Hello,
This is in response to the comments on the initial pull request I made for adding RFC3339 support [1].
The proposal is to add support for parsing RFC3339 and then use the given timezone offset to shift the datetime. I think most users would expect the behavior to be converted to the timezone of the mariadb server / session as defined in THD. Most timezone operations are depended on the session specified timezone, whether that is set or inherited from global timezone, or system timezone.
In order to convert from RFC3339 timezone to session timezone, we will need to return the timezone from the str_to_datetime function. As mentioned there is no timezone member of the MY_TIME struct. I believe a change to the MY_TIME struct would be the most beneficial and cleanest approach. This would allow for handling RFC3339 and future additions, such as a datetime with time zone field, similar to the ansi timestamp with time zone. The struct is used in a several ways, including packing into longlong, all of those cases would need to be handled. This would be a much larger and more involved patchset.
An alternative approach, that is less involved, would be use the MYSQL_TIME_STATUS struct to indicate that a timezone offset exists. An offset field and indicator could be added right to the status struct, or a new warning can be used to indicate it exists in the raw string. Then the caller of str_to_datetime can handle the timezone conversion.
A third approach, would be to change the function signature of str_to_datetime and provide a variable to store the offset in, if exists. I'm sure what the general stance is on altering entire function calls, especially one that is older and quite important.
With any approach, the timezone could then be handled outside of my_time.c, where we have THD and the timezone class, which can easily handle the conversion.
I will start working on this once I receive some feedback on the general direction that would result in an acceptable patchset.
Thank you,
Seth Shelnutt