From 05737645433d78040a9218bb27dac052718fdadf Mon Sep 17 00:00:00 2001
From: Senthil <mohan.senthilkumar@gmail.com>
Date: Thu, 25 Oct 2018 03:28:33 +0100
Subject: [PATCH] fixes#330-Yield validation err when an invalid security req
 key found

---
 .../Services/OpenApiReferenceResolver.cs            | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/src/Microsoft.OpenApi.Readers/Services/OpenApiReferenceResolver.cs b/src/Microsoft.OpenApi.Readers/Services/OpenApiReferenceResolver.cs
index d11f06770..60a9bbfb6 100644
--- a/src/Microsoft.OpenApi.Readers/Services/OpenApiReferenceResolver.cs
+++ b/src/Microsoft.OpenApi.Readers/Services/OpenApiReferenceResolver.cs
@@ -108,11 +108,14 @@ public override void Visit(OpenApiSecurityRequirement securityRequirement)
             {
                 ResolveObject(scheme, (resolvedScheme) =>
                 {
-                    // If scheme was unresolved
-                    // copy Scopes and remove old unresolved scheme
-                    var scopes = securityRequirement[scheme];
-                    securityRequirement.Remove(scheme);
-                    securityRequirement.Add(resolvedScheme, scopes);
+                    if (resolvedScheme != null)
+                    {
+                        // If scheme was unresolved
+                        // copy Scopes and remove old unresolved scheme
+                        var scopes = securityRequirement[scheme];
+                        securityRequirement.Remove(scheme);
+                        securityRequirement.Add(resolvedScheme, scopes);
+                    }
                 });
             }
         }