Index.Remove with directory/pattern does not always work

The problem could be related to the commit operation but I'm not sure. If instead of repo.Index.Remove("*") you pass the filename, it is correctly removed from the Index.

Also if you commit the file using the console git client the * version starts working correctly.

For reproduction please see the following unit test:

using LibGit2Sharp;
using NUnit.Framework;
using System;
using System.IO;
using System.Linq;

namespace Tests
{
    public class LibGitTest
    {
        [Test]
        public void TestRemove()
        {
            var tempPath = Path.Combine(Path.GetTempPath(), "LibGitTest");

            if (Directory.Exists(tempPath))
            {
                DeleteDirectory(tempPath);
            }
            Directory.CreateDirectory(tempPath);

            using (var repo = new Repository(Repository.Init(tempPath)))
            {
                File.WriteAllText(Path.Combine(tempPath, "a.txt"), "some text");

                repo.Stage("*.*");
                var signature = repo.Config.BuildSignature(DateTimeOffset.Now);
                repo.Commit("Initial commit", signature, signature);

                repo.Index.Remove("*");
                // repo.Index.Remove("a.txt"); // uncomment this line to make the test pass

                var status = repo.RetrieveStatus();
                Assert.Contains("a.txt", status.Removed.Select(entry => entry.FilePath).ToArray());
            }
        }

        private static void DeleteDirectory(string tempPath)
        {
            // Some files in the .git folder are readonly, I'm not sure whether that's normal, but we need to reset the flag in order to successfully delete the directory
            Directory.EnumerateFiles(Path.Combine(tempPath), "*", SearchOption.AllDirectories)
                .ForEach(f => File.SetAttributes(f, File.GetAttributes(f) & ~FileAttributes.ReadOnly));

            Directory.Delete(tempPath, recursive: true);
        }
    }
}

首先运行 TestRemove 单元测试，并检查 repo.Index.Remove("*") 的行为与直接删除 "a.txt" 相比有何不同。跟踪索引删除以及随后 RetrieveStatus() 的结果，包括 commit 操作是否会影响模式匹配。完成的标准是：现有测试在使用通配符删除时通过，并且直接使用文件名时的行为仍然正确。