`Proxy.git_remote_connect()` hides exceptions

[YuKitsune]

I've noticed when calling Repository.ListRemoteReferences with a URL that doesn't point to a valid git repo, I get a fairly unhelpful error:

LibGit2Sharp.LibGit2SharpException: this remote has never connected
 at LibGit2Sharp.Core.Ensure.HandleError(Int32 result)
 at LibGit2Sharp.Core.Proxy.git_remote_ls(Repository repository, RemoteHandle remote)
 at LibGit2Sharp.Repository.ListRemoteReferences(String url, CredentialsHandler credentialsProvider)
 at LibGit2Sharp.Repository.ListRemoteReferences(String url)
 at LibGit2SharpScratchpad.Program.Main(String[] args)

I did some digging and noticed in Repository.ListRemoteReferences(string, CredentialsHandler), there is a call to git_remote_connect, then git_remote_ls. In git_remote_connect, if an exception is thrown (E.g: from the call to Ensure.ZeroResult(res)), it's caught and then ignored:

libgit2sharp/LibGit2Sharp/Core/Proxy.cs

Lines 2163 to 2176 in 6329bea

	public static unsafe void git_remote_connect(RemoteHandle remote, GitDirection direction, ref GitRemoteCallbacks remoteCallbacks, ref GitProxyOptions proxyOptions)
	{
	GitStrArrayManaged customHeaders = new GitStrArrayManaged();
	try
	{
	int res = NativeMethods.git_remote_connect(remote, direction, ref remoteCallbacks, ref proxyOptions, ref customHeaders.Array);
	Ensure.ZeroResult(res);
	}
	catch (Exception)
	{
	customHeaders.Dispose();
	}
	}

It looks like this was introduced in this commit: 6bc517f

Because this doesn't re-throw the exception, git_remote_ls gets given a null transport, and thus throws the this remote has never connected error.

I would've expected this to re-throw the exception after disposing of the custom headers.

Seems like an easy fix and I'm happy to send through a PR, just wondering if this was intentional or a legitimate bug.

[ethomson]

Yes, this looks like an error!

[YuKitsune]

Thanks for checking @ethomson
I've raised a PR: #1913