Re: [Sqlalchemy-tickets] [sqlalchemy] #1458: improve quality of error message when attempting to get an object from a multi-column-primary-key without sufficient elements

[sqlalchemy <mi...@zz...>]

#1458: improve quality of error message when attempting to get an object from a
multi-column-primary-key without sufficient elements
--------------------------------+-------------------------------------------
    Reporter:  phrrngtn         |       Owner:  zzzeek               
        Type:  enhancement      |      Status:  new                  
    Priority:  low              |   Milestone:                       
   Component:  (none)           |    Severity:  trivial - <10 minutes
  Resolution:                   |    Keywords:                       
Status_field:  awaiting triage  |  
--------------------------------+-------------------------------------------
Old description:

> sqlalchemy/orm/query.py:
>             mapper = q._mapper_zero()
>             params = {}
>             (_get_clause, _get_params) = mapper._get_clause
>
>             _get_clause = q._adapt_clause(_get_clause, True, False)
>             q._criterion = _get_clause
>
>             for i, primary_key in enumerate(mapper.primary_key):
>                 try:
>                     params[_get_params[primary_key].key] = ident[i]
>                 except IndexError:
>                     raise sa_exc.InvalidRequestError("Could not find
> enough values to formulate primary key for "
> -                        "query.get(); primary key columns are %s" % ',
> '.join("'%s'" % c for c in q.mapper.primary_key))
> +                        "query.get(); primary key columns are %s" % ',
> '.join("'%s'" % c for c in mapper.primary_key))

New description:

 change is obvious from the diff. If one has a table with a multi-column
 primary key and you attempt to do a session.get(i) (i.e. pass in a scalar)
 or session.get((i,)) (i.e. pass in a tuple of the wrong length), the
 exception fails with an AttributeError (our session is instantiated with
 query_cls=CachingQuery but a similar error occurs in the distributed
 sqlalchemy)

    "query.get(); primary key columns are %s" % ', '.join("'%s'" % c for c
 in q.mapper.primary_key))
 AttributeError: 'CachingQuery' object has no attribute 'mapper'

-- 
Ticket URL: <http://www.sqlalchemy.org/trac/ticket/1458#comment:1>
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