Repository.Clone() : Cross host redirect not allowed

Windows Server 2008 R2 SP2 ASP.NET C# libgit2sharp 0.21.0.176

From CLI this git operation succeeds without issue :

git clone https://www.github.com/{org-name}/{repo-name}.git

The expected local repo is created in folder \{org-name}\{repo-name}

But when ASP.NET C# app attempts programmatically equivalent operation LibGit2Sharp.Repository.Clone() of same GitHub URI an exception is thrown : “Cross host redirect not allowed”

In the Visual Studio debugger I can see that the URI is being formed and passed to Repository.Clone() as expected – so this isn’t an issue with a malformed URI.

C# code :

var cloneOptions = new CloneOptions { 
  BranchName = "master",
  Checkout = true,
  CredentialsProvider = (url, user, cred) =>    
  new UsernamePasswordCredentials { Username = {username}, Password = {password}}
};

string cloneResult;
try {
  cloneResult = Repository.Clone(
  "https://www.github.com/{my-org}/{my-repo}.git",
  "c:\github\{my-org}\{my-repo}",
  cloneOptions);            
} catch (LibGit2SharpException e) {}

Repository.Clone() throws a run-time exception :

Cross host redirect not allowed : at LibGit2Sharp.Core.Ensure.HandleError(Int32 result) at LibGit2Sharp.Core.Proxy.git_clone(String url, String workdir, GitCloneOptions& opts) at LibGit2Sharp.Repository.Clone(String sourceUrl, String workdirPath, CloneOptions options)

Apparently here is where libgit2sharp throws the exception on line 188 : https://github.com/libgit2/libgit2/blob/master/src/netops.c

[carlosmn]

GitHub canonicalizes its URLs as https://github.com/{user}/{repo}(.git). You however keep using https://www.github.com/ as a URL, which is a hostname which GitHub itself never produces, and it will redirect away from the www regardless of whether you claim to be a Git or a browser.

As such, it counts as a cross-host redirect, since github.com and www.github.com are not the same hostname. If you remove that extraneous www. prefix, it should work.

[ethomson]

@john-grandy-opentable I trust that things worked out in the end - I’m closing this, it’s quite stale now.