Codechange: document/fix virtual function resolving in con/destructors #9257
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…are resolved statically This as during construction the sub class has not been initialized yet, and during destruction the sub class has already been destroyed, so the overriding virtual function would be accessing uninitialized data.
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…tions statically in destructors In the destructors of many of the network related classes Close() is called, just like the top class in that hierarchy. However, due to virtual functions getting resolved statically in the destructor it would always call the empty Close() of the top class. Document the other cases where a virtual call is resolved statically.
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Motivation / Problem
Virtual functions should not be invoked from a constructor or destructor of the same class. Confusingly, virtual functions are resolved statically (not dynamically) in constructors and destructors for the same class. The call should be made explicitly static by qualifying it using the scope resolution operator. https://lgtm.com/rules/2159620519/
Description
Added documentation and the explicit static call where applicable and removed some pointless code. See the commit messages for more details.
Limitations
The problems with the TCPConnecters are not solved as they are simply broken for failure cases when having no threads. #9255 has been made to solve that.
Checklist for review
Some things are not automated, and forgotten often. This list is a reminder for the reviewers.