The affected code is well covered by tests for MDEV-8766.
Adding only the missing part: the old mode OLD_MODE_ZERO_DATE_TIME_CAST
in combination with 0000-MM-00 and YYYY-00-00.

The old mode in combination with 0000-00-DD was already covered,
so was the new mode with all types of DATETIME values.

Since MDEV-15091, the "lengh" parameter to str_to_time()
and str_to_datetime() is of type size_t rather than uint.
Fixing Time(), Temporal_with_date() and Datetime() constructors accordingly.

The bug did not affect behaviour in any way though :)

MDEV-16935 Change the parameter of Field_xxx::store_TIME_with_dec() to const Datetime* and const Time*

MDEV-16928 Move MYSQL_TIME initialization from Field_xxx::store_time_dec() to new constructors Time() and Datetime()

- Adding a helper class Sec6 to store (neg,seconds,microseconds)
- Adding a helper class VSec6 (Sec6  with a flag for "IS NULL")
- Wrapping related functions as methods of Sec6;
  * number_to_datetime()
  * number_to_time()
  * my_decimal2seconds()
  * Item::get_seconds()
  * A big piece of code in Item_func_sec_to_time::get_date()

- Using the new classes in places where second-to-temporal
  conversion takes place:
  * Field_timestamp::store(double)
  * Field_timestamp::store(longlong)
  * Field_timestamp_with_dec::store_decimal(my_decimal)
  * Field_temporal_with_date::store(double)
  * Field_temporal_with_date::store(longlong)
  * Field_time::store(double)
  * Field_time::store(longlong)
  * Field_time::store_decimal(my_decimal)
  * Field_temporal_with_date::store_decimal(my_decimal)
  * get_interval_value()
  * Item_func_sec_to_time::get_date()
  * Item_func_from_unixtime::get_date()
  * Item_func_maketime::get_date()
  This change simplifies these methods and functions a lot.

- Warnings are now sent at VSec6 initialization time, when the source
  data is available in its original data type representation.

  If Sec6::to_time() or Sec6::to_datetime() truncate data again during
  conversion to MYSQL_TIME, they send warnings, but only if no warnings
  were sent during VSec6 initialization. This helps prevents double warnings.

  The call for val_str() in Item_func_sec_to_time::get_date() is not
  needed any more, so it's removed. This change actually fixes the problem.

  As a good effect, FROM_UNIXTIME() and MAKETIME() now also send warnings
  in case if the seconds arguments is out of range. Previously these
  functions returned NULL silently.

- Splitting the code in the global function make_truncated_value_warning()
  into a number of methods THD::raise_warning_xxxx().
  This was needed to reuse the logic that chooses between:
  * ER_TRUNCATED_WRONG_VALUE
  * ER_WRONG_VALUE
  * ER_TRUNCATED_WRONG_VALUE_FOR_FIELD
  for non-temporal data types (Sec6).

- Removing:
  * Item::get_seconds()
  * number_to_time_with_warn()
  as this code now resides inside methods of Sec6.

- Cleanup (changes that are not directly related to the fix):
  * Removing calls for field_name_or_null() and passing NULL instead
    in Item_func_hybrid_field_type::get_date_from_{int|real}_op,
    because Item_func_hybrid_field_type::field_name_or_null()
    always returns NULL
  * Replacing a number of calls for make_truncated_value_warning()
    to calls for THD::raise_warning_xxx(). In these places
    we know that the execution went through a certain
    branch of make_truncated_value_warning(),
    (e.g. the exact error code is known, or field name is always NULL,
     or field name is always not-NULL). So calls for the entire
    make_truncated_value_warning() after splitting are not necessary.

If something was built using a build dependency, it will automatically
be a install dependency via ${shlibs:Depends}, so no need to define it
manually.

This also fixes a bug related to a over autobake-deb.sh mangling
the control file architecture field on Trusty and Jessie.

Changing data types for:
- seconds from longlong to ulonglong
- microseconds from long to ulong
in:
- parameters of calc_time_diff()
- parameters of calc_time_from_sec()
- Members of Sec6_add

This will help to reuse the code easier:
all other functions use ulonglong+long
for seconds/microsecond, e.g.:

- number_to_time()
- number_to_datetime()
- number_to_datetime_with_warn()
- Field_temporal_with_date::store_decimal()
- my_decimal2seconds()
- Item::get_seconds()

Adding classes VDec and VDec2_lazy, according to the task description.
This patch removes around 250 duplicate code lines.

This also better matches the package order in downstream, so it makes
it easier to compare upstream and downstream. Also wrap-and-sort.

After this there will be no need to maintain line numbers, as the
extent of the sed deletion will automatically be until next empty line.

- Update package names that had -10.3 to -10.4
- Update conflicts/breaks/replaces of to include now also 10.3,
  just like 10.3 had the same relationship to 10.2
- Remove some old  (<< ${source:Version}) not needed anymore as we
  are not moving files around inside the 10.4 releases (at least yet).
- Ensure all plugins depend on server or client binaries from the same
  release so that they for sure are binary API compatible.

Due to an obvious bug in st_select_lex_unit::reset_distinct() a union
without duplicates of more than 2 selects could return a result set
containing duplicate rows if this union was enclosed in ().

The bug appeares because of the lamely saved list of multiple equalities.
To fix it and_new_conditions_to_optimized_cond() was changed.

- Implementing the task according to the MDEV description.
- Adding a helper class Sec6_add to share the code in type-specific
  branches in Item_func_add_time::get_date().

The problem appears because of the pushdown of a non-pushable condition 'cond'
into the materialized derived table/view. To prevent pushdown a map of
tables that are used in 'cond' should be updated. This call is missing
because of the MDEV-12387 changes. The call is added in the
setup_jtbm_semi_joins() method.

failed

The bug appeared as in MDEV-12387 setup_jtbm_semi_joins() procedure had been
devided into two functions, one called before optimization of WHERE clause
and another after this optimization. When the second function was called for
a degenerated jtbm semi join equalities connecting the subselect and
the parent select were created but invocation of fix_fields() for these
equalities was missing.

Adding new methods:

- virtual void Type_handler::Column_definition_reuse_fix_attributes()
  according to the MDEV description

- virtual uint32 Field::character_octet_length()
  To simplify handling of Column_definition::length for
  TEXT and VARCHAR columns (with and without compression).

The problem occurred because the Spider node was incorrectly handling
timestamp values sent to and received from the data nodes.

The problem has been corrected as follows:
- Added logic to set and maintain the UTC time zone on the data nodes.
  To prevent timestamp ambiguity, it is necessary for the data nodes to use
  a time zone such as UTC which does not have daylight savings time.
- Removed the spider_sync_time_zone configuration variable, which did not
  solve the problem and which interfered with the solution.
- Added logic to convert to the UTC time zone all timestamp values sent to
  and received from the data nodes.  This is done for both unique and
  non-unique timestamp columns.  It is done for WHERE clauses, applying to
  SELECT, UPDATE and DELETE statements, and for UPDATE columns.
- Disabled Spider's use of direct update when any of the columns to update is
  a timestamp column.  This is necessary to prevent false duplicate key value
  errors.
- Added a new test spider.timestamp to thoroughly test Spider's handling of
  timestamp values.

Author:
  Jacob Mathew.

Reviewer:
  Kentoku Shiba.

Merged:
  Commit 97cc9d34 on branch bb-10.3-MDEV-16246

Field_varstring::sql_type() did not calculate character length correctly.
Using char_length() instead of the bad code.