Re: Plans for 2.8

On 04/10/18, Daniele Varrazzo (daniele(dot)varrazzo(at)gmail(dot)com) wrote:
> The feature I'm the most excited about (and worried about its
> reception) is to raise a different exception for every postgres error
> message (see #682) . For instance `SELECT * FROM wrong_name` will
> raise `UndefinedTable` rather than `ProgrammingError`. Currently
> handling a specific exception requires catching a broader class and
> looking at the pgcode:
>
> try:
> cur.execute("lock table %s in access exclusive mode nowait" % name)
> except psycopg2.OperationalError as e:
> if e.pgcode == psycopg2.errorcodes.LOCK_NOT_AVAILABLE:
> locked = True
> else:
> raise
>
> This can become a much more natural:
>
> try:
> cur.execute("lock table %s in access exclusive mode nowait" % name)
> except psycopg2.errors.LockNotAvailable:
> locked = True
>
> The error classes are generated automatically from Postgres source
> code and are subclasses of the previously existing ones, so existing
> code should be unaffected. I'd be happy to have input about the
> feature and suggestions before releasing it.

Hi Daniele

The greater depth of exception reporting looks great to me, particularly
if they are subclasses of the existing ones.

Regards
Rory