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process: unregister Windows wait before closing child handle - #8564
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On Windows, `tokio::process::imp::Child` previously declared `child: StdChild` before `waiting: Option<Waiting>`. Because Rust drops struct fields in declaration order, dropping a `Child` with an active wait registration closed the underlying process handle in `StdChild::drop` before `Waiting::drop` called `UnregisterWaitEx`, violating the Win32 `RegisterWaitForSingleObject` contract. Reorder the fields of `Child` so that `waiting` is dropped before `child`, ensuring `UnregisterWaitEx` completes before `StdChild` closes the process handle. Fixes: tokio-rs#8563
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Fix looks correct to me. Will this be forward-ported? master still has the old field order.
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On Windows,
tokio::process::imp::Childpreviously declaredchild: StdChildbeforewaiting: Option<Waiting>. Because Rust drops struct fields in declaration order, dropping aChildwith an active wait registration closed the underlying process handle inStdChild::dropbeforeWaiting::dropcalledUnregisterWaitEx, violating the Win32RegisterWaitForSingleObjectcontract.Reorder the fields of
Childso thatwaitingis dropped beforechild, ensuringUnregisterWaitExcompletes beforeStdChildcloses the process handle.Fixes: #8563