94eb819...
by
Rucha Deodhar <email address hidden>
MDEV-31684 Add timezone information to DATE_FORMAT
Before starting to go over the format string, prepare the current time
zone information incase '%z' or '%Z' is encountered.
This information can be obtained as given below:
A) If timezone is not set ( meaning we are working with system timezone):
Get the MYSQL_TIME representation for current time and GMT time using
current thread variable for timezone and timezone variable for UTC
respectively. This MYSQL_TIME variable will be used to calculate time
difference. Also convert current time in second to tm structure to
get system timezone information.
B) If timezone is set as offset:
Get timezone information using current timezone information and store
in appropriate variable.
C) If timezone is set as some place (example: Europe/Berlin)
Get timezone information by searching the timezone. During internal
timezone search, information like timeoffset from UTC and abbrevation
is stored in another relevant structure. Hence use the same information.
remove old deprecation helpers that were not used anywhere.
create new deprecation helpers and enforce their usage
this also removes inconsistencies in reporting deprecation:
sometimes it was ER_WARN_DEPRECATED_SYNTAX (1287),
sometimes ER_WARN_DEPRECATED_SYNTAX_NO_REPLACEMENT (1681),
sometimes a warning, sometimes a note.
it should always be
* ER_WARN_DEPRECATED_SYNTAX
* a warning (because it's something actionable, not purely informational)
it was introduced in ff8651c4ecb to suppress deprecated
warnings for CALL under the flawed logic that "It's doesn't
make sense to print out deprecated syntax warnings when the
routine is being executed because this kind of warning only
matters when the routine is being created".
Which is incorrect, a feature might become deprecated after
the routine was created and a user has to know that to be able
to update the procedure before it stops working when a
deprecated feature is removed.
