Unique attributes are lazy loaded

[gabriel-ilie]

python2.7
pony orm 0.7.10

---

from pony.orm import *
db = Database()

class A(db.Entity):
name=Required(str, unique=True)
b = Set('B')

class B(db.Entity):
x = Required(str)
a = Required('A')

db.bind('sqlite', ':memory:')
db.generate_mapping(create_tables=True)

with db_session:
a = A(name='name')
b = B(a=a, x='x')

with db_session:
b = B.get(x='x')
#b.a.load()
b.a.name = 'sss'

====================>
Traceback (most recent call last):
File "/mnt/hgfs/share/pony_orm_unique_keys_not_loaded.py", line 22, in
b.a.name = 'sss'
File "/usr/local/lib/python2.7/dist-packages/pony/orm/core.py", line 2357, in set
for undo_func in reversed(undo_funcs): undo_func()
File "/usr/local/lib/python2.7/dist-packages/pony/orm/core.py", line 2323, in undo_func
if old_val is NOT_LOADED: obj.vals.pop(attr)
KeyError: A.name

If I uncomment << b.a.load() >> everything works as expected;
If I use << b.a.set(name='sss') >> everything works as expected.
If I make name attribute not unique everything works as expected.
If I specify lazy=False for name it is still lazy loaded.

[ChiliConSql]

I am having the same issue.
python 3.7
pony 0.7.10

any suggestions?