On Sun, Feb 28, 2021 at 6:17 PM Guido van Rossum email@example.com wrote:
On Sun, Feb 28, 2021 at 2:40 AM Irit Katriel firstname.lastname@example.org wrote:
In earlier versions of the PEP ExceptionGroup was not immutable and split actually removed matching exceptions from it. It was also iterable so you could get a flat list of all the contained leaf exceptions. Then we changed it.
ExceptionGroup is a tree of exceptions, and the internal nodes of the tree (which are ExceptionGroups) have metadata on them - context, cause, traceback. If you want the full traceback of a leaf exception you need to concatenate the tracebacks of all the exceptions on the path from the root to the leaf. If you flatten an ExceptionGroup and create a new list ExceptionGroup(list(eg)) you don't lose metadata (unless eg's tree has depth 1).
Is this a typo? Did you mean "If you flatten [it] and create a new list... you *do* lose metadata (unless ... depth 1)"?
It is a typo, thanks.