Customize traceback output for ExceptionGroup

[cosminstirbu]

Hello,

In our test we have a little utility function that allows us to run several other functions concurrently. We check if the concurrent functions failed with an exception and then raise an ExceptionGroup containing all these sub-exceptions.

The problem is that when a test fails with an ExceptionGroup the output is too verbose as it contains traceback information about the ExceptionGroup as well which is repetitive and not really useful.

Is there any way to print only the sub-exceptions traceback when a test fails due to an ExceptionGroup?

Setting the --tb argument doesn't really help, because it still prints information about the ExceptionGroup and it also affects tests that fail with regular exceptions.

[jakkdl]

This should be better with #13380 released in 8.4.0

[cosminstirbu]

It's a significant improvement, thank you!