Make proc-macro bidirectional calls cancellation safe #21410
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| fn handle_failure(failure: Result<bidirectional::SubResponse, ProcMacroClientError>) -> ! { | ||
| match failure { | ||
| Err(ProcMacroClientError::Cancelled { reason }) => { | ||
| panic_any(ProcMacroCancelMarker { reason }); |
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| panic_any(ProcMacroCancelMarker { reason }); | |
| resume_unwind(ProcMacroCancelMarker { reason }); |
There is no need to incur the panic handler in this case
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Here we are not continuing an existing panic. If something goes wrong on the client side, we catch the panic there and convert it into a cancellation message. Up to this point, there is no panic on the server side. We then intentionally originate a new panic here with a marker, which is later caught at the thread join boundary.
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Veykril
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Catch panics in subrequest callbacks, reply with Cancel, and propagate cancellation to the proc-macro server