[Dbix-class] Possible trouble with ResultSet::new_result, was: Why are these two relations different?

[John Napiorkowski]

I got some more details that I hope can help us
understand the problem.

Given the schema setup the way I described it I did a
Data::Dumper to try and figure out what is the main
difference between resultsets returned by the two
different relations:

use Data::Dumper;

print Dump ($documents->root_folders_a);
print Dump ($documents->root_folders_b);

Doing a diff on the two leads to just two minor
differences.  Under the
$documents->root_folders_a->{attrs}->{where} I get:

'where' => {
   'me.document_id' => '2'
}

Whereas with
$documents->root_folders_b->{attrs}->{where} I get:

'where' => {

   '-and' => [
      {
         'me.document_id' => '2'
      },
      {
         'parent_id' => \'IS NULL'
      }
   ]

}

Which makes total sense since the second relation has
an addition contraint.  Now it's this '-and' thing
that is causing the program to die when column_info
gets called (since there is no column called '-and'.) 
So I looked back to ResultSet::new_result() which is
where I think the error is occuring.  In that
new_result sub there are some lines (edited for
clarity):

foreach my $key (keys %{$self->{cond}||{}})
{
   $new{$1} = $self->{cond}{$key} 
    if ($key =~ m/^(?:\Q${alias}.\E)?([^.]+)$/);
}

Here, $self->{cond} appears to be a ref to
$self->{attrs}->{where}. So in my example for
$documents->root_folders_b this loops over a hash with
just one key in it '-and'.  For some reason this
'-and' value matches the regex and some the %new hash
ends up with a bad column name in it.

So at this point I am left with two possibilities (I
think).  Either:

1) $self->{cond} isn't pointing to the right thing (it
should probably ref the
...->{attrs}->{where}->{'-and'} instead of
...->{attrs}->{where}.

2) There is something wrong with this regex.

My best guess now is that the problem is more likely
to be 1.

I'm going to look into this further, but I really
think I'm a bit in over my head.  Is there anyone out
there who knows how this is supposed to work that can
point me in the right direction?

Also if I am not posting this to the correct list I
would appreciate it if someone could let me know. 
Thanks!

--john



> I don't understand why the two 'add_relationships'
> in
> the following behave so differently:
> 
> package Schema::Documents;
> 
> [all the normal setup for a schema]
> 
> __PACKAGE__->add_relationship(
> 
>   'root_folders_a', 
>   'Schema::bookmarks',  
>   {'foreign.document_id' => 'self.document_id'}, 
> 
> );
> 
> __PACKAGE__->add_relationship(
> 
>   'root_folders_b', 
>   'Schema::bookmarks', 
>   {'foreign.document_id' => 'self.document_id'}, 
>   { where => { 'parent_id' => \"IS NULL" } }
> );
> 
> sub root_folders_a
> {
>   my $self	= shift @_;
>   return $self->related_resultset('root_folders_a');
> }
> 
> sub root_folders_b
> {
>   my $self	= shift @_;
>   return $self->related_resultset('root_folders_b');
> }
> 
> my $schema = Schema->connect;
> my $documents = $schema->resultset('Documents');
> 
> my $documents->root_folders_a->create({...}); #WORKS
> my $documents->root_folders_b->create({...}); #DIES
> 
> The error I get for the second create is "No such
> column -and".  I traced this error message to a
> section of code in ResultSource.pm:
> 
> sub column_info {
>   my ($self, $column) = @_;
>   $self->throw_exception("No such column $column")
>     unless exists $self->_columns->{$column};
> [...]
> 
> Where it seems somebody tried to get info on the
> '-and' clause which I guess is part of how the
> system
> adds the constraints.  So I traced it further back
> to
> find out who is passing column_info such dubious
> information.  I found the following in ResultSet.pm:
> 
> sub new_result {
>   my ($self, $values) = @_;
>  [....]
>   my %new = %$values;
> 
> #Right now %new is a hash of all the real columns
> 
>   my $alias = $self->{attrs}{alias};
>   foreach my $key (keys %{$self->{cond}||{}}) {
>     $new{$1} = $self->{cond}{$key} if ($key =~
> m/^(?:\Q${alias}.\E)?([^.]+)$/);
>   }
> 
> #but after the loop above it's got the '-and' and
> some
> #other stuff.
> 
> [...]
> }
> 
> I don't understand the system well enough to
> determine
> if this area is the cause of the trouble.  This is
> as
> far as I could get.  Now I think for consistency
> that
> both relations should be able to call methods and
> such
> with equal results.  Why does it care if the
> relation
> is very simple or more complex?
> 
> Any thought or suggestions would be appreciated.
> 
> --john
> 
> 
> 
> 
> 
> 
> 
> __________________________________________________
> Do You Yahoo!?
> Tired of spam?  Yahoo! Mail has the best spam
> protection around 
> http://mail.yahoo.com 
> 
> _______________________________________________
> List:
>
http://lists.rawmode.org/cgi-bin/mailman/listinfo/dbix-class
> Wiki: http://dbix-class.shadowcatsystems.co.uk/
> IRC: irc.perl.org#dbix-class
> SVN:
>
http://dev.catalyst.perl.org/repos/bast/trunk/DBIx-Class/
> 


__________________________________________________
Do You Yahoo!?
Tired of spam?  Yahoo! Mail has the best spam protection around 
http://mail.yahoo.com