MDEV-14943 Alter table ORDER BY bug

Problem was that if copy_data_between_tables() didn't do proper
clean up in case of failures:
- copy object was not properly freed
- end_bulk_insert() was not called
- mysql_trans_prepare_alter_copy_data() set THD->transaction.on to
  false which was not properly restored

The last part caused a crash in Aria as Aria depends on that THD
is correct.

Other things:
- Reset info->switched_transactional after usage (safety)
- Reset bulk_insert_single_undo (safety)

2 files changed, 33 insertions, 0 deletions

diff --git a/mysql-test/suite/maria/alter.result b/mysql-test/suite/maria/alter.result
index 1a7daf5a1ee..c63688dddd6 100644
--- a/mysql-test/suite/maria/alter.result
+++ b/mysql-test/suite/maria/alter.result
@@ -31,3 +31,19 @@ pk	i
 8	88
 9	99
 DROP TABLE t1;
+CREATE TABLE t1 (f INT) ENGINE=Aria transactional=1;
+SHOW CREATE TABLE t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `f` int(11) DEFAULT NULL
+) ENGINE=Aria DEFAULT CHARSET=latin1 PAGE_CHECKSUM=1 TRANSACTIONAL=1
+INSERT INTO t1 VALUES (1),(2);
+ALTER TABLE t1 ORDER BY unknown_column;
+ERROR 42S22: Unknown column 'unknown_column' in 'order clause'
+SHOW CREATE TABLE t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `f` int(11) DEFAULT NULL
+) ENGINE=Aria DEFAULT CHARSET=latin1 PAGE_CHECKSUM=1 TRANSACTIONAL=1
+CREATE TABLE t2 SELECT * FROM t1;
+DROP TABLE t1, t2;
diff --git a/mysql-test/suite/maria/alter.test b/mysql-test/suite/maria/alter.test
index abca4865688..09672cdfa3b 100644
--- a/mysql-test/suite/maria/alter.test
+++ b/mysql-test/suite/maria/alter.test
@@ -25,3 +25,20 @@ INSERT INTO t1 VALUES (2,0),(3,33),(4,0),(5,55),(6,66),(7,0),(8,88),(9,99);
 ALTER TABLE t1 ENABLE KEYS;
 SELECT * FROM t1 WHERE i = 0 OR pk BETWEEN 6 AND 10;
 DROP TABLE t1;
+
+#
+# MDEV-14943
+# Assertion `block->type == PAGECACHE_EMPTY_PAGE || block->type == type ||
+# type == PAGECACHE_LSN_PAGE || type == PAGECACHE_READ_UNKNOWN_PAGE ||
+# block->type == PAGECACHE_READ_UNKNOWN_PAGE' failed in pagecache_read upon
+# CREATE ... SELECT from Aria table
+#
+
+CREATE TABLE t1 (f INT) ENGINE=Aria transactional=1;
+SHOW CREATE TABLE t1;
+INSERT INTO t1 VALUES (1),(2);
+--error ER_BAD_FIELD_ERROR
+ALTER TABLE t1 ORDER BY unknown_column;
+SHOW CREATE TABLE t1;
+CREATE TABLE t2 SELECT * FROM t1;
+DROP TABLE t1, t2;