Hey, thanks very much for this PR and proposed enhancement! It would excellent if we can include this in a future release.

It's always great to see some files being fully deleted! As it happens, these changes highlight another thing we can simplify, because it turns out that we can drop the config/netrc.go file entirely as it's not used anywhere. That will eliminate some duplicative code and another whole source code file.

We will want some updates to our shell tests as part of this PR, to make sure it has the intended effect. Right now there are a few tests in the t/t-credentials.sh test script which use either .netrc or _netrc, depending on the OS platform.

One option might be to run all of these tests nested inside a for loop, which iterates over just .netrc on Unix platforms but over .netrc and _netrc on Windows, and so runs each test twice on Windows.

I think that's probably a bit excessive, though; it's probably sufficient just to repeat the initial credentials from netrc test for this purpose with both possible file names.

(While we're at it, we can also make the condtition which checks the OS platform a little more consistent with our other tests by using if [ "$IS_WINDOWS" -eq 1 ], which is slightly more readable than what we have now, and also covers more POSIX environments on Windows.)

So this might look something like the following:

NETRCFILES=".netrc"
if [ "$IS_WINDOWS" -eq 1 ]; then
  NETRCFILES+=" _netrc"
fi

for netrcfile in $NETRCFILES; do
  begin_test "credentials from netrc ($netrcfile)"
  (
    set -e

    printf "machine localhost\nlogin netrcuser\npassword netrcpass\n" >"$HOME/$netrcfile"
    ...
  )
  end_test
done

begin_test "credentials from netrc with unknown keyword"
(
  set -e

  printf "machine localhost\nlogin netrcuser\nnot-a-key something\npassword netrcpass\n" >"$HOME/.netrc"
  ...
)
end_test

# ... and then also use "$HOME/.netrc" in the subsequent tests instead of "$NETRCFILE"

I've added two commits on top of yours in my windows-netrc branch and I see that our Windows CI job ran the t/t-credentials.sh script with my changes successfully, so I think these commits could be added to this PR, if you're willing to pull them into your branch. (Or if you prefer to issue me an invitation to push to your fork, I can do that instead.)

I tried to include some relevant details in the commit messages so we won't have to dig around in the Git history as much in the future if there are any concerns down the road.

Thanks again very much for tackling this issue and putting this PR together!

I've added two commits on top of yours in my windows-netrc branch and I see that our Windows CI job ran the t/t-credentials.sh script with my changes successfully, so I think these commits could be added to this PR, if you're willing to pull them into your branch. (Or if you prefer to issue me an invitation to push to your fork, I can do that instead.)

As you noted, I merged your suggestions (and also run an extra test on our system where the issue surfaced).