[ntuple] don't try to construct an Emulated TClass as a RClassField #17661
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When constructing a RClassField we need some information that we don't have when the TClass is Emulated (or less), therefore we now check that we have at least an Interpreted TClass in RFieldBase::Create(). If not, we follow the same logic as when we have no TClass at all (i.e. either create an emulated field or fail, depending on the user options).
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Test Results 18 files 18 suites 4d 4h 0m 58s ⏱️ For more details on these failures, see this check. Results for commit 6c10350. |
| @@ -594,7 +594,10 @@ ROOT::Experimental::RFieldBase::Create(const std::string &fieldName, const std:: | |||
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| if (!result) { | |||
| auto cl = TClass::GetClass(canonicalType.c_str()); | |||
| if (cl != nullptr) { | |||
| // NOTE: if the class is not at least "Interpreted" we don't have enough information to | |||
| // properly construct the RClassField (e.g. we are missing the list of bases), so in that | |||
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This is not precise. The list of base class is available in the TStreamerInfo and thus available for an Emulated class.
Is this PR a temporary fix/workaround or am I missing something?
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How do you access that information? When we load a class from file without dictionary we observe that TClass::GetListOfBases() returns nullptr. Do we need to take some explicit steps to have that list filled? Or do we need to call a different method?
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You have to look at the TStreamerInfo, eg.
auto info = cl->GetStreamerInfo(); // This return the current StreamerInfo describing the in memory layout
for(auto elem : TRangeStaticCast<TStreamerElement>( *info )) {
if (elem->IsBase()) {
...
}
}
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@pcanal I guess you meant TRangeStaticCast<TStreamerElement>(info->GetElements());
but this gives me TStreamerElements and TStreamerBases: how do I get to the TBaseClass from there?
Or can I still access stuff like GetDelta() from a TStreamerBase?
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I guess you meant TRangeStaticCast(info->GetElements());
Indeed, sorry :)
how do I get to the TBaseClass from there?
You can't, it is a different interface.
Or can I still access stuff like GetDelta() from a TStreamerBase?
Yes, through GetOffset. Note that the list of TStreamerElement will only contains the direct base classes.
When constructing a RClassField we need some information that we don't have when the TClass is Emulated (or less), therefore we now check that we have at least an Interpreted TClass in RFieldBase::Create(). If not, we follow the same logic as when we have no TClass at all (i.e. either create an emulated field or fail, depending on the user options).
Checklist:
This PR fixes #17648