Re: plperl - make $_TD global

Tom Lane wrote:

>Andrew Dunstan <andrew@dunslane.net> writes:
>
>
>>The attached tiny patch will fix the problem Greg Sabino Mullane had
>>with a shared lexical $_TD, by making it a global and just pushing a
>>local value in the trigger function.
>>...
>>I don't think a docs change is needed.
>>
>>
>
>Are you sure this doesn't cause any user-visible semantics change
>(ie, something that might break someone's code)?
>
>
>
>

I think it should be mentioned in the release notes.

I would be fairly stretched to come up with an example that it breaks.
Essentially it's a way around the sharing violation that Greg got from
using $_TD in a nested subroutine. All we are doing is moving $_TD from
the local namespace to the global namespace. It still gets a per
trigger-call value (that's what the "local $_TD = $_[0];" does) and that
will work correctly even under recursive calls, so I think it's fairly safe.

Maybe it is worth putting somethng in the plperl Trigger docs about the
nature of the beast. I will do that if you like.

cheers

andrew