cubicweb #9720390 cubicweb < 3.21 broken by yams >= 0.42 [validation pending]

Traceback (most recent call last):
File "/usr/lib/python2.7/dist-packages/logilab/common/pytest.py", line 443, in testfile
options=self.options, outstream=sys.stderr)
File "/usr/lib/python2.7/dist-packages/logilab/common/pytest.py", line 759, in __init__
testLoader=NonStrictTestLoader())
File "/usr/lib/python2.7/unittest/main.py", line 77, in __init__
self.module = __import__(module)
File "unittest_schema.py", line 33, in <module>
from cubicweb.schema import (
File "/opt/local/dlaxalde/cubicweb/.tox/cubicweb/local/lib/python2.7/site-packages/cubicweb/schema.py", line 39, in <module>
from yams.reader import (CONSTRAINTS, PyFileReader, SchemaLoader,
ImportError: cannot import name obsolete

Yams declares the breaks for cubicweb < 3.21 in debian/control but there's nothing in __pkginfo__.py so that cubicweb 3.20 (at least) is unusable if installed by pip as the latter would pull the latest yams by default.

prioritynormal
typebug
done in3.20.13
load0.500
load left0.000
closed by#9c0fac5028c0 [pkg] Yams >= 0.42 breaks CubicWeb < 3.21
patch[pkg] Yams >= 0.42 breaks CubicWeb < 3.21 [applied]