Emit all errors in hooks #1806
…rrors using the multi-exception handling on Python 3. Fixes #1770.
Right, so I see
I created this repro, which if run on master, produces:
whereas with the patch applied, the result includes both exceptions that occurred:
I believe this effectively demonstrates the effectiveness of the change.
Because this relies on Python 3 to achieve its ends, I'm not going to attempt to back port this to 17.x, although I welcome others to try.