[Sqlalchemy-tickets] Issue #3589: Timestamp column syntax error in migration (zzzeek/sqlalchemy)

[Greg S. <iss...@bi...>]

New issue 3589: Timestamp column syntax error in migration
https://bitbucket.org/zzzeek/sqlalchemy/issues/3589/timestamp-column-syntax-error-in-migration

Greg Selvin:

I have a Model class with the database column:
    date_created = db.Column(db.DateTime, default=datetime.utcnow)

this generates the following code in my xxx_migrations.py code:
    Column('date_created', DateTime, default=ColumnDefault(<function ColumnDefault._maybe_wrap_callable.<locals>.<lambda> at 0x1045b22f0>))

Here is the code I borrowed for my db_migrate.py script:

```
#!python

import imp
from migrate.versioning import api
from app import db
from config import SQLALCHEMY_DATABASE_URI
from config import SQLALCHEMY_MIGRATE_REPO

v = api.db_version(SQLALCHEMY_DATABASE_URI, SQLALCHEMY_MIGRATE_REPO)
migration = SQLALCHEMY_MIGRATE_REPO + ('/versions/%03d_migration.py' % (v+1))
tmp_module = imp.new_module('old_model')
old_model = api.create_model(SQLALCHEMY_DATABASE_URI, SQLALCHEMY_MIGRATE_REPO)
exec(old_model, tmp_module.__dict__)
script = api.make_update_script_for_model(SQLALCHEMY_DATABASE_URI, SQLALCHEMY_MIGRATE_REPO, tmp_module.meta, db.metadata)
open(migration, "wt").write(script)
api.upgrade(SQLALCHEMY_DATABASE_URI, SQLALCHEMY_MIGRATE_REPO)
v = api.db_version(SQLALCHEMY_DATABASE_URI, SQLALCHEMY_MIGRATE_REPO)
print('New migration saved as ' + migration)
print('Current database version: ' + str(v))
```

I'm using SQLAlchemy 1.0.9 and Flask-SQLAlchemy 2.1.  I don't think it matters, but I'm using a PostgreSQL 9.4 database.

Any idea what I'm doing wrong here?