byterock

Still make errors pretty day here in the Moose-Pen.
Yesterday I re-discovered that I had 'MooseX::Constructor::AllErrors' set up in my code. I was even using it to test fail conditions like this test;

$in_hash = {

    view => {

        name  => undef,

        alias => undef

    }

};

eval { 

    $da = Database::Accessor->new($in_hash); 

    };

ok( $@->has_errors(),          "Error on New" );

ok( scalar( $@->errors ) == 2, "Two errors on new" );

...

in test case '30_view.t'

This MooseX gathers up all Constructor errors and puts them in a nice 'error-class' and then returns that class with the '$@'. So all along I was getting the that you can play with. It even clasifies the errors for you into 3 attributes

• missing


• lists all 'required' elements that are missing;


• invalid


• lists any type or coecion errors and;


• misc


• any other errors no listed above.

Now this is all nice and good as my end users get a object they can work with but I still want to make it easer for them. but and I think I can work with this to fix up the error messages a little. I will have to put into my documentation that the end user can use that if they want to capture these errors themselves.
Now for today’s mission make my errors a little more friendly. Moose actually helps me out here and I am going to try and take advantage of the 'around BUILDARGS' to change my error message;

As it stands now I have just this;

around BUILDARGS => sub {

        my $orig  = shift;

        my $class = shift;

        my $ops   = shift(@_);

        if ( $ops->{retrieve_only} ) {

            $ops->{no_create}   = 1;

            $ops->{no_retrieve} = 0;

            $ops->{no_update}   = 1;

            $ops->{no_delete}   = 1;

        }

        return $class->$orig($ops);

    };

Very standard stuff right out of the Moose::Cookbook. Now a few quick changes to this patten to get me off that well worn track;

...

            $ops->{no_delete}   = 1;

        }

--      return $class->$orig($ops);

++      my $instance;

++      eval{ $instance = $class->$orig($ops)};

++      if ($@){

++         return $@;

++      }

++      else {

++          return $instance;

++      }

    };

First time I have ever tried to use sometng other that that standard return but I see no reson why it should work ok. I need only give my '30_view.t' test a whirl to see if this works;

ok 1 - DA View is correct

ok 2 - DAS View is correct

ok 3 - Cannot access attribute directly

ok 4 - Cannot change attribute directly

ok 5 - View is Required

not ok 6 - Got error Constructor object

and the last fail was

Can't locate object method "has_errors" via package "Moose::Exception::ValidationFailedForInlineTypeConstraint" at 30_view.t line 103.

so not 100% right yet as I am not getting a 'AllError' class back so I had a quick peek below the hood I see what I was getting and it was a 'Moose::Exception::ValidationFailedForInlineTypeConstrain'. To fix this and get my my test to work again I tried this;

        if ($@){

--          return $@;

++          die $@;

         }

         else {

             return $instance;

         }

as I want to die with my ''MooseX::Constructor::AllErrors' all I was getting before was the first error on the stack.

After that little change all my tests passed so far so good but I thing this test should be added;

like(

    exception {$da = Database::Accessor->new({}); },

    qr /Attribute \(elements\) is required/,

    "Proper scalar error on empty build"

);

what I am checking for is that I have not changed how excelptions work when I do not wrap the 'new' call with an 'eval'. I am basically asking for the 'scalar' value of '$@'. On my test run I get

...

ok 10 - View: param alias fails

ok 11 - Proper scalar error on empty build

Looking good! Now to build an better error-message but that is a story for tomorrow.