cubicweb-container #3083537 crash on .parent when called with a non-container entity [resolved]

e.g. a CWUser

prioritynormal
typebug
done in2.0.0
load0.100
load left0.000
closed by#96bac7ee096a [entities,test] make sure .parent never crashes
patch[entities,test] make sure .parent never crashes [applied]