rename table to non-existent db with dir-per-db asserts

Description

https://bugs.launchpad.net/bugs/1645386
Also see

mysql> use test;
Database changed
mysql> show tables;
Empty set (0.00 sec)

mysql> set global tokudb_dir_per_db=true;
Query OK, 0 rows affected (0.00 sec)

mysql> create table t1 (id int auto_increment primary key not null) engine=tokudb;
Query OK, 0 rows affected (0.09 sec)

mysql> alter table test.t1 rename foo.t2;

#0  0x00007ffff6155c37 in __GI_raise (sig=sig@entry=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:56
        resultvar = 0
        pid = 32405
        selftid = 32500
#1  0x00007ffff6159028 in __GI_abort () at abort.c:89
        save_stage = 2
        act = {__sigaction_handler = {sa_handler = 0x0, sa_sigaction = 0x0}, sa_mask = {__val = {
              140737353508672, 140737353508768, 40960, 140737325687232, 140737322208914, 140737353508672, 
              140736663534467, 140737415839745, 140737325687232, 140737353508736, 175921860444183, 40959, 
              140737353467712, 140735869432218, 140735870156960, 140736493790464}}, sa_flags = 0, 
          sa_restorer = 0x7ffff7f6c9c0}
        sigs = {__val = {32, 0 <repeats 15 times>}}
#2  0x00007fffced63be0 in toku_do_backtrace_abort ()
    at /ssd/percona/myrocks-import/percona-server/storage/tokudb/PerconaFT/portability/toku_assert.cc:147
No locals.
#3  0x00007fffced63db7 in toku_do_assert_zero_fail (expr=2, expr_as_string=0x7fffced70437 "r", 
    function=0x7fffced72850 <can_acquire_table_lock(__toku_db_env*, __toku_db_txn*, char const*)::__FUNCTION__> "can_acquire_table_lock", 
    file=0x7fffced70838 "/ssd/percona/myrocks-import/percona-server/storage/tokudb/PerconaFT/src/ydb.cc", 
    line=2917, caller_errno=2)
    at /ssd/percona/myrocks-import/percona-server/storage/tokudb/PerconaFT/portability/toku_assert.cc:177
        msg = "/ssd/percona/myrocks-import/percona-server/storage/tokudb/PerconaFT/src/ydb.cc:2917 can_acquire_table_lock: Assertion `r == 0' failed (errno=2) (r=2)\n\000\000(\000\000\000\060\000\000\000\200i\366\367\377\177\000\000\300h\366\367\377\177\000\000\340h\366\367\377\177\000\000\240@\214\237\377\177\000\000\020i\366\367\377\177\000\000"...
#4  0x00007fffcec68953 in can_acquire_table_lock (env=0x7fffd23bcc00, txn=0x7ffff5830200, 
    iname_in_env=0x7fff9f8c40a0 "./foo/t2_main_7_2_1d.tokudb")
    at /ssd/percona/myrocks-import/percona-server/storage/tokudb/PerconaFT/src/ydb.cc:2917
        r = 2
        got_lock = false
        db = 0x7fff9f8ae380
        __FUNCTION__ = "can_acquire_table_lock"
#5  0x00007fffcec695d9 in env_dbrename (env=0x7fffd23bcc00, txn=0x7ffff5830200, 
    fname=0x7fff9f813500 "./test/t1-main", dbname=0x0, newname=0x7fff9f813380 "./foo/t2-main", flags=0)
    at /ssd/percona/myrocks-import/percona-server/storage/tokudb/PerconaFT/src/ydb.cc:3138
        new_iname_dbt = {data = 0x7fff9f8c40a0, size = 28, ulen = 0, flags = 0}
        new_iname = std::unique_ptr<char> containing 0x7fff9f8c40a0 "./foo/t2_main_7_2_1d.tokudb"
        dname = 0x7fff9f813500 "./test/t1-main"
        __FUNCTION__ = "env_dbrename"
        new_dname_dbt = {data = 0x7fff9f813380, size = 14, ulen = 0, flags = 0}
        iname_dbt = {data = 0x7fff9f878400, size = 29, ulen = 58, flags = 64}
        r = 0
        old_dname_dbt = {data = 0x7fff9f813500, size = 15, ulen = 0, flags = 0}
        iname = 0x7fff9f878400 "./test/t1_main_4_2_1d.tokudb"

gdb bt full log attached.

I am very surprised that the server does not validate that the target database exists before passing the command down to the storage engine. I imagine that either the SE ot the FT layer will need to detect this and return some kind of error.

Environment

None

Status

Percona-Server-5.6.35-80.0

Affects versions

Percona-Server-5.7.15-9

Percona-Server-5.6.33-79.0

Priority

Blocker