Assert fail in field.cc

The easiest way to reproduce this bug is to copy the whole directory rpl_encryption from branch 57_binlog_encryption_2ndPR. Modify rpl_encryption/my.cnf and disable encypt-binlog option (server does not provide this option as binlog feature is not yet merged in). Run rpl_encryption.encrypted_master, you will see the stack trace:

#0 __pthread_kill (threadid=<optimized out>, signo=6) at ../sysdeps/unix/sysv/linux/pthread_kill.c:62
#1 0x00000000019c5c32 in my_write_core (sig=6) at /home/rob/git/percona-server/mysys/stacktrace.c:249
#2 0x0000000000f43594 in handle_fatal_signal (sig=6) at /home/rob/git/percona-server/sql/signal_handler.cc:223
#3 <signal handler called>
#4 0x00007f5ed7e39428 in __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:54
#5 0x00007f5ed7e3b02a in __GI_abort () at abort.c:89
#6 0x00007f5ed7e31bd7 in __assert_fail_base (fmt=<optimized out>, assertion=assertion@entry=0x1fecdb8 "!table || (!table->write_set || bitmap_is_set(table->write_set, field_index))", file=file@entry=0x1fecc00 "/home/rob/git/percona-server/sql/field.cc", line=line@entry=4121, function=function@entry=0x1fef680 <Field_long::store(long long, bool)::__PRETTY_FUNCTION__> "virtual type_conversion_status Field_long::store(longlong, bool)") at assert.c:92
#7 0x00007f5ed7e31c82 in __GI___assert_fail (assertion=0x1fecdb8 "!table || (!table->write_set || bitmap_is_set(table->write_set, field_index))", file=0x1fecc00 "/home/rob/git/percona-server/sql/field.cc", line=4121, function=0x1fef680 <Field_long::store(long long, bool)::__PRETTY_FUNCTION__> "virtual type_conversion_status Field_long::store(longlong, bool)") at assert.c:101
#8 0x0000000000fa15fd in Field_long::store (this=0x7f5e600ad658, nr=9, unsigned_val=false) at /home/rob/git/percona-server/sql/field.cc:4121
#9 0x0000000001007675 in Item::save_in_field_inner (this=0x7f5e600aed70, field=0x7f5e600ad658, no_conversions=false) at /home/rob/git/percona-server/sql/item.cc:6884
#10 0x0000000001006c74 in Item::save_in_field (this=0x7f5e600aed70, field=0x7f5e600ad658, no_conversions=false) at /home/rob/git/percona-server/sql/item.cc:6750
#11 0x000000000176948d in update_generated_read_fields (buf=0x7f5e60064130 "\364W\002", table=0x7f5e600afc50, active_index=64) at /home/rob/git/percona-server/sql/table.cc:7899
#12 0x0000000000fdb895 in handler::ha_rnd_pos (this=0x7f5e600638b0, buf=0x7f5e60064130 "\364W\002", pos=0x7f5e600b4608 "\002") at /home/rob/git/percona-server/sql/handler.cc:3181
#13 0x0000000001a5b08c in ha_innopart::rnd_pos_by_record (this=0x7f5e600638b0, record=0x7f5e60064130 "\364W\002") at /home/rob/git/percona-server/storage/innobase/handler/ha_innopart.cc:4549
#14 0x00000000018f81a0 in Rows_log_event::do_index_scan_and_update (this=0x7f5e600a9f00, rli=0x4fa6d80) at /home/rob/git/percona-server/sql/log_event.cc:10339
#15 0x00000000018fa727 in Rows_log_event::do_apply_event (this=0x7f5e600a9f00, rli=0x4fa6d80) at /home/rob/git/percona-server/sql/log_event.cc:11227
#16 0x00000000018e1480 in Log_event::apply_event (this=0x7f5e600a9f00, rli=0x4fa6d80) at /home/rob/git/percona-server/sql/log_event.cc:3447
#17 0x000000000195d47e in apply_event_and_update_pos (ptr_ev=0x7f5ed12998a0, thd=0x7f5e600008c0, rli=0x4fa6d80) at /home/rob/git/percona-server/sql/rpl_slave.cc:4760
#18 0x000000000195ec46 in exec_relay_log_event (thd=0x7f5e600008c0, rli=0x4fa6d80) at /home/rob/git/percona-server/sql/rpl_slave.cc:5275
#19 0x0000000001966036 in handle_slave_sql (arg=0x4f50aa0) at /home/rob/git/percona-server/sql/rpl_slave.cc:7490
#20 0x0000000001eb83a3 in pfs_spawn_thread (arg=0x7f5e741974f0) at /home/rob/git/percona-server/storage/perfschema/pfs.cc:2190
#21 0x00007f5ed8a766ba in start_thread (arg=0x7f5ed129a700) at pthread_create.c:333
#22 0x00007f5ed7f0b3dd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

From initial investigation problem is that newly added function : int
ha_innopart::rnd_pos_by_record(uchar* record) is initializing only partition where record was found. The old version of this function did ha_rnd_init() when called from int Rows_log_event::do_index_scan_and_update(Relay_log_info const *rli)