LibGit2Sharp/RepositoryOptions.cs

@@ -25,5 +25,23 @@ public class RepositoryOptions
         ///   </para>
         /// </summary>
         public string IndexPath { get; set; }
+
+        /// <summary>
+        ///   Overrides the probed location of the Global configuration file of a repository.
+        ///   <para>
+        ///     The path has either to lead to an existing valid configuration file,
+        ///     or to a non existent configuration file which will be eventually created.
+        ///   </para>
+        /// </summary>
+        public string GlobalConfigurationLocation { get; set; }
+
+        /// <summary>
+        ///   Overrides the probed location of the System configuration file of a repository.
+        ///   <para>
+        ///     The path has to lead to an existing valid configuration file,
+        ///     or to a non existent configuration file which will be eventually created.
+        ///   </para>
+        /// </summary>
+        public string SystemConfigurationLocation { get; set; }
     }
 }