No error raised when a method depends on Parameterized instances set after calling super() #566
Description
See this example taken from Panel's user guide. The two objects must be declared in the __init__ before calling super().
class P2(param.Parameterized):
value = param.String()
class P1(param.Parameterized):
def __init__(self, **params):
# Works as expected when declared before
# self.p2 = P2()
super().__init__(**params)
# Does not work when declared after super()
# Raises an error in param<1.12, nothing for param 1.12
self.p2 = P2()
@param.depends('p2.value', watch=True)
def cb(self):
print('fired')When they're declared after as in the example above, the following error used to be raised (this is param 1.11.1):
--------------------------------------------------------------------------
AttributeError Traceback (most recent call last)
<ipython-input-36-7e8d061f6e7f> in <module>
----> 1 p1 = P1()
<ipython-input-35-d76ac1c5846c> in __init__(self, **params)
6 def __init__(self, **params):
7 # self.p2 = P2()
----> 8 super().__init__(**params)
9 self.p2 = P2()
10
~/miniconda3/envs/holoviz37/lib/python3.7/site-packages/param/parameterized.py in __init__(self, **params)
2610 # 'dependers'.
2611 grouped = defaultdict(list)
-> 2612 for dep in self.param.params_depended_on(n):
2613 grouped[(id(dep.inst),id(dep.cls),dep.what)].append(dep)
2614 for group in grouped.values():
~/miniconda3/envs/holoviz37/lib/python3.7/site-packages/param/parameterized.py in params_depended_on(self_, name)
1858
1859 def params_depended_on(self_,name):
-> 1860 return _params_depended_on(MInfo(cls=self_.cls,inst=self_.self,name=name,method=getattr(self_.self_or_cls,name)))
1861
1862
~/miniconda3/envs/holoviz37/lib/python3.7/site-packages/param/parameterized.py in _params_depended_on(minfo)
500 dinfo = getattr(minfo.method,"_dinfo", {})
501 for d in dinfo.get('dependencies', list(minfo.cls.param)):
--> 502 things = (minfo.inst or minfo.cls).param._spec_to_obj(d)
503 for thing in things:
504 if isinstance(thing,PInfo):
~/miniconda3/envs/holoviz37/lib/python3.7/site-packages/param/parameterized.py in _spec_to_obj(self_, spec)
1902 attr = m.group("attr")
1903
-> 1904 src = self_.self_or_cls if obj=='' else _getattrr(self_.self_or_cls,obj[1::])
1905 cls,inst = (src, None) if isinstance(src, type) else (type(src), src)
1906
~/miniconda3/envs/holoviz37/lib/python3.7/site-packages/param/parameterized.py in _getattrr(obj, attr, *args)
281 def _getattr(obj, attr):
282 return getattr(obj, attr, *args)
--> 283 return reduce(_getattr, [obj] + attr.split('.'))
284
285
~/miniconda3/envs/holoviz37/lib/python3.7/site-packages/param/parameterized.py in _getattr(obj, attr)
280 def _getattrr(obj, attr, *args):
281 def _getattr(obj, attr):
--> 282 return getattr(obj, attr, *args)
283 return reduce(_getattr, [obj] + attr.split('.'))
284
AttributeError: 'P1' object has no attribute 'p2'Even though it's an error message that's quite hard to understand, at least there was an error. The current version on master doesn't raise any.