Get commit SHA from branch is wrong

[michael-kokorin]

If I use the following code:

var commitSha = client.Repository.GetBranch(
                GetSetting(GitHubItSettingKeys.RepositoryOwner),
                GetSetting(GitHubItSettingKeys.RepositoryName),
                branchId)
                .Result.Commit.Sha;

            var sources = client.Repository.Content.GetArchive(
                GetSetting(GitHubItSettingKeys.RepositoryOwner),
                GetSetting(GitHubItSettingKeys.RepositoryName),
                ArchiveFormat.Zipball,
                commitSha)
                .Result;

and branchId is different from master then I always get sources from master branch.
This behavior started from version 0.16 and till now. Version 0.15 gets correct result

[ryangribble]

Looks like that function inadvertently passes String.Empty rather than the reference parameter into the next call in the chain

https://github.com/octokit/octokit.net/blob/master/Octokit/Clients/RepositoryContentsClient.cs#L241

In the meantime you should be able to use the overload that takes an additional TimeSpan argument (pass in 60 minutes if you want the same behaviour as the overload you are wanting to use), to work around the issue.

[shiftkey]

@ryangribble nice spot - yep, that's a bug

[shiftkey]

Added the easy-fix label as I think this is good for someone new to contribute. I'd also like to see a unit test for this to verify that we're passing through the right value.

[shiftkey]

Fixed by #1113