DirectoryMock.EnumerateDirectories does not throw exceptions until enumerated

[stogle]

The real Directory.EnumerateDirectories will immediately throw IO exceptions for missing directory/etc. (see FileSystemEnumerator.Windows.cs#L48-L50). The equivalent DirectoryMock.EnumerateDirectories will not throw these exceptions until you start to enumerate the result. The same may be true for other methods that return enumerations.

To resolve this, I think InMemoryStorage.EnumerateLocations needs to be split into two methods, something like:

public IEnumerable<IStorageLocation> EnumerateLocations(...)
{
    // check for missing directory/etc. and throw exceptions

    return EnumerateLocationsImpl(...)
}

private IEnumerable<IStorageLocation> EnumerateLocationsImpl(...)
{
    // existing implementation with yield return
}

The checking and throwing in the first method should happen during the initial call, while the code in the second method won't happen until the caller enumerates the result.

[vbreuss]

Thanks for reporting and the detailed analysis, @stogle. I will release a fix shortly!

[github-actions]

This is addressed in release v4.3.6.

[stogle]

@vbreuss Thank you for the incredibly fast response! This does solve the problem in the case where the directory does not exist, or the path points to a file rather than a directory. However, there is also the case where the directory cannot be accessed due to lack of permissions. In this scenario, RealFileSystem throws UnauthorizedAccessException immediately, but MockFileSystem still doesn't throw until the result is enumerated.

I think the solution here is just to move the code that does the parent access check from the private method to the public method. The private method can then accept IDisposable parentAccess as a parameter instead of bool requestParentAccess.

I do apologize for not mentioning this scenario in my initial report. I am not aware of any others.

[github-actions]

This is addressed in release v4.3.7.

[stogle]

Perfect. Thanks @vbreuss.