From 84f8bfb070df6a06c0749a385184a0393f906c9a Mon Sep 17 00:00:00 2001
From: Jiri Pechanec <jpechane@redhat.com>
Date: Wed, 27 Jun 2018 09:14:59 +0200
Subject: [PATCH] DBZ-767 Column should not be renamed when name is not changed

---
 .../listener/AlterTableParserListener.java    |  4 ++-
 .../connector/mysql/MySqlDdlParserTest.java   | 25 +++++++++++++++++++
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/debezium-connector-mysql/src/main/java/io/debezium/connector/mysql/antlr/listener/AlterTableParserListener.java b/debezium-connector-mysql/src/main/java/io/debezium/connector/mysql/antlr/listener/AlterTableParserListener.java
index 344a0aed7..881bff6b8 100644
--- a/debezium-connector-mysql/src/main/java/io/debezium/connector/mysql/antlr/listener/AlterTableParserListener.java
+++ b/debezium-connector-mysql/src/main/java/io/debezium/connector/mysql/antlr/listener/AlterTableParserListener.java
@@ -161,7 +161,9 @@ public void exitAlterByChangeColumn(MySqlParser.AlterByChangeColumnContext ctx)
             Column column = columnDefinitionListener.getColumn();
             tableEditor.addColumn(column);
             String newColumnName = parser.parseName(ctx.newColumn);
-            tableEditor.renameColumn(column.name(), newColumnName);
+            if (newColumnName != null && !column.name().equals(newColumnName)) {
+                tableEditor.renameColumn(column.name(), newColumnName);
+            }
 
             if (ctx.FIRST() != null) {
                 tableEditor.reorderColumn(newColumnName, null);
diff --git a/debezium-connector-mysql/src/test/java/io/debezium/connector/mysql/MySqlDdlParserTest.java b/debezium-connector-mysql/src/test/java/io/debezium/connector/mysql/MySqlDdlParserTest.java
index 87c540dcf..0cac3f11e 100644
--- a/debezium-connector-mysql/src/test/java/io/debezium/connector/mysql/MySqlDdlParserTest.java
+++ b/debezium-connector-mysql/src/test/java/io/debezium/connector/mysql/MySqlDdlParserTest.java
@@ -1514,6 +1514,31 @@ public void parsePartitionWithEngine() {
         assertThat(tables.forTable(new TableId(null, null, "flat_view_request_log"))).isNotNull();
     }
 
+    @Test
+    @FixFor("DBZ-767")
+    public void shouldParseChangeColumnAndKeepName() {
+        final String create =
+                "CREATE TABLE test (" +
+                "  id INT NOT NULL, myvalue ENUM('Foo','Bar','Baz') NOT NULL DEFAULT 'Foo'," +
+                "  PRIMARY KEY (`id`)" +
+                ");";
+        final String alter =
+                "ALTER TABLE test " +
+                "  CHANGE myvalue myvalue INT;";
+
+        parser.parse(create, tables);
+        assertThat(tables.size()).isEqualTo(1);
+        Table table = tables.forTable(new TableId(null, null, "test"));
+        assertThat(table).isNotNull();
+        assertThat(table.columns().size()).isEqualTo(2);
+        parser.parse(alter, tables);
+        table = tables.forTable(new TableId(null, null, "test"));
+        assertThat(table.columns().size()).isEqualTo(2);
+        final Column col = table.columns().get(1);
+        assertThat(col.name()).isEqualTo("myvalue");
+        assertThat(col.typeName()).isEqualTo("INT");
+    }
+
     @Test
     public void parseDefaultValue() {
         String ddl = "CREATE TABLE tmp (id INT NOT NULL, " +