InMemoryDirectoryInfo does not work as expected

[antonKrouglov]

Microsoft.Extensions.FileSystemGlobbing

Steps to reproduce (file C:\pagefile.sys exists):

            var d = new InMemoryDirectoryInfo(@"C:\", new[] { @"pagefile.sys" });
            var l = d.EnumerateFileSystemInfos().ToList(); //returns empty list

Thus using

public static PatternMatchingResult Match(this Matcher matcher, string rootDir, IEnumerable<string> files)

does not work as well - the result is always empty.

[Eilon]

pagefile.sys is normally a hidden+system file. I'm guessing it's not included in globbing for that reason. I believe that similarly files that start with . are ignored due to Unix naming conventions.

[Eilon]

For example, here are the files in the root of my C: drive:

A  SH   I            C:\hiberfil.sys
A  SH                C:\pagefile.sys
A  SH                C:\swapfile.sys

[antonKrouglov]

Eilion, I may miss something but how in-memory FS correllate to on-disk FS?
It does not matter what is on disk. In my case I have a 5+ million files list offloaded from production server.
I need it to filter it locally with glob patterns.

If you look at code you will see that EnumerateFileSystemInfos calls IsRootDirectory:

        private bool IsRootDirectory(string rootDir, string filePath)
        {
            if (!filePath.StartsWith(rootDir, StringComparison.Ordinal) ||
                filePath.IndexOf(Path.DirectorySeparatorChar, rootDir.Length) != rootDir.Length)
            {
                return false;
            }

            return true;
        }

It seems that it alsways false as filePath.IndexOf(Path.DirectorySeparatorChar, rootDir.Length) != rootDir.Length is always the same.

[Eilon]

Oh sorry I didn't realize you are just creating "made up" files.

[xied75]

BTW InMemoryDirectoryInfo is not under any test at all.

[albertodenatale]

@antonKrouglov @Eilon correct me if I am wrong, tried to run a test and might be that the issue occurs on path normalization, when the InMemoryDirectoryInfo constructor prepends the file names with the executing assembly directory path?

// normalize

foreach (var file in files)
{
    fileList.Add(Path.GetFullPath(file.Replace(Path.AltDirectorySeparatorChar, Path.DirectorySeparatorChar)));
}

Path.GetFullPath is prepending the file with the executing assembly directory path.

The same does not happen for the root path as it is already root directory

FullName = Path.GetFullPath(rootDir.Replace(Path.AltDirectorySeparatorChar, Path.DirectorySeparatorChar));

Hence they will not be enumerated in EnumerateFileSystemInfos as they will not look like belonging to rootDir (behavior consistent with what happen in DirectoryInfoWrapper where by default SearchOption.TopDirectoryOnly is set)?

[maryamariyan]

Related to dotnet/extensions#1272

UPDATE:
More info on this bug here