--source include/have_innodb.inc
--source include/have_log_bin.inc
--source include/not_embedded.inc

--echo #
--echo # MDEV-41636: a failed sync of ddl_recovery.log after the engine change makes
--echo # DROP TABLE / ALTER TABLE return an error although the DDL was applied, and an
--echo # in-place ALTER is then missing from the binary log.
--echo # Expected: a statement either fails with nothing applied and nothing logged,
--echo # or succeeds, is applied and is logged. This test FAILS while the bug exists.
--echo # (local verification only: needs strace + passwordless sudo)
--echo #

# Skip unless strace and passwordless sudo are available
--perl
  my $ok = system("which strace >/dev/null 2>&1") == 0
        && system("sudo -n true >/dev/null 2>&1") == 0;
  open(F, ">$ENV{MYSQLTEST_VARDIR}/tmp/mdev41636_skip.inc") or die $!;
  print F ($ok ? "" : "--skip needs strace and passwordless sudo\n");
  close F;
EOF
--source $MYSQLTEST_VARDIR/tmp/mdev41636_skip.inc

--let $failures= 0
--let $pid_file= `SELECT @@pid_file`
--let $helper= $MYSQL_TEST_DIR/std_data/strace_inject.sh
--let $ddl= $MYSQLTEST_VARDIR/mysqld.1/data/ddl_recovery.log
--let $trace= $MYSQLTEST_VARDIR/tmp/mdev41636.trace

CREATE TABLE t1 (id INT PRIMARY KEY, v INT) ENGINE=InnoDB;
INSERT INTO t1 VALUES (1,1);

--echo # ---------------------------------------------------------------
--echo # DROP TABLE t3: EIO on the N-th fdatasync of ddl_recovery.log, N = 1..6
--echo # (the report used ENOSPC on the 1st; the error type does not matter here)
--echo # ---------------------------------------------------------------
--let $n= 1
while ($n < 7)
{
  CREATE TABLE IF NOT EXISTS t3 LIKE t1;
  --let $g0= `SELECT @@gtid_binlog_pos`
  --exec INJECT_SYSCALLS=fdatasync INJECT_ACTION=error=EIO INJECT_WHEN=$n INJECT_PATH=$ddl sh $helper start $pid_file $trace
  --disable_abort_on_error
  DROP TABLE t3;
  --let $err= $mysql_errno
  --enable_abort_on_error
  --exec sh $helper stop $pid_file $trace
  --let $gone= `SELECT COUNT(*)=0 FROM information_schema.TABLES WHERE TABLE_SCHEMA='test' AND TABLE_NAME='t3'`
  --let $g1= `SELECT @@gtid_binlog_pos`
  --let $logged= `SELECT '$g0' != '$g1'`
  --echo # DROP TABLE, EIO on fdatasync #$n: errno=$err dropped=$gone binlogged=$logged
  --let $bad= `SELECT $err != 0 AND $gone = 1`
  if ($bad)
  {
    --echo FAIL: DROP TABLE returned error $err although the table was dropped (fdatasync #$n)
    --inc $failures
  }
  --inc $n
}

--echo # ---------------------------------------------------------------
--echo # ALTER TABLE t1 ADD COLUMN c1 INT (in-place): EIO on the N-th fdatasync, N = 1..6
--echo # (the report: the 5th sync, after the phase update DDL_ALTER_TABLE_PHASE_INPLACE_COPIED)
--echo # ---------------------------------------------------------------
--let $n= 1
while ($n < 7)
{
  DROP TABLE IF EXISTS t1;
  CREATE TABLE t1 (id INT PRIMARY KEY, v INT) ENGINE=InnoDB;
  INSERT INTO t1 VALUES (1,1);
  --let $g0= `SELECT @@gtid_binlog_pos`
  --exec INJECT_SYSCALLS=fdatasync INJECT_ACTION=error=EIO INJECT_WHEN=$n INJECT_PATH=$ddl sh $helper start $pid_file $trace
  --disable_abort_on_error
  ALTER TABLE t1 ADD COLUMN c1 INT, ALGORITHM=INPLACE;
  --let $err= $mysql_errno
  --enable_abort_on_error
  --exec sh $helper stop $pid_file $trace
  --let $applied= `SELECT COUNT(*) > 0 FROM information_schema.COLUMNS WHERE TABLE_SCHEMA='test' AND TABLE_NAME='t1' AND COLUMN_NAME='c1'`
  --let $g1= `SELECT @@gtid_binlog_pos`
  --let $logged= `SELECT '$g0' != '$g1'`
  --echo # ADD COLUMN, EIO on fdatasync #$n: errno=$err column_exists=$applied binlogged=$logged
  --let $bad= `SELECT $err != 0 AND $applied = 1`
  if ($bad)
  {
    --echo FAIL: ALTER TABLE returned error $err although the column was added (fdatasync #$n)
    --inc $failures
  }
  --let $bad= `SELECT $applied = 1 AND $logged = 0`
  if ($bad)
  {
    --echo FAIL: ALTER TABLE was applied but is MISSING from the binary log (fdatasync #$n)
    --inc $failures
  }
  --inc $n
}

--echo # The column added by the failed ALTER must survive a restart consistently
--source include/restart_mysqld.inc
SHOW CREATE TABLE t1;

--remove_file $trace
DROP TABLE IF EXISTS t1, t3;

if ($failures)
{
  --die MDEV-41636 reproduced: $failures check(s) failed (false DDL failures / missing binlog events)
}
--echo # all checks passed