[Catalyst] Duplicate entries with C::P::Session::Store::DBIC and MySQL

[Tobias Kremer]

On 29 Jul 2008, at 12:30, Tobias Kremer wrote:
> The short time window between the find() and create() calls of the
> find_or_create() method indeed is the problem. It sounds like this
> window should be too small to ever happen but in reality it happens very
> often in our (and other's) applications. I can force the problem by
> hammering reload in my browser.

Because the duplicate entry errors are multiplying like crazy, I'm in a
desperate need for a quick fix. So, until we fix DBIC's find_or_create()
method, I'm thinking about adding the following snippet to MyApp.pm after
setup():

    *{Catalyst::Plugin::Session::Store::DBIC::Delegate::flash} = sub {
        my ($self, $key) = @_;
        my $row = $self->_flash_row;
        unless ($row) {
            eval {
                $row = $self->model->create({ $self->id_field => $key });
            };
            if( $@ ) {
                die $@ unless $@ =~ /Duplicate entry/;
                $row = $self->model->find({ $self->id_field => $key });
            }
            $self->_flash_row($row);
        }
        return $row;
    };

Because I really don't like poking around in the symbol table and I'm completely
unsure what side-effects this may cause, I'd like to ask for your comments on
this. Could this be a quick-hack-remedy for the problem at hand or will this
screw things up big-time?

Thanks!

--Tobias