MDEV-20498 Assertion `table_share->tmp_table != NO_TMP_TABLE || m_lock_type == 1' failed upon REBUILD PARTITION.

Reorganise checks if it inserts rows from old partition into new that
wasn't opened for reading. So rows that don't belong there will produce an error.

Author: Alexey Botchkov

mysql-test/main/partition.result

@@ -2906,5 +2906,18 @@ Table	Op	Msg_type	Msg_text
 test.t1	check	status	OK
 DROP TABLE t1;
 #
+# MDEV-20498 Assertion `table_share->tmp_table != NO_TMP_TABLE || m_lock_type == 1' failed upon REBUILD PARTITION.
+#     ALTER TABLE REBUILD PARTITION crashed on misplaced rows.
+#
+CREATE TABLE mdev20498 (a INT) ENGINE=myisam PARTITION BY LIST (a)
+(PARTITION p0 VALUES IN (0), PARTITION p1 VALUES IN (1));
+INSERT INTO mdev20498 values (0), (0), (1), (1);
+FLUSH TABLES;
+CALL mtr.add_suppression("corrupted: row in wrong partition:");
+ALTER TABLE mdev20498 REBUILD PARTITION p0;
+ERROR HY000: Found a row in wrong partition (0 != 1) a:1
+ALTER TABLE mdev20498 REBUILD PARTITION p0, p1;
+DROP TABLE mdev20498;
+#
 # End of 10.6 tests
 #

mysql-test/main/partition.test

@@ -3115,6 +3115,32 @@ ALTER TABLE t1 DROP a, ADD a INT NOT NULL DEFAULT 0;
 CHECK TABLE t1;
 DROP TABLE t1;
 
+--echo #
+--echo # MDEV-20498 Assertion `table_share->tmp_table != NO_TMP_TABLE || m_lock_type == 1' failed upon REBUILD PARTITION.
+--echo #     ALTER TABLE REBUILD PARTITION crashed on misplaced rows.
+--echo #
+
+CREATE TABLE mdev20498 (a INT) ENGINE=myisam PARTITION BY LIST (a)
+      (PARTITION p0 VALUES IN (0), PARTITION p1 VALUES IN (1));
+INSERT INTO mdev20498 values (0), (0), (1), (1);
+FLUSH TABLES;
+
+let $datadir=`select @@datadir`;
+CALL mtr.add_suppression("corrupted: row in wrong partition:");
+
+move_file $datadir/test/mdev20498#P#p0.MYD $datadir/test//tmp.MYD;
+move_file $datadir/test/mdev20498#P#p1.MYD $datadir/test/mdev20498#P#p0.MYD;
+move_file $datadir/test/tmp.MYD $datadir/test/mdev20498#P#p1.MYD;
+
+move_file $datadir/test/mdev20498#P#p0.MYI $datadir/test/tmp.MYI;
+move_file $datadir/test/mdev20498#P#p1.MYI $datadir/test/mdev20498#P#p0.MYI;
+move_file $datadir/test/tmp.MYI $datadir/test/mdev20498#P#p1.MYI;
+
+--error ER_ROW_IN_WRONG_PARTITION
+ALTER TABLE mdev20498 REBUILD PARTITION p0;
+ALTER TABLE mdev20498 REBUILD PARTITION p0, p1;
+DROP TABLE mdev20498;
+
 --echo #
 --echo # End of 10.6 tests
 --echo #

sql/ha_partition.cc

@@ -2227,6 +2227,13 @@ int ha_partition::copy_partitions(ulonglong * const copied,
       }
       else
       {
+        if (m_new_file[new_part]->m_lock_type != F_WRLCK)
+        {
+          m_last_part= reorg_part;
+          m_err_rec= table->record[0];
+          result= HA_ERR_ROW_IN_WRONG_PARTITION;
+          goto error;
+        }
         /* Copy record to new handler */
         (*copied)++;
         DBUG_ASSERT(!m_new_file[new_part]->row_logging);
@@ -10326,11 +10333,12 @@ void ha_partition::print_error(int error, myf errflag)
   }
   else if (error == HA_ERR_ROW_IN_WRONG_PARTITION)
   {
-    /* Should only happen on DELETE or UPDATE! */
+    /* Should only happen on DELETE, UPDATE or REBUILD PARTITION! */
     DBUG_ASSERT(thd_sql_command(thd) == SQLCOM_DELETE ||
                 thd_sql_command(thd) == SQLCOM_DELETE_MULTI ||
                 thd_sql_command(thd) == SQLCOM_UPDATE ||
-                thd_sql_command(thd) == SQLCOM_UPDATE_MULTI);
+                thd_sql_command(thd) == SQLCOM_UPDATE_MULTI ||
+                thd_sql_command(thd) == SQLCOM_ALTER_TABLE);
     DBUG_ASSERT(m_err_rec);
     if (m_err_rec)
     {