TVC uses derived as singlatable calls

When compiling CMAKE_BUILD_TYPE=Debug WITH_ASAN using clang-7 -O2
the following tests could fail due to insufficient stack size:
main.signal_demo3 sys_vars.max_sp_recursion_depth_func

In commit d30f17af the change of
the loop iteration broke another error handling path that did
"goto error_handling_drop_uncached". Cover this code path with
fault injection, and revert to the correct iteration.

There are two fault injection labels innodb_OOM_prepare_inplace_alter.
Their order was swapped in MDEV-11369, so that the label that used
to be covered in an ADD INDEX code path would become unreachable
because the label that is executed for any ALTER TABLE was executed
first. Let us introduce the label innodb_OOM_prepare_add_index
for the more specific case.

The 10.1 changes to the test case were accidentally omitted
in the merge commit 913e33e4.

The test case was accidentally omitted from the merge
commit 913e33e4.

GCC does not like MY_ATTRIBUTE((nonnull)) on a reference-to-pointer
parameter. clang did not flag an issue wit that.

Rewrite the MDEV-13818 fix to prevent heap-use-after-free.

Add a test case for MDEV-18272.

if create_index_dict() fails, we need to free ctx->add_index[a] too

This fixes innodb.alter_crash and innodb.instant_alter_debug
failures in ASAN_OPTIONS="abort_on_error=1" runs

This fixes main.mysql_client_test, main.mysql_client_test_comp,
main.mysql_client_test_nonblock failures
in ASAN_OPTIONS="abort_on_error=1" runs

row_merge_create_index_graph(): Relay the internal state
from dict_create_index_step(). Our caller should free the index
only if it was not copied, added to the cache, and freed.

row_merge_create_index(): Free the index template if it was
not added to the cache. This is a safer variant of the logic
that was introduced in 65070bef in 10.2.

prepare_inplace_alter_table_dict(): Add additional fault injection
to exercise a code path where we have already added an index
to the cache.

row_mysql_handle_errors(): Correct the wrong error handling for
the code DB_FOREIGN_EXCEED_MAX_CASCADE that was introduced in

https://github.com/mysql/mysql-server/commit/c0923d396aef46799883390e9dcf7bbf173e4a03

    commit 35f5429e
    Author: Jimmy Yang <jimmy.yang@oracle.com>
    Date:   Wed Oct 6 06:55:34 2010 -0700

        Manual port Bug #Bug #54582 "stack overflow when opening many tables
        linked with foreign keys at once" from mysql-5.1-security to
        mysql-5.5-security again.

        rb://391 approved by Heikki

No known test case exists for repeating the bug before MariaDB 10.2.
The scenario should be that DB_FOREIGN_EXCEED_MAX_CASCADE is returned,
then InnoDB wrongly skips the rollback to the start of the current
row operation, and finally the SQL layer commits the transaction.
Normally the SQL layer would roll back either the entire transaction or
to the start of the statement. In the faulty scenario, InnoDB would
leave the transaction in an inconsistent state, and the SQL layer could
commit the transaction.

using Item_cond

This bug is similar to the bug MDEV-16765.
It appears because of the wrong pushdown into HAVING clause while this
pushdown shouldn't be made at all.
This happens because function that checks if Item_cond can be pushed
always returns that it can be pushed.

To fix it new method Item_cond::excl_dep_on_table() was added.

After-merge fix for MDEV-18333 Slow_queries count doesn't increase when slow_query_log is turned off

This fixes main.mysql_client_test, main.mysql_client_test_comp,
main.mysql_client_test_nonblock failures
in ASAN_OPTIONS="abort_on_error=1" runs

don't initialize mysql structure before it actually becomes needed.

This fixes main.mysqladmin failures
in ASAN_OPTIONS="abort_on_error=1" runs

free already allocated indexes if row_merge_create_index() fails

This fixes innodb.alter_crash failure
in ASAN_OPTIONS="abort_on_error=1" runs

use the correct delete operator

This fixes mroonga/storage.column_generated_stored_add_column failures
in ASAN_OPTIONS="abort_on_error=1" runs

MDEV-18625 ASAN unknown-crash in my_copy_fix_mb / ha_mroonga::storage_inplace_alter_table_add_column

disable inplace alter for adding stored generated columns.

This fixes mroonga/storage.column_generated_stored_add_column failures
in ASAN_OPTIONS="abort_on_error=1" runs

Also, add a test case that shows the bug without ASAN.

fixes these test failures in ASAN builds (in 10.1 and 10.4):
* main.signal_demo3
* main.sp
* sys_vars.max_sp_recursion_depth_func
* mroonga/storage.foreign_key_delete_existent
* mroonga/storage.foreign_key_delete_nonexistent
* mroonga/storage.foreign_key_insert_existent
* mroonga/storage.foreign_key_update_existent
* mroonga/storage.foreign_key_update_nonexistent
* mroonga/storage.function_command_auto-escape
* mroonga/storage.function_command_select
* mroonga/storage.variable_enable_operations_recording_insert

thd->lex->m_sql_cmd was not cleared between queries.
log_slow_query() could crash (when running mtr --ps) because of this.

I know no test case for this bug in 10.1. So a test case will be
committed separately in 10.2

fts_reset_get_doc(): properly initialize fts_get_doc_t::cache

fts_fetch_index_words(): Restore the initialization len=0.
The test innodb_fts.create in 10.2 would end up in an infinite loop
if this assignment is removed, because a following iteration of the
while() loop would assign zip->zp->avail_in=len with the original value
instead of the 0 that was reset in the previous iteration.

Fix the warnings issued by GCC 8 -Wstringop-truncation
and -Wstringop-overflow in InnoDB and XtraDB.

This work is motivated by Jan Lindström. The patch mainly differs
from his original one as follows:

(1) We remove explicit initialization of stack-allocated string buffers.
The minimum amount of initialization that is needed is a terminating
NUL character.
(2) GCC issues a warning for invoking strncpy(dest, src, sizeof dest)
because if strlen(src) >= sizeof dest, there would be no terminating
NUL byte in dest. We avoid this problem by invoking strncpy() with
a limit that is 1 less than the buffer size, and by always writing
NUL to the last byte of the buffer.
(3) We replace strncpy() with memcpy() or strcpy() in those cases
when the result is functionally equivalent.

Note: fts_fetch_index_words() never deals with len==UNIV_SQL_NULL.
This was enforced by an assertion that limits the maximum length
to FTS_MAX_WORD_LEN. Also, the encoding that InnoDB uses for
the compressed fulltext index is not byte-order agnostic, that is,
InnoDB data files that use FULLTEXT INDEX are not portable between
big-endian and little-endian systems.

row_merge_create_fts_sort_index(): Initialize dict_col_t.

This fixes an access to uninitialized dict_col_t::ind when a debug
assertion in MariaDB 10.4 invokes is_dropped() in
rec_get_converted_size_comp_prefix_low(). Older MariaDB versions
seem to be unaffected by the uninitialized values, but it should
not hurt to initialize everything.

FIXME: Properly resolve conflicts between MDEV-18883
and MDEV-7742/MDEV-8305, and record the correct result for
main.log_slow

If a splittable materialized derived table / view T is used in a inner nest
of an outer join with impossible ON condition then T is marked as a
constant table. Yet the execution plan to build T is still searched for
in spite of the fact that is not needed. So it should be set.

Lesson learned: A HA_TOPTION_SYSVAR that is bound to
MYSQL_THDVAR_UINT does not have the type uint, but ulonglong.