[html-formfu] Possible H::FF::M::DBIC bug with deeply nested relationships

Peter Shangov pshangov at yahoo.com
Fri Jun 17 12:15:56 GMT 2011

Hi all,

I was working on a fix for a strange issue where H::FF::M::DBIC will attempt to create an empty related row when no values were submitted for that relationship, and while trying to reproduce it in a test I stumbled upon a possible bug that might mess up with the saving of nested blocks (I wanted to add an ignore_if_empty option for blocks, hence the name of the test below).

You will need to get a copy of my fork and switch to the ignore-if-empty-block branch:

  git clone git://github.com/pshangov/HTML-FormFu-Model-DBIC.git
  git checkout ignore-if-empty-block

And then have a look at t\update\ignore-if-empty-block.t and t\update\ignore-if-empty-block.yml.

In short, if I try to process my form with the following arguments:

  # resulset is MySchema::User, has_many 'addresses'
  'name'                     => 'Peter',
  'addresses_counter'        => '1',
  'addresses_1.address'      => '1 Baker Street',
  'addresses_1.id'           => '',
  'addresses_1.city.name'    => 'London',

the 'city' relationship will be ignored and address.city_id' will be undef. This happens because H::FF::M::DBIC::_save_relationships does the following:

  # $rel is 'city'
  my $params = $form->param($rel); # undef, do not save anything

It seems this will fail to fetch parameters for any element with a 'nested_name' that is not a direct child of the top-level form. Curiously, I can get it to work with the following trick:

  # Add fake relationship via 'city.id' (the form needs to be modified too)
  'name'                     => 'Peter',
  'city.id'                  => 'whatever'
  'addresses_counter'        => '1',

  my $params = $form->param($rel); # { id => 'whatever' }, so proceed with saving addresses.city
                                   # address.city_id is now correctly set to '1'

I am not really sure how I should fix that. What is the correct way to fetch the parameters for a relationship that is nested more than one level deep?



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