Attached I have a root file. Try running MakeProxy on the CollectionTree TTree. It basically contains a TTree with two leaves, each leaf is an unsplit class (the new style in ATLAS). Unfortunately, when I run MakeProxy in it, it can’t sort out the details and gives me a .h file that isn’t useful. MakeSelector gives the same problem. The classes are custom classes, but they are simple structs.
TBrowser can look inside these classes and plot them just fine, however. So it seems like the streamer information is there and just fine. If these classes are split (as they used to be) then ROOT works just fine. And it looks like MakeClass can’t deal with these files either.
Am I stuck, or is this something funny going on in ROOT? I did my testing in 5.34.04. Attached is a 200KB file with a few events in CollectionTree, which is the important one.
full-mcfile.root (223 KB)