On Thu, 19 Nov 2020 at 15:42, Patrick Starrenburg <patrick.starrenb...@gmail.com> wrote:
> I am using psycopg2 in a Django app. In my code I am checking for various > exceptions, one of which is foreign key violations. > > I see in the psycopg2 docs https://www.psycopg.org/docs/errors.html that > ForeignKeyViolation > is under the base IntegrityError exception. I would like to be able to > specifically catch, and respond to the ForeignKeyViolation error. I am coding > using the recommendation in the docs (below). > > It is working (a forced FK violation is specifically caught) my question is > though that in my IDE (PyCharm) it reports that it cannot find the reference > 'errors' and I cannot use dotted links to drill down to the > errors.ForeignKeyViolation function. > > I can type psycopg2.IntegrityError and reference to it is found (and I see > that it is listed in the __init.py__ file). > > When I Google this some say it is a PyCharm bug, some say that PyCharm is > following the Python package convention. Yes, it is a PyCharm shortcoming: the exception is there: >>> import psycopg2.errors >>> psycopg2.errors.ForeignKeyViolation psycopg2.errors.ForeignKeyViolation The exceptions are defined in the C module, but they are exposed in the errors module. If you look at the source code for the module, it appears mostly empty: the exceptions are added there when the psycopg2._psycopg internal module is imported. Personally this is good enough: the module works as expected for all Python code; supporting PyCharm is not mandatory as far as I'm concerned. I am happy to receive patches to make PyCharm work better, but working on it myself isn't my priority now. -- Daniele
