[2.1.6] Fix | Default UTF8 collation conflict (#1739)

src/Microsoft.Data.SqlClient/netfx/src/Microsoft/Data/SqlClient/TdsParser.cs

@@ -3054,19 +3054,13 @@ private bool TryProcessEnvChange(int tokenLength, TdsParserStateObject stateObj,
                             _defaultCollation = env.newCollation;
                             _defaultLCID = env.newCollation.LCID;
 
-                            int newCodePage = GetCodePage(env.newCollation, stateObj);
-
                             if ((env.newCollation.info & TdsEnums.UTF8_IN_TDSCOLLATION) == TdsEnums.UTF8_IN_TDSCOLLATION)
                             { // UTF8 collation
                                 _defaultEncoding = Encoding.UTF8;
-
-                                if (newCodePage != _defaultCodePage)
-                                {
-                                    _defaultCodePage = newCodePage;
-                                }
                             }
                             else
                             {
+                                int newCodePage = GetCodePage(env.newCollation, stateObj);
 
                                 if (newCodePage != _defaultCodePage)
                                 {

src/Microsoft.Data.SqlClient/tests/ManualTests/DataCommon/DataTestUtility.cs

@@ -358,16 +358,23 @@ public static string GetUniqueName(string prefix, bool withBracket = true)
             return uniqueName;
         }
 
-        // SQL Server supports long names (up to 128 characters), add extra info for troubleshooting
-        public static string GetUniqueNameForSqlServer(string prefix)
+        /// <summary>
+        /// Uses environment values `UserName` and `MachineName` in addition to the specified `prefix` and current date
+        /// to generate a unique name to use in Sql Server; 
+        /// SQL Server supports long names (up to 128 characters), add extra info for troubleshooting.
+        /// </summary>
+        /// <param name="prefix">Add the prefix to the generate string.</param>
+        /// <param name="withBracket">Database name must be pass with brackets by default.</param>
+        /// <returns>Unique name by considering the Sql Server naming rules.</returns>
+        public static string GetUniqueNameForSqlServer(string prefix, bool withBracket = true)
         {
             string extendedPrefix = string.Format(
-                "{0}_{1}@{2}",
+                "{0}_{1}_{2}@{3}",
                 prefix,
                 Environment.UserName,
                 Environment.MachineName,
                 DateTime.Now.ToString("yyyy_MM_dd", CultureInfo.InvariantCulture));
-            string name = GetUniqueName(extendedPrefix);
+            string name = GetUniqueName(extendedPrefix, withBracket);
             if (name.Length > 128)
             {
                 throw new ArgumentOutOfRangeException("the name is too long - SQL Server names are limited to 128");
@@ -399,6 +406,30 @@ public static void DropStoredProcedure(SqlConnection sqlConnection, string spNam
             }
         }
 
+        private static void ResurrectConnection(SqlConnection sqlConnection, int counter = 2)
+        {
+            if (sqlConnection.State == ConnectionState.Closed)
+            {
+                sqlConnection.Open();
+            }
+            while (counter-- > 0 && sqlConnection.State == ConnectionState.Connecting)
+            {
+                Thread.Sleep(80);
+            }
+        }
+
+        /// <summary>
+        /// Drops specified database on provided connection.
+        /// </summary>
+        /// <param name="sqlConnection">Open connection to be used.</param>
+        /// <param name="dbName">Database name without brackets.</param>
+        public static void DropDatabase(SqlConnection sqlConnection, string dbName)
+        {
+            ResurrectConnection(sqlConnection);
+            using SqlCommand cmd = new(string.Format("IF (EXISTS(SELECT 1 FROM sys.databases WHERE name = '{0}')) \nBEGIN \n ALTER DATABASE [{0}] SET SINGLE_USER WITH ROLLBACK IMMEDIATE \n DROP DATABASE [{0}] \nEND", dbName), sqlConnection);
+            cmd.ExecuteNonQuery();
+        }
+
         public static bool IsLocalDBInstalled() => SupportsLocalDb;
 
         public static bool IsIntegratedSecuritySetup() => SupportsIntegratedSecurity;

src/Microsoft.Data.SqlClient/tests/ManualTests/SQL/Utf8SupportTest/Utf8SupportTest.cs

@@ -2,6 +2,8 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+using System.Text;
+using System.Threading;
 using Xunit;
 
 namespace Microsoft.Data.SqlClient.ManualTesting.Tests
@@ -29,6 +31,76 @@ public static void CheckSupportUtf8ConnectionProperty()
             }
         }
 
-        // TODO: Write tests using UTF8 collations
+        // skip creating database on Azure
+        [ConditionalFact(typeof(DataTestUtility), nameof(DataTestUtility.AreConnStringsSetup), nameof(DataTestUtility.IsNotAzureServer), nameof(DataTestUtility.IsNotAzureSynapse))]
+        public static void UTF8databaseTest()
+        {
+            const string letters = @"!\#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~\u007f€\u0081‚ƒ„…†‡ˆ‰Š‹Œ\u008dŽ\u008f\u0090‘’“”•–—˜™š›œ\u009džŸ ¡¢£¤¥¦§¨©ª«¬­®¯°±²³´µ¶·¸¹º»¼½¾¿ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùúûüýþÿ";
+            string dbName = DataTestUtility.GetUniqueNameForSqlServer("UTF8databaseTest", false);
+            string tblName = "Table1";
+
+            SqlConnectionStringBuilder builder = new(DataTestUtility.TCPConnectionString);
+            builder.InitialCatalog = "master";
+
+            using SqlConnection cn = new(builder.ConnectionString);
+            cn.Open();
+
+            try
+            {
+                PrepareDatabaseUTF8(cn, dbName, tblName, letters);
+
+                builder.InitialCatalog = dbName;
+                using SqlConnection cnnTest = new(builder.ConnectionString);
+                // creating a databse is a time consumer action and could be retried.
+                int count = 3;
+                while(count-- > 0)
+                {
+                    try
+                    {
+                        cnnTest.Open();
+                        break;
+                    }
+                    catch
+                    {
+                        if (count == 0) throw;
+
+                        Thread.Sleep(200);
+                    }
+                }
+
+                using SqlCommand cmd = cnnTest.CreateCommand();
+                cmd.CommandText = $"SELECT * FROM {tblName}";
+
+                using SqlDataReader reader = cmd.ExecuteReader();
+
+                Assert.True(reader.Read(), "The test table should have a row!");
+                object[] data = new object[1];
+                reader.GetSqlValues(data);
+                Assert.Equal(letters, data[0].ToString());
+                reader.Close();
+                cnnTest.Close();
+            }
+            finally
+            {
+                DataTestUtility.DropDatabase(cn, dbName);
+            }
+        }
+
+        private static void PrepareDatabaseUTF8(SqlConnection cnn, string dbName, string tblName, string letters)
+        {
+            StringBuilder sb = new();
+
+            using SqlCommand cmd = cnn.CreateCommand();
+
+            cmd.CommandText = $"CREATE DATABASE [{dbName}] COLLATE Latin1_General_100_CI_AS_SC_UTF8;";
+            cmd.ExecuteNonQuery();
+
+            sb.AppendLine($"CREATE TABLE [{dbName}].dbo.[{tblName}] (col VARCHAR(7633) COLLATE Latin1_General_100_CI_AS_SC);");
+            sb.AppendLine($"INSERT INTO [{dbName}].dbo.[{tblName}] VALUES (@letters);");
+
+            cmd.Parameters.Add(new SqlParameter("letters", letters));
+            cmd.CommandText = sb.ToString();
+            cmd.ExecuteNonQuery();
+        }
     }
 }