when executing the following code in Jupyter, an exception is silently caught by the ROOT kernel and the code ends with a segmentation fault. When running the same code from the ROOT application, the message of the caught exception is displayed, as you can see in the transcript of the code execution below.
root  ROOT::RDataFrame rd(10);
root  h = *rd.Histo1D(“foo”);
Error in TRint::HandleTermInput(): std::runtime_error caught: Unknown column: foo
root  h.Draw()
*** Break *** segmentation violation
Without the exception message it’s difficult to identify the problem is less trivial similar cases, where the user made a typo in the column name.
I’ve attached the screenshot of the code execution in Jupyter,
Is there an option to enable the display of the exception error or to disable the catching ?
Let me know if I should open a JIRA bug report: I see two problems: the message that is not displayed and the undefined state of the variable h, that leads to a segmentation violation later in the code.
I’ve tested the code snippet with ROOT built on Debian from the git tag v6-19-02 for both root application and Jupyter and also for Jupyter with the ROOT release currently used by SWAN (6.18/00). I will test it with 6.20.00 as soon I have installed it.