[Dbix-class] Schema reference object disapears from my resultset when building collections

[Ash Berlin]

Jason Wieland wrote:
> Hello,
> I hope everyone is having a good day.  I've been pulling my hair out
> about this issue for a while and I hope someone can help me.  First let
> me commend the authors for DBIx,  after 8 years of witting sql I'm
> getting pretty sick of it, thank you.
> 
> I have a two layered system:
> first perl module called pcGame.pm that handles business logic
> and a second module called PocketCombat.pm that handles the data access
> layer
> 
> OO'ish style to separate the Data Objects from the Business Objects.
> Obviously I integrated DBIx into my Data Objects.  Everything was going
> fine until I started building collections (object factories).
> 
> I want to gather all games from a certain customer (similar to gathering
> all books from an author, from the common examples).
> 
> pcGame.pm:
> .....
> $games = PocketDO::PocketCombat->find( -owner => $profile );
> ......
> 
> ($games is an array ref of all the game objects that are owned by a 
> profile)
> 
> PocketCombat.pm
> .....
>   my $rs = $self->_dataRs->search(
>                                    {
>                                        'me.profile' => $in{-owner}->id
>                                    },
>                                    );
> 
>    my @games;
>    while (my $game_rs = $rs->next) {
>        my $game = __PACKAGE__->_new($pkg);
>        $game->{data} = $game_rs;
>        $game->{id} = $game->{data}->gameid;
>        push @games, $game;
>    }
> return \@games;
> 
> 
> When I start to query the data in pcGame.pm I get this error
> Can't call method "source" on an undefined value at
> /usr/lib/perl5/site_perl/5.8.8/DBIx/Class/ResultSource.pm line 907.
> 
> Everything in $game->{data} works great until it is returned back to
> pcGame.pm
> 
> It looks like part of the resultset data structure vanishes, in
> particular the 'schema' object reference.
> This is what a Dumper of the first element of the array looks like
> before it is returned:
> http://www.patnjay.org/pre_return_datastructure.txt
> and right after it is returned it looks like this
> http://www.patnjay.org/post_return_datastructure.txt
> 
> The only change between the two dumps is that 'schema' => undef
> 
> I have found two roundabout solutions that I don't like.  If in the Data
> layer while looping through the rs->next, I call all my accessors that I
> plan on using
> $game->type;
> $game->state;
> .....
> If I preload all this data it will be accessible from the pcGame.pm
> However this make maintenance a nightmare.
> 
> The second (crappy) solution is to clone the resultset as I add it the
> object
> $game->{data} = clone($game_rs);
> instead of
> $game->{data} = $game_rs;
> Clone coming from http://search.cpan.org/~rdf/Clone-0.22/Clone.pm
> 
> I would rather not do this because Clone has other issues that I would
> need to deal with.
> 
> Anyone see this issue before?  Or have any suggestions.
> 
> Thanks,
> 
> Jason Wieland
> 

How are you populating $self->_dataRs? Are you a using 
Storable::clone/freeze/thaw somewhere?

  If this is the case, you will _have_ to reset the schema reference 
after thaw/clone.

We probably need to 1) document this, and 2) provide better hooks to 
reset the schema.

Ash