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Date: Fri, 11 Feb 2022 20:42:34 +0100
From: Paolo De Stefani <paolo@paolodestefani.it>
To: Daniele Varrazzo <daniele.varrazzo@gmail.com>
Cc: Psycopg <psycopg@postgresql.org>
Subject: Re: exception psycopg.Error from psycopg2 to psycopg 3
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Yes perfect solution for me
Thank your the lightspeed response..

Il 11/02/2022 19:47 Daniele Varrazzo ha scritto:
> On Fri, 11 Feb 2022 at 18:34, Paolo De Stefani 
> <paolo@paolodestefani.it> wrote:
> 
> Hi Paolo,
> 
> Yes, I can see some inconsistency there. At the moment I suggest you
> use `e.diag.sqlstate`, which works as expected and is available in
> psycopg2 too.
> 
>     In [8]: try: cnn.execute("""
>       ...: do $$
>       ...: begin
>       ...: RAISE EXCEPTION 'Error wrong database' USING HINT = 'You
> need to use a different database', ERRCODE = 'PA002';
>       ...: end$$
>       ...: language plpgsql
>       ...: """)
>       ...: except Exception as e: ex = e
> 
>     In [10]: ex.diag.sqlstate
>     Out[10]: 'PA002'
> 
>     In [11]: ex.sqlstate
>     None
> 
> What is happening is that, in psycopg 3, Error.sqlstate is a class
> property and is only set for the known classes - the ones listed at
> <https://www.psycopg.org/psycopg3/docs/api/errors.html#sqlstate-exceptions>.
> 
> The attribute `e.diag.sqlstate` instead comes from the error message
> received from the server. When the error is received, the matching
> class is looked up by sqlstate, with the basic dbapi exceptions as
> fallback if the code is not known, and the server result is passed to
> the exception state, so that `e.diag` is populated with all the
> details (such as the message, the hint etc).
> 
> The cases I had in mind where 1) known exceptions where Error.sqlstate
> and e.diag.sqlstate would match, and 2) non-server exceptions (e.g. on
> connection, or raised by Python code) where Error.sqlstate and
> e.diag.sqlstate are both None.
> 
> I didn't think about the case 3) where a sqlstate exists, but psycopg
> doesn't know it. In this case, the result of the current
> implementation is to raise an exception with the sqlstate left to None
> on the class but available in diag.
> 
> ISTM that setting e.sqlstate = e.diag.sqlstate would be an
> improvement. The docs describe indeed that sqlstate is expected to be
> None on the DBAPI classes
> (https://www.psycopg.org/psycopg3/docs/api/errors.html#psycopg.Error.sqlstate)
> but that wasn't written thinking about the inconsistency above. It
> makes more sense that Error.sqlstate is whatever state received, if
> any.
> 
> Does it sound right?
> 
> -- Daniele

-- 
Paolo De Stefani