CharField max_lenght is not enforced on SQLite backend with Python 3

[lvella]

I am using Django 1.6 with CPython 3.3.2. The minimal test case to show the bug is as follows:

From a Django project using SQLite, create an app:

$ python3 manage.py startapp case

Add the following contents to 'case/models.py':

from django.db import models

class A(models.Model):

b = models.CharField(max_length=10)

def str(self):

return self.b

Then, after adding the app to INSTALLED_APPS setting, sync the database:

$ python3 manage.py syncdb

Then run:
$ python3 manage.py shell

from case.models import A
a = A(b='x'*20)
a.save()
A.objects.all()[0]

<A: xxxxxxxxxxxxxxxxxxxx>

If you could reproduce, the 20 characters string was allowed on a CharField with max_length=10. This caused me problems because I user SQLite on development, and PostgreSQL on production, and because of this issue, I missed a bug during development only to see it in production.

[Tim Graham]

Yes, this is a limitation of SQLite. see ​http://www.sqlite.org/faq.html#q9

This is why it's recommended to use the same database for development as you use in production.

[vivook]

This could be done with a check constraint. [See discussion ​https://forum.djangoproject.com/t/idea-make-sqlite-enforce-varchar-lengths-via-check-constraints/33101]