From e1d4728d904e5e0768872713cbcdfa0483843922 Mon Sep 17 00:00:00 2001
From: Filip Staffa <filip.staffa@gmail.com>
Date: Wed, 1 Jul 2020 00:05:54 +0200
Subject: [PATCH] Fix HeaderSegmentCollection failing when header value has a
 trailing space (#23159)

Co-authored-by: Filip Staffa <git@filipstaffa.net>
---
 .../src/Internal/HeaderSegmentCollection.cs       |  5 +++++
 src/Http/Http/test/HeaderDictionaryTests.cs       | 15 ++++++++++++++-
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/src/Http/Http.Abstractions/src/Internal/HeaderSegmentCollection.cs b/src/Http/Http.Abstractions/src/Internal/HeaderSegmentCollection.cs
index b83bf4eeea..e06ae7b012 100644
--- a/src/Http/Http.Abstractions/src/Internal/HeaderSegmentCollection.cs
+++ b/src/Http/Http.Abstractions/src/Internal/HeaderSegmentCollection.cs
@@ -254,6 +254,11 @@ namespace Microsoft.AspNetCore.Http
                                 switch (attr)
                                 {
                                     case Attr.Delimiter:
+                                        if (ch == (char)0)
+                                        {
+                                            _valueEnd = _offset;
+                                            _trailingStart = _offset;
+                                        }
                                         _mode = Mode.Produce;
                                         break;
                                     case Attr.Quote:
diff --git a/src/Http/Http/test/HeaderDictionaryTests.cs b/src/Http/Http/test/HeaderDictionaryTests.cs
index 26113f53c0..e9cf32ebe3 100644
--- a/src/Http/Http/test/HeaderDictionaryTests.cs
+++ b/src/Http/Http/test/HeaderDictionaryTests.cs
@@ -103,5 +103,18 @@ namespace Microsoft.AspNetCore.Http
             Assert.Throws<InvalidOperationException>(() => headers.Remove(new KeyValuePair<string, StringValues>("header1", "value1")));
             Assert.Throws<InvalidOperationException>(() => headers.Remove("header1"));
         }
+
+        [Fact]
+        public void GetCommaSeparatedValues_WorksForUnquotedHeaderValuesEndingWithSpace()
+        {
+            var headers = new HeaderDictionary
+            {
+                { "Via", "value " },
+            };
+
+            var result = headers.GetCommaSeparatedValues("Via");
+
+            Assert.Equal(new[]{"value "}, result);
+        }
     }
-}
\ No newline at end of file
+}