This change is a backport from 10.0 to 5.5 for:
1. The full patch for:
MDEV-4841 Wrong character set of ADDTIME() and DATE_ADD()
9adb6e991e
2. A small fragment of:
MDEV-5298 Illegal mix of collations on timestamp
03f6778d61
which overrides Item_temporal_hybrid_func::cmp_type(),
and adds a new line into cache_temporal_4265.result.
This reverts commit 035a5ac62a.
Two minor problems and one regression:
1. caching the value in str_result. Other Item methods may use it,
destroying the cache. See, for example, Item::save_in_field, where
str_result is moved to use a local buffer (this failed main.grant)
2. Item_func_conv_charset::safe is now set too late, it's initialized
only in val_str() but checked before that, this failed many tests
in optimized builds.
to fix 1 - use tmp_result instead of str_result, to fix 2, use
the else branch in the Item_func_conv_charset constructor to set
safe purely from charset properties.
But this introduces a regression, constant strings can no longer be
converted, say, from utf8 to latin1 (because 'safe' will be false).
This fails few tests too. There is no way to fix it without reverting
the commit and converting constants, as before, in the constructor.
Server may crash if sanity checks of COLUMN_GET() fail.
COLUMN_GET() description generator expects parent CAST item, which may not have
been created due to failure of sanity checks. Then further attempt to report
an error may crash the server.
Fixed COLUMN_GET() description generator to handle such case.
~40% bugfixed(*) applied
~40$ bugfixed reverted (incorrect or we're not buggy)
~20% bugfixed applied, despite us being not buggy
(*) only changes in the server code, e.g. not cmakefiles
MDEV-6099 Bad results for DATE_ADD(.., INTERVAL 2000000000000000000.0 SECOND)
MDEV-6097 Inconsistent results for CAST(int,decimal,double AS DATETIME)
MDEV-6100 No warning on CAST(9000000 AS TIME)
on server shutdown after SELECT with CONVERT_TZ
It's wrong to return my_empty_string from val_str().
Removing my_empty_string. Using make_empty_result() instead.
Other fix of maybe_null problem and revert of revno: 3608 "MDEV-3873 & MDEV-3876 & MDEV-3912 : Wrong result (extra rows) with ALL subquery from a MERGE view."
Cleanup: remove TIME_FUZZY_DATE.
Introduce TIME_FUZZY_DATES which means "very fuzzy, the resulting
value is only used for comparison. It can be invalid date, fine, as long as it can be
compared".
Updated many tests results (they're better now).
Item_func_make_set wasn't taking into account the first argument when
calculating maybe_null.
sql/item_strfunc.cc:
rewrite Item_func_make_set, removing separate storage of the first argument
sql/item_strfunc.h:
rewrite Item_func_make_set, removing separate storage of the first argument
from a MERGE view.
The problem was in the lost ability to be null for the table of a left join if it
is a view/derived table.
It hapenned because setup_table_map(), was called earlier then we merged
the view or derived.
Fixed by propagating new maybe_null flag during Item::update_used_tables().
Change in join_outer.test and join_outer_jcl6.test appeared because
IS NULL reported no used tables (i.e. constant) for argument which could not be
NULL and new maybe_null flag was propagated for IS NULL argument (Item_field)
because table the Item_field belonged to changed its maybe_null status.
