get_db_prep_lookup call get_prep_value twice for each value if prepared == False

[homm]

In db.models.fields.Field get_db_prep_lookup() check if value is prepared and prepare it:

def get_db_prep_lookup(self, lookup_type, value, connection, prepared=False):
    "Returns field's value prepared for database lookup."
    if not prepared:
        value = self.get_prep_lookup(lookup_type, value)

get_prep_lookup() call get_prep_value() for every value.

But look next:

elif lookup_type in ('exact', 'gt', 'gte', 'lt', 'lte'):
    return [self.get_db_prep_value(value, connection=connection, prepared=prepared)]
elif lookup_type in ('range', 'in'):
    return [self.get_db_prep_value(v, connection=connection, prepared=prepared) for v in value]

Prepared flag not changed and get_db_prep_value() call get_prep_value() through get_db_prep_value() again!

I think get_db_prep_lookup() should call get_db_prep_value() always with prepared == True.

elif lookup_type in ('exact', 'gt', 'gte', 'lt', 'lte'):
    return [self.get_db_prep_value(value, connection=connection, prepared=True)]
elif lookup_type in ('range', 'in'):
    return [self.get_db_prep_value(v, connection=connection, prepared=True) for v in value]

This bug is still unnoticed because in standard ORM get_db_prep_lookup() always calls with prepared == True.

[Aram Dulyan]

Fix with a regression test.

[Łukasz Rekucki]

Patch doesn't apply cleanly, will try to rebase.