finagle-mysql: Update client charsets to be compatible with MySQL 8

**Problem**

Our MySQL client is incompatible with MySQL 8. This change is to support the key
incompatibility of:

  - **Character Sets:**
     MySQL 8.0 improved support for UTF8 character sets and changed the default
     from utf8mb3 to utf8mb4. With MySQL’s improved support, finagle-mysql has
     to expand the supported character sets.

**Solution/Result**

These changes make it so that all of the finagle-mysql tests pass with a locally
running MySQL 8 server.

Differential Revision: https://phabricator.twitter.biz/D590996

CHANGELOG.rst

@@ -20,6 +20,9 @@ Bug Fixes
 
 * finagle-core: Fix wraparound bug in `Ring.weight`, as reported by @nvartolomei ``PHAB_ID=D575958``
 
+* finagle-mysql: Update the UTF8 character set to cover those added in MySQL 8.
+  ``PHAB_ID=D590996``
+
 * finagle-thriftmux: Fixed a bug where connections were not established eagerly in ThriftMux
   MethodBuilder even when eager connections was enabled. ``PHAB_ID=D589592``
 
@@ -97,7 +100,6 @@ Bug Fixes
   `java.lang.UnsupportedOperationException: tail of empty stream` when a `c.t.f.s.RetryPolicy`
   is converted to a String for showing. ``PHAB_ID=D582199``
 
-
 20.10.0
 -------
 

finagle-mysql/src/main/scala/com/twitter/finagle/mysql/MysqlCharset.scala

@@ -30,10 +30,20 @@ object MysqlCharset {
   private[this] val Latin1Set = Set(5, 8, 15, 31, 47, 48, 49, 94)
 
   /**
+   * With MySQL 5.7:
    * "SELECT id,collation_name FROM information_schema.collations
-   * WHERE collation_name LIKE '%utf8' ORDER BY id"
+   * WHERE collation_name LIKE 'utf8%' ORDER BY id;"
    */
-  private[this] val Utf8Set = Set(192 to 254: _*) + 33 + 45 + 46 + 83
+  private[this] val Utf8MySql57Set = Set(192 to 254: _*) + 33 + 45 + 46 + 83
+
+  /**
+   * With MySQL 8.0:
+   * "SELECT id,collation_name FROM information_schema.collations
+   * WHERE collation_name LIKE 'utf8%' ORDER BY id;"
+   */
+  private[this] val Utf8MySql8OnlySet = Set(255 to 315: _*) + 76
+
+  private[this] val Utf8MySql8Set = Utf8MySql57Set ++ Utf8MySql8OnlySet
 
   /**
    * @see https://dev.mysql.com/doc/refman/5.7/en/charset-unicode-sets.html
@@ -50,9 +60,9 @@ object MysqlCharset {
    */
   val Binary: Short = 63.toShort
 
-  private[this] val CompatibleSet = Latin1Set ++ Utf8Set + Binary
+  private[this] val CompatibleSet = Latin1Set ++ Utf8MySql8Set + Binary
   def isCompatible(code: Short): Boolean = CompatibleSet(code)
-  def isUtf8(code: Short): Boolean = Utf8Set(code)
+  def isUtf8(code: Short): Boolean = Utf8MySql8Set(code)
   def isLatin1(code: Short): Boolean = Latin1Set(code)
   def isBinary(code: Short): Boolean = code == Binary
 }

finagle-mysql/src/main/scala/com/twitter/finagle/mysql/Request.scala

@@ -12,10 +12,11 @@ object Command {
   val COM_INIT_DB: Byte = 0x02.toByte // mysql_select_db
   val COM_QUERY: Byte = 0x03.toByte // mysql_real_query
   val COM_FIELD_LIST: Byte = 0x04.toByte // mysql_list_fields
-  val COM_CREATE_DB: Byte = 0x05.toByte // mysql_create_db (deperacted)
+  val COM_CREATE_DB: Byte = 0x05.toByte // mysql_create_db (deprecated)
   val COM_DROP_DB: Byte = 0x06.toByte // mysql_drop_db (deprecated)
   val COM_REFRESH: Byte = 0x07.toByte // mysql_refresh
-  val COM_SHUTDOWN: Byte = 0x08.toByte // mysql_shutdown
+  val COM_SHUTDOWN: Byte =
+    0x08.toByte // mysql_shutdown (deprecated as of 5.7, removal planned for 8 at some point; use SHUTDOWN in com_query instead).
   val COM_STATISTICS: Byte = 0x09.toByte // mysql_stat
   val COM_PROCESS_INFO: Byte = 0x0a.toByte // mysql_list_processes
   val COM_CONNECT: Byte = 0x0b.toByte // internal thread state

finagle-mysql/src/test/scala/com/twitter/finagle/mysql/integration/AbortedClientTest.scala

@@ -29,7 +29,7 @@ class AbortedClientTest extends FunSuite with IntegrationClient {
 
   for (c <- client) {
     test("MySql connections are closed cleanly, so MySql doesn't count them as aborted.") {
-      val abortedClientQuery = "SHOW GLOBAL STATUS LIKE '%Aborted_clients%'"
+      val abortedClientQuery = "SHOW GLOBAL STATUS LIKE 'Aborted_clients'"
       val initialAbortedValue: String =
         await(c.select(abortedClientQuery)(row => row.stringOrNull("Value"))).head
 

finagle-mysql/src/test/scala/com/twitter/finagle/mysql/integration/PreparedStatementTest.scala

@@ -101,6 +101,13 @@ class PreparedStatementTest extends FunSuite with IntegrationClient with BeforeA
   }
 
   test("insert BigDecimal with too much precision") {
+    // Depending on how the server is configured, this test may fail.
+    // With the following configurations (which happen to be MySQL's defaults) this test will pass:
+    // +-----------------------------------------------------------------------------------------------------------------------+
+    // | @@sql_mode                                                                                                            |
+    // +-----------------------------------------------------------------------------------------------------------------------+
+    // | ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_ENGINE_SUBSTITUTION |
+    // +-----------------------------------------------------------------------------------------------------------------------+
     intercept[ServerError] {
       // this number has more total digits than allowed, 5
       insertBigDecimal(Some(BigDecimal("100000")))