Fix #160

When first value of select is empty, decoder assumes it is ok packet (like eof)
for various cases
the fix is to check the state of the query, if this is the middle of query
treat it as query processing and not ok packet

mysql-async/src/main/java/com/github/jasync/sql/db/mysql/codec/MySQLFrameDecoder.kt

@@ -54,7 +54,7 @@ class MySQLFrameDecoder(val charset: Charset, private val connectionId: String)
     private var processedParams = 0L
     var totalColumns = 0L
     var processedColumns = 0L
-    private var expectedColDefMsgCount = 0L;
+    private var expectedColDefMsgCount = 0L
 
     private var hasReadColumnsCount = false
 
@@ -110,6 +110,7 @@ class MySQLFrameDecoder(val charset: Charset, private val connectionId: String)
     }
 
     private fun handleCommonFlow(messageType: Byte, slice: ByteBuf, out: MutableList<Any>) {
+        logger.trace { "got message type $messageType" }
         val decoder = when (messageType.toInt()) {
             ServerMessage.Error -> {
                 this.clear()
@@ -144,15 +145,17 @@ class MySQLFrameDecoder(val charset: Charset, private val connectionId: String)
                     } else {
                         // workaround for MemSQL ColDef messages being exactly 19 bytes, all ZEROS.
                         slice.resetReaderIndex()
-                        expectedColDefMsgCount--;
+                        expectedColDefMsgCount--
                         this.columnDecoder
                     }
                 } else {
-                    if (this.isPreparedStatementExecuteRows) {
-                        null
-                    } else {
-                        this.clear()
-                        this.okDecoder
+                    when {
+                        this.isPreparedStatementExecuteRows -> null
+                        this.isInQuery -> null
+                        else -> {
+                            this.clear()
+                            this.okDecoder
+                        }
                     }
                 }
             }
@@ -188,7 +191,7 @@ class MySQLFrameDecoder(val charset: Charset, private val connectionId: String)
                     this.hasReadColumnsCount = true
                     this.totalColumns = result.columnsCount.toLong()
                     this.totalParams = result.paramsCount.toLong()
-                    this.expectedColDefMsgCount = this.totalColumns +  this.totalParams;
+                    this.expectedColDefMsgCount = this.totalColumns +  this.totalParams
                 }
                 is ParamAndColumnProcessingFinishedMessage -> {
                     this.clear()

mysql-async/src/test/java/com/github/jasync/sql/db/mysql/QueryMoreSpec.kt

@@ -0,0 +1,20 @@
+package com.github.jasync.sql.db.mysql
+
+import org.junit.Test
+
+class QueryMoreSpec : ConnectionHelper() {
+
+
+
+
+    @Test
+    fun `"connection" should   "be able to select with empty value" `() {
+        withConnection { connection ->
+            executeQuery(connection, "select '' as x,'1' as y ")
+        }
+
+    }
+
+}
+
+

versions.gradle

@@ -7,9 +7,9 @@ ext.sl4j_version='1.7.25'
 ext.joda_version='2.9.7'
 ext.joda_convert_version='1.8.1'
 ext.netty_version='4.1.34.Final'
-ext.kotlin_logging_version='1.6.23'
+ext.kotlin_logging_version='1.7.6'
 
-// test dependencines
+// test dependencies
 
 ext.assertj_version='3.11.1'
 ext.mockk_version='1.9'