plperl - make $_TD global
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 what we had is strictly a bug, so I don't thinbk we need
top backpatch this.
It will, however, require use of perl 5.6 at a minimum, because that's
when the "our" function came in. Since that was over 6 years ago, I
think this is not unreasonable. If there are squawks, I have another
slightly longer and slightly more old-fashioned way to do the same
thing, but this is the best modern way.
I don't think a docs change is needed.
If there's no objection I will apply thin in a few days.
cheers
andrew
Attachments:
plperl-td.patchtext/x-patch; name=plperl-td.patchDownload+2-2
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)?
regards, tom lane
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
Andrew Dunstan wrote:
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.
Yes, I think something for docs would be good.
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