--source include/not_windows.inc
--source include/not_embedded.inc

--echo #
--echo # MDEV-5479: Prevent mysqld from unlinking a Unix socket
--echo #            file actively used by another process
--echo #

# Shut down the server once; both tests run while it is down.
--source include/shutdown_mysqld.inc

--echo #
--echo # Test 1: Server must refuse to start when a listener is
--echo #         already present on the socket path
--echo #

# Create a fake listener on the default socket path.
# The parent creates the socket, then exits (fork and exit).
# The child blocks on accept(); when mysqld's connect() probe
# hits the socket, accept() returns and the child exits,
# leaving a stale socket file for Test 2.
perl;
  use IO::Socket::UNIX;
  my $path= $ENV{MASTER_MYSOCK};
  unlink $path;
  close STDOUT;
  my $srv= IO::Socket::UNIX->new(
    Local  => $path,
    Listen => 1,
  ) or die "IO::Socket::UNIX->new($path): $!";
  fork and exit;
  exit if $srv->accept();
EOF

--let errorlog=$MYSQL_TMP_DIR/socket_conflict.err
--let SEARCH_FILE=$errorlog

# Use --loose-skip-innodb to skip InnoDB initialization, which
# runs before network_init() and would otherwise be slow on CI.
--error 1
--exec $MYSQLD --defaults-group-suffix=.1 --defaults-file=$MYSQLTEST_VARDIR/my.cnf --loose-skip-innodb --log-error=$errorlog

--let SEARCH_PATTERN=\[ERROR\] Another process is already listening on the socket file
--source include/search_pattern_in_file.inc

--remove_file $SEARCH_FILE

--echo #
--echo # Test 2: Stale socket file must be cleaned up at startup
--echo #

# The socket file from Test 1 is still on disk but has no
# listener. The server should detect it as stale, remove it,
# and bind successfully.
--source include/start_mysqld.inc

# Verify the server is operational
SELECT 1;

--echo # End of 10.11 tests