Specify UriKind.Absolute

Be explicit and require the URI to be absolute.

Author: martincostello

src/AspNet.Security.OAuth.Automatic/AutomaticAuthenticationHandler.cs

@@ -56,7 +56,7 @@ protected override string BuildChallengeUrl([NotNull] AuthenticationProperties p
         var challengeUrl = base.BuildChallengeUrl(properties, redirectUri);
 
         // The redirect_uri parameter is not allowed by Automatic and MUST NOT be sent.
-        var challengeUri = new Uri(challengeUrl);
+        var challengeUri = new Uri(challengeUrl, UriKind.Absolute);
         var query = QueryHelpers.ParseQuery(challengeUri.Query);
 
         query.Remove("redirect_uri");

src/AspNet.Security.OAuth.VisualStudio/VisualStudioAuthenticationHandler.cs

@@ -92,7 +92,7 @@ protected override string BuildChallengeUrl([NotNull] AuthenticationProperties p
         var challengeUrl = base.BuildChallengeUrl(properties, redirectUri);
 
         // Visual Studio Online/Azure DevOps uses "Assertion" instead of "code"
-        var challengeUri = new Uri(challengeUrl);
+        var challengeUri = new Uri(challengeUrl, UriKind.Absolute);
         var query = QueryHelpers.ParseQuery(challengeUri.Query);
 
         query["response_type"] = "Assertion";