[Dbix-class] updated release has broken my code

Thu Jan 21 16:45:14 GMT 2016

I have a little more information now. It appears that the new version is 
checking against the columns of the underlying table from which the 
particular record happens to have been selected, rather than the columns 
of the virtual view. Since the columns have been renamed using AS in the 
SQL, that doesn't work, and in the case of this particular column, it is 
defined as a literal in the SQL anyway and doesn't exist in any 
underlying table.

That new behaviour seems broken in my use case, but I certainly don't 
understand enough about the other use cases that this change was 
designed to support to even begin to suggest how it might be fixed. In 
my case, it needs to check column definitions against those declared in 
my [virtual view] class, not against the columns in the underlying 
tables, which could be anything.

Should I file a bug report? I don't [yet] have a simple test case.

Apologies for top posting, it seems that this post sort of starts a new 
conversation, connected with my problem which is described just below.

Cheers, Dave

On 2016-01-21 11:03, Dave Howorth wrote:
>
>
> On 2016-01-20 18:21, Lasse Makholm wrote:
>> On Wed, Jan 20, 2016 at 4:32 PM, Dave Howorth 
>> <dhoworth at mrc-lmb.cam.ac.uk>
>> wrote:
>>
>>> I have various applications that use DBIx::Class. I just moved one of
>>> them, which has been running OK for quite a while, to a new machine and
>>> that meant it got a new environment, including an updated 
>>> DBIx::Class. It
>>> no longer runs, and it would help me to try to understand what is 
>>> broken in
>>> my own code if I could understand how the DBIC code works and why it 
>>> was
>>> changed. If anybody could give me any pointers, I'd be grateful.
>>>
>>> My code is dying with the error message:
>>>
>>> DBIx::Class::Row::store_column(): No such column '_type' on
>>> TDB::Schema::Result::Node
>>>
>>> This appears to be caused by a change in the code in 
>>> DBIx::Class::Row in
>>> store_column() in particular where
>>>
>>>    $self->throw_exception( "No such column '${column}'" )
>>>      unless exists $self->{_column_data}{$column} ||
>>> $self->has_column($column);
>>>
>>> has been replaced by
>>>
>>>    $self->throw_exception( "No such column '${column}' on " . ref 
>>> $self )
>>>      unless exists $self->{_column_data}{$column} ||
>>> $self->result_source->has_column($column);
>>>
>>> If I put back the original code there, my application appears to work.
>>>
>>> Now my TDB::Schema::Result::Node contains some gnarly code that it will
>>> take me some time to regain familiarity with, and I think it would 
>>> help me
>>> if I understood why that change had been made in DBIx::Class::Row so I
>>> might get some idea of what I need to change in my own code.
>>>
>>> If anybody can point me to the change or provide any explanation, I'd
>>> appreciate it.
>>>
>> https://github.com/dbsrgits/dbix-class/commit/4006691d207a6c257012c4b9a07d674b211349b0 
>>
>>
>> Without knowing what I'm talking about, this would seem to only 
>> matter if
>> you do something funky like dynamically re-blessing result objects...
>>
>> Does TDB::Schema::Result::Node and the underlying table actually have a
>> _type column?
>>
>> /L
>
> Many thanks Lasse,
>
> The class is a virtual view. It's data comes from a union over a bunch 
> of tables but yes it does have a _type column.
>
> I've reproduced the commit log entry below. I obviously haven't had 
> enough coffee this morning because I still haven't worked out what an 
> 'rsrc' is. And sadly I don't understand how the whole view/result 
> source/result/row thing is implemented. I haven't found anything in 
> the POD yet that shows me what I may have done wrong, so I guess I 
> have some careful reading and code reading to come. I've reproduced 
> the relevant bits of the class below as well in case anybody can spot 
> a missing call or bad arguments etc.
>
> Cheers, Dave
>
> Avoid ResultSourceProxy calls whenever possible
>
> Along with efficiency gains this commit makes a very subtle but crucially
> important change: From here now on when we operate on an instance, we are
> guaranteed to query this instance's result source. The previous codepaths
> would nearly randomly switch between the current rsrc instance and the 
> one
> registered with the corresponding result class.
>
>
>
> package TDB::Schema::Result::Node;
>
> use parent 'DBIx::Class::Core';
>
> __PACKAGE__->table_class('DBIx::Class::ResultSource::View');
>
> __PACKAGE__->table('nodes');
> __PACKAGE__->result_source_instance->is_virtual(1);
>
> my $test_db_view =
>    "SELECT
>         sp_id AS id,
>         sp_name    COLLATE latin1_general_ci AS _name,
>         sp_comment COLLATE latin1_general_ci AS _comment,
>         sp_status  COLLATE latin1_general_ci AS status,
>         'species'  COLLATE latin1_general_ci AS _type,
>         old_sp_id  AS old_sunid,
>         pr_id      AS parent_id
>         FROM species
>     UNION ALL
> ... other similar selects for other tables ...
> ";
>
> __PACKAGE__->result_source_instance->view_definition($test_db_view);
>
> __PACKAGE__->add_columns(
>     id => {
>         data_type   => 'mediumint',
>         is_nullable => 0,
>     },
> ... other columns ...
>     _type => {
>         data_type   => 'text',
>         is_nullable => 0,
>     },
> );
>
> __PACKAGE__->set_primary_key('id');
>
>
>>
>>> Cheers, Dave
>>>
>>> PS The old version says it is  '0.08200' and the new is '0.082820'.
>>>
>>> _______________________________________________
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>>> Searchable Archive:
>>> http://www.grokbase.com/group/dbix-class@lists.scsys.co.uk
>>>
>>
>>
>> _______________________________________________
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>> IRC: irc.perl.org#dbix-class
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>> Searchable Archive: 
>> http://www.grokbase.com/group/dbix-class@lists.scsys.co.uk
>
>
> _______________________________________________
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> Searchable Archive: 
> http://www.grokbase.com/group/dbix-class@lists.scsys.co.uk
>