Error message for table names > 50 characters is very poor.

[Steve Lacy]

If you try to create a model with a table name > 50 characters (and you've enabled django.contrib.auth) then you get a very poor error message when running syncdb.

For example:

env src/tmp/qdel$ python ./manage.py syncdb
Creating tables ...
Traceback (most recent call last):
  File "./manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "/home/slacy/src/tmp/env/local/lib/python2.7/site-packages/django/core/management/__init__.py", line 443, in execute_from_command_line
    utility.execute()
  File "/home/slacy/src/tmp/env/local/lib/python2.7/site-packages/django/core/management/__init__.py", line 382, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/home/slacy/src/tmp/env/local/lib/python2.7/site-packages/django/core/management/base.py", line 196, in run_from_argv
    self.execute(*args, **options.__dict__)
  File "/home/slacy/src/tmp/env/local/lib/python2.7/site-packages/django/core/management/base.py", line 232, in execute
    output = self.handle(*args, **options)
  File "/home/slacy/src/tmp/env/local/lib/python2.7/site-packages/django/core/management/base.py", line 371, in handle
    return self.handle_noargs(**options)
  File "/home/slacy/src/tmp/env/local/lib/python2.7/site-packages/django/core/management/commands/syncdb.py", line 110, in handle_noargs
    emit_post_sync_signal(created_models, verbosity, interactive, db)
  File "/home/slacy/src/tmp/env/local/lib/python2.7/site-packages/django/core/management/sql.py", line 189, in emit_post_sync_signal
    interactive=interactive, db=db)
  File "/home/slacy/src/tmp/env/local/lib/python2.7/site-packages/django/dispatch/dispatcher.py", line 172, in send
    response = receiver(signal=self, sender=sender, **named)
  File "/home/slacy/src/tmp/env/local/lib/python2.7/site-packages/django/contrib/auth/management/__init__.py", line 54, in create_permissions
    auth_app.Permission.objects.bulk_create(objs)
  File "/home/slacy/src/tmp/env/local/lib/python2.7/site-packages/django/db/models/manager.py", line 140, in bulk_create
    return self.get_query_set().bulk_create(*args, **kwargs)
  File "/home/slacy/src/tmp/env/local/lib/python2.7/site-packages/django/db/models/query.py", line 416, in bulk_create
    self.model._base_manager._insert(objs_without_pk, fields=[f for f in fields if not isinstance(f, AutoField)], using=self.db)
  File "/home/slacy/src/tmp/env/local/lib/python2.7/site-packages/django/db/models/manager.py", line 203, in _insert
    return insert_query(self.model, objs, fields, **kwargs)
  File "/home/slacy/src/tmp/env/local/lib/python2.7/site-packages/django/db/models/query.py", line 1576, in insert_query
    return query.get_compiler(using=using).execute_sql(return_id)
  File "/home/slacy/src/tmp/env/local/lib/python2.7/site-packages/django/db/models/sql/compiler.py", line 910, in execute_sql
    cursor.execute(sql, params)
  File "/home/slacy/src/tmp/env/local/lib/python2.7/site-packages/django/db/backends/util.py", line 40, in execute
    return self.cursor.execute(sql, params)
  File "/home/slacy/src/tmp/env/local/lib/python2.7/site-packages/django/db/backends/postgresql_psycopg2/base.py", line 52, in execute
    return self.cursor.execute(query, args)
django.db.utils.DatabaseError: value too long for type character varying(50)

• Doesn't tell me which model
• Doesn't say "generated table name is too long"
• Works if django.contrib.auth isn't in INSTALLED_APPS, fails otherwise.
• Can fail if model name < 50 characters when the app name is long. (since table name is concatenation of app & model class names)

I'd guess that the solution is to catch the DatabaseError in contrib/auth/management/init.py create_permissions() and log some useful message there then re-raise.

[Simon Charette]

Duplicate of #17763.

[Simon Charette]

After a second thought I think it might be worth it to display a more meaningful error message, as proposed, until #17763 is fixed since it might take a while for native migration to land.

I agree that the actual error message is quite confusing, it wouldn't hurt to explain the limitation.

Re-opening as DDN.

[rasca]

Related to #18866 that tracks the verbose_name errors

[ANUBHAV JOSHI]

As I have understood it worksforme or else if someone can help me reproduce the problem/error if I am wrong, then it would be very helpful.

[Tim Graham]

I tried to reproduce this, but I think it's actually a duplicate of #18866. The auth_permission.name column is limited to 50 characters, but it's based on the verbose_name which is now validated for length < 39 so the permission name won't be too long.