1. Michael Bayer
  2. sqlalchemy
  3. Issues

Issues

Issue #2960 resolved

.pyc file / with_metaclass thing between 0.8/0.9 - needs more detail

jeroen_stevens
created an issue

After updating SQLAlchemy to 0.9.2 i got this error:

Traceback (most recent call last):
  File "/home/vagrant/test/api/app/database/__init__.py", line 1, in <module>
    from sqlalchemy import create_engine
  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/__init__.py", line 50, in <module>
    from .types import (
  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/types.py", line 26, in <module>
    from . import exc, schema, util, processors, events, event
  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/schema.py", line 33, in <module>
    from . import exc, util, dialects, event, events, inspection
  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/event/__init__.py", line 7, in <module>
    from .api import CANCEL, NO_RETVAL, listen, listens_for, remove, contains
  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/event/api.py", line 13, in <module>
    from .base import _registrars
  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/event/base.py", line 152, in <module>
    class Events(util.with_metaclass(_EventMeta, object)):
AttributeError: 'module' object has no attribute 'with_metaclass'

In version 0.8

class Events(util.with_metaclass(_EventMeta, object))

this existed in multiple files and now in 0.9.2 only in the base.py file so I tried to change it to

class Events(object):

That resulted in:

  File "/home/vagrant/shuffler/api/app/database/__init__.py", line 1, in <module>
    from sqlalchemy import create_engine
  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/__init__.py", line 50, in <module>
    from .types import (
  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/types.py", line 26, in <module>
    from . import exc, schema, util, processors, events, event
  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/schema.py", line 33, in <module>
    from . import exc, util, dialects, event, events, inspection
  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/events.py", line 220, in <module>
    class SchemaEventTarget(object):
  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/events.py", line 227, in SchemaEventTarget
    dispatch = event.dispatcher(DDLEvents)
  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/event/base.py", line 209, in __init__
    self.dispatch_cls = events.dispatch
AttributeError: type object 'DDLEvents' has no attribute 'dispatch'

I don't know where to look anymore.

Comments (7)

  1. Michael Bayer repo owner

    OK a little puzzling here is that you're saying the "with_metaclass" thing is in 0.8, which is not the case, that's in 0.9. In 0.8 we have the usual __metaclass__ attribute.

    When I switch the files in place from 0.9 to 0.8 I get this error, until the .pyc files are deleted.

    So it's a little unclear here if you are in fact going from 0.8 to 0.9, or 0.9 back to 0.8 which is where this is observed, but I think what you need to do is just delete the .pyc files.

    if you can confirm this is from 0.9 down to 0.8, not the other way around, I can maybe try to figure out the exact nature of why this happens though people have generally not been reporting it, I think typically using pip/setuptools prevents this kind of thing from happening.

  2. jeroen_stevens reporter

    Sorry for the confusing. Today i updated from 0.8.0 (when everything was fine) to 0.9.2. That is when i got the error. Now i've set it back to 0.8.0 just because I knew that was the latest version it was still working on.

    So I should just delete all the .pyc files from the sqlalchemy directory?

  3. Michael Bayer repo owner

    how are you installing this? SQLA 0.9.2 has the "util.with_metaclass" call, 0.8 does not. you should not get any errors upgrading from 0.8 to 0.9.2. Can you please start with a fresh install of 0.9.2, ensure no .py or .pyc files are present first, then see if 0.9.2 produces an error (and if it does, what is the exact error?)

  4. jeroen_stevens reporter

    just

    sudo pip install SQLAlchemy
    

    Now I uninstalled all versions of SQLAlchemy with:

    sudo pip uninstall SQLAlchemy
    

    followed by:

    sudo pip install SQLAlchemy # (again)
    

    and now everything is just running smoothly again!

    Hmm, there probably went something wrong with the installation the first time when I installed 0.9.2. No idea what it could have been though.

    But many thanks for your support!! Now I can finally continue.

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