[issue34433] cancel all other pending child futures

Change by tzongw : -- keywords: +patch pull_requests: +8298 stage: -> patch review ___ Python tracker <https://bugs.python.org/issue34433> ___ ___ Python-

[issue34433] cancel all other pending child futures

New submission from tzongw : In `tasks.gather`, when a child future throws an exception and `return_exceptions` is False, outer future will call `set_exception` while other child futures is still running. In this case, outer future call `_GatheringFuture.cancel' first to cancel all other