Re: [PATCH 1/2] config: check if config path is a file before parsing it

> I'm mildly negative on this approach for two reasons:
>
>   1. It requires doing an _extra_ check anywhere we want to care about
>      this. So if we care about file/directory confusion, we're going to
>      sprinkle these is_not_file() checks all over the code base.
>
>      I think we're much better to just do the thing we want to do (like
>      open the file), and deal with the error results. I'm on the fence
>      on whether we want to care about the fopen behavior on Linux here
>      (where reading a directory essentially behaves like an empty file,
>      because the first read() gives an error and we don't distinguish
>      between error and EOF).

> But if we do, I think we'd either want to:
>
>        a. actually check ferror() after getting EOF and report the read
>           error. That catches EISDIR, along with any other unexpected
>           errors.
>
>        b. use an fopen wrapper that checks fstat(fileno(fh)) after the
>           open, and turns fopen(some_dir) into an error.

>   2. It doesn't address the root problem for git_config_from_file(),
>      which is that it is quiet when fopen fails, even if the reason is
>      something interesting besides ENOENT. The caller can't check errno
>      because it doesn't know if fopen() failed, or if the config
>      callback returned an error.
>
>      There's an attempt to protect the call to git_config_from_file() by
>      checking access(), but that breaks down when access() and fopen()
>      have two different results (which is exactly what happens on
>      Windows in this case).
>
> -Peff