We’re using ROOT 5.18.00c on red hat 9 linux. I thought I had sent this post out a couple of days ago - but it appears to me that I did not (which is probably a good thing, as it was poorly written)…
We have an abstract class which does not derive from TObject. We do not use ClassDef with this class, though I had seen reference to possibly using ClassDef(className, 0) in this case. I’ll call this class A.
We have a number of classes which derive from class A and TObject.
When we write data, I see class A included with the TStreamerInfo in our output files.
However, I have some colleagues (and I cannot reproduce this) who merge two such files together using hadd, and the resulting file’s TStreamerInfo seems to have had class A’s description stripped. I have looked over their files, and indeed class A is missing from the TStreamerInfo.
When I run hadd - my output file does not have this problem. I am looking to get more information for my colleagues to determine what might be different about our set up. One oddity I see in my run of hadd, is this message after hadd has completed:
Unknown object type, name: TObject title: Basic ROOT object
Is anyone aware of such a situation or possible explanation for what might be going wrong with maintaining the full TStreamerInfo in this case?