chore: port upstream generator fix (FIR-17479)#5
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Summary:
Exceptions from a nested generator are to be re-thrown by `yield_value(Generator&)::awaitable::await_resume`.
Unfortunately, `yield_value(Generator&)` has a micro-optimization to avoid suspending when the child generator is ready upon beginning (empty or error). The optimization failed to check for exceptions:
- on exception `is_completed()` is true
- so we would fall through to `awaitable{nullptr}`
- which makes no provisions for re-throwing, so the behavior was as if the child generator was empty
Reviewed By: dmm-fb
Differential Revision: D50708988
fbshipit-source-id: 7213b4e28d210c28aa19e4d850481af416e30279
freitmi
approved these changes
Dec 4, 2025
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Port of facebook@f4f3175
We are using generators more and more -- seems prudent to port upstream fixes.
Summary:
Exceptions from a nested generator are to be re-thrown by
yield_value(Generator&)::awaitable::await_resume.Unfortunately,
yield_value(Generator&)has a micro-optimization to avoid suspending when the child generator is ready upon beginning (empty or error). The optimization failed to check for exceptions:is_completed()is trueawaitable{nullptr}Reviewed By: dmm-fb
Differential Revision: D50708988
fbshipit-source-id: 7213b4e28d210c28aa19e4d850481af416e30279