From 518869e249af65abbfda2dcb3d60c094b86f14cc Mon Sep 17 00:00:00 2001
From: Wraith <wraith2@gmail.com>
Date: Mon, 30 Jan 2023 21:24:22 +0000
Subject: [PATCH] Fix NullReferenceException in GetBytesAsync (#1906)

---
 .../Microsoft/Data/SqlClient/SqlDataReader.cs |  2 +-
 .../DataReaderTest/DataReaderStreamsTest.cs   | 32 +++++++++++++++++++
 2 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/src/Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/SqlClient/SqlDataReader.cs b/src/Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/SqlClient/SqlDataReader.cs
index 8d43d72685..965803f993 100644
--- a/src/Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/SqlClient/SqlDataReader.cs
+++ b/src/Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/SqlClient/SqlDataReader.cs
@@ -5285,7 +5285,7 @@ protected override void DisposeCore()
             {
                 TDisposable copy = _disposable;
                 _disposable = default;
-                copy.Dispose();
+                copy?.Dispose();
             }
         }
 
diff --git a/src/Microsoft.Data.SqlClient/tests/ManualTests/SQL/DataReaderTest/DataReaderStreamsTest.cs b/src/Microsoft.Data.SqlClient/tests/ManualTests/SQL/DataReaderTest/DataReaderStreamsTest.cs
index f008d6b2fa..3f16a3a138 100644
--- a/src/Microsoft.Data.SqlClient/tests/ManualTests/SQL/DataReaderTest/DataReaderStreamsTest.cs
+++ b/src/Microsoft.Data.SqlClient/tests/ManualTests/SQL/DataReaderTest/DataReaderStreamsTest.cs
@@ -9,6 +9,7 @@
 using System.Text;
 using System.Threading.Tasks;
 using System.Xml;
+using System.Xml.Linq;
 using Xunit;
 
 namespace Microsoft.Data.SqlClient.ManualTesting.Tests
@@ -471,6 +472,37 @@ public static void InvalidCastExceptionStream(CommandBehavior behavior, Accessor
             }
         }
 
+#if NETCOREAPP
+        [ConditionalFact(typeof(DataTestUtility),nameof(DataTestUtility.AreConnStringsSetup), nameof(DataTestUtility.IsNotAzureSynapse))]
+        public static async void ReadAsyncContentsCompletes()
+        {
+            string expectedXml = "<test>This is a test string</test>";
+            string query = $"SELECT CAST('{expectedXml}' AS NVARCHAR(MAX))";
+
+            string returnedXml = null;
+            using (SqlConnection connection = new SqlConnection(DataTestUtility.TCPConnectionString))
+            using (SqlCommand command = new SqlCommand(query, connection))
+            {
+                connection.Open();
+
+                await using (SqlDataReader reader = await command.ExecuteReaderAsync(CommandBehavior.SequentialAccess).ConfigureAwait(false))
+                {
+                    while (await reader.ReadAsync().ConfigureAwait(false))
+                    {
+                        using (TextReader textReader = reader.GetTextReader(0))
+                        using (XmlReader xmlReader = XmlReader.Create(textReader, new XmlReaderSettings() { Async = true }))
+                        {
+                            XDocument xdoc = await XDocument.LoadAsync(xmlReader, LoadOptions.None, default).ConfigureAwait(false);
+                            returnedXml = xdoc.ToString();
+                        }
+                    }
+                }
+            }
+
+            Assert.Equal(expectedXml, returnedXml, StringComparer.Ordinal);
+        }
+#endif
+
         private static async Task<SqlDataReader> ExecuteReader(SqlCommand command, CommandBehavior behavior, bool isExecuteAsync)
             => isExecuteAsync ? await command.ExecuteReaderAsync(behavior) : command.ExecuteReader(behavior);