[Python] Don't call TClass::GetClass() on branch type in TTreePyz
#18604
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It's not clear to me how it can even happen that TClass::GetClass() is `nullptr` for the type of a TTree branch. It looks like the check is superfluous, and by not doing it we can avoid the memory hogging of `GetClass()` for standard vector types. Closes root-project#18524.
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vepadulano
approved these changes
May 5, 2025
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LGTM because the class was already retrieved via branch->GetClassName(). Even in the case where this returns an empty string, it will be practically the same behaviour as before: we would return a pointer and an empty string which would then cause this other part of the code to eventually raise an exception.
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It's not clear to me how it can even happen that TClass::GetClass() is
nullptrfor the type of a TTree branch.It looks like the check is superfluous, and by not doing it we can avoid the memory hogging of
GetClass()for standard vector types.My suspicion is that the
klassvariable was there because many years ago, cppyy used ROOT casting via TClass, which got replaced at some point fromBindRootObjectNoCast( *(char**)branch->GetAddress(), klass )toBindCppObjectNoCast( *(char**)branch->GetAddress(), Cppyy::GetScope( branch->GetClassName() ) )(see commit 9687598). Before that refactor, making the sanity check thatklasswas notnullptrmade sense. But it looks like this is not needed anymore since the casting is done exclusively with cppyy.Closes #18524.