Django South migration error "contains null values" with null=True field

Question

When adding a field for easy-thumbnails to a model

easy_thumbnail = ThumbnailerImageField(
    null=True, blank=True, verbose_name=_("Easy_Thumbnails"),
    upload_to="easy_thumbnails",
    resize_source=dict(size=(100, 100), crop="smart"),
)

When executing ./manage.py schemamigration test --auto, South produces the following migration:

def forwards(self, orm):
    # Adding field 'Test.easy_thumbnail'
    db.add_column('test_test', 'easy_thumbnail', self.gf('django.db.models.fields.files.ImageField')(), keep_default=False)
[...]
models = {
    'test.test': {
        'Meta': {'object_name': 'Test'},
        'easy_thumbnail': ('django.db.models.fields.files.ImageField', [], {}),

When executing ./manage.py migrate test, I got this error:

The error is `django.db.utils.IntegrityError: column "easy_thumbnail" contains null values`

Answer 1

Modifying the migration script as follows solves the problem:

• Adding "null=True, blank=True" in db.add_column
• Adding "'null': 'True', 'blank': 'True'" in models['test.test']['easy_thumbnail']

The code:

def forwards(self, orm):
    # Adding field 'Test.easy_thumbnail'
    db.add_column('test_test', 'easy_thumbnail', self.gf('django.db.models.fields.files.ImageField')(null=True, blank=True), keep_default=False)
[...]
models = {
    'test.test': {
        'Meta': {'object_name': 'Test'},
        'easy_thumbnail': ('django.db.models.fields.files.ImageField', [], {'null': 'True', 'blank': 'True'}),