From 0970b610b1ab5aa75134f98c8f5957fe1d8bb9ed Mon Sep 17 00:00:00 2001
From: Diogo Rolo <d.rolo0@gmail.com>
Date: Wed, 20 Jul 2022 13:40:38 +0100
Subject: [PATCH] Fix null reference access when ContentType is null

---
 Octokit.Tests/Exceptions/ApiExceptionTests.cs | 11 +++++++++++
 Octokit/Exceptions/ApiException.cs            |  2 +-
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/Octokit.Tests/Exceptions/ApiExceptionTests.cs b/Octokit.Tests/Exceptions/ApiExceptionTests.cs
index bad38f72fe..7daa4aec38 100644
--- a/Octokit.Tests/Exceptions/ApiExceptionTests.cs
+++ b/Octokit.Tests/Exceptions/ApiExceptionTests.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.Linq;
 using System.Net;
 #if !NO_SERIALIZABLE
@@ -141,6 +142,16 @@ public void DoesNotThrowIfBodyIsNotDefined()
                 Assert.NotNull(stringRepresentation);
             }
 
+            [Fact]
+            public void DoesNotThrowIfContentTypeIsNotDefined()
+            {
+                var response = CreateResponse(HttpStatusCode.GatewayTimeout, null, new Dictionary<string, string>(), null);
+
+                var exception = new ApiException(response);
+                var stringRepresentation = exception.ToString();
+                Assert.NotNull(stringRepresentation);
+            }
+
             [Fact]
             public void DoesNotPrintImageContent()
             {
diff --git a/Octokit/Exceptions/ApiException.cs b/Octokit/Exceptions/ApiException.cs
index 4dd08d27e4..9c99713605 100644
--- a/Octokit/Exceptions/ApiException.cs
+++ b/Octokit/Exceptions/ApiException.cs
@@ -200,7 +200,7 @@ protected string HttpResponseBodySafe
         {
             get
             {
-                return HttpResponse != null
+                return HttpResponse?.ContentType != null
                        && !HttpResponse.ContentType.StartsWith("image/", StringComparison.OrdinalIgnoreCase)
                        && HttpResponse.Body is string
                     ? (string)HttpResponse.Body : string.Empty;