lfs.dir does not raise an error for not existing path on Windows

[moteus]

lfs.dir with not existing path raise error on *nix but not on Windows.
I think error path not found/file not found shold be considered not as error but just as empty resultset.
At least it should be same on all platforms.

[mpeterv]

Confirmed on Win10/VS2015, it returns an empty iterator. I think that current behaviour on other platforms (raising an error) is preferable.

[moteus]

I vote it should raise error if there some real error e.g. access denied. But if path does not exists it shuld returns empty iterator.

[mpeterv]

IMO if a directory you are trying to iterate over doesn't exist it's a real error, too, and it shouldn't be silently ignored. Let's see if there are any more opinions.

[Tieske]

I vote for consitent behaviour across platforms, so thow an error if it doesn't exist

[hishamhm]

I think it should throw an error if the path does not exist; at least this is what I would expect to happen in any filesystem library. Returning an empty iterator makes it indistiguishable from an empty directory.

[n1tehawk]

The key problem here is that the dir_iter_factory() doesn't really access the directory for Win32 (and thus also performs no checking), and leaves it up to the actual iterator function (dir_iter()) to enumerate directory entries using the Windows FindFirst/FindNext paradigm.

To properly raise an error on invalid paths, the function should verify that the parameter really points to a directory. I've successfully implemented some proof-of-concept code in n1tehawk@9f70724.

Regards, NiteHawk

[sonoro1234]

Any updates on this?

Another place where errors can happen is in calling the iterator function:
When there is a fail in win32 it returns nil, error making it imposible to distinguish from end of directory. (for f in just breaks)
In Linux there is no check of errno and just returns nil (even worse than win32)

My proposal would be to return false, errno on both platforms (as done in luapower/fs) so we can detect it as

for f,err in lsf.dir(path) do
    if not f then
       print("error",err)
       break
    end
    print("item is",f)
end

[sonoro1234]

See #132 (comment)