Hi Kenton, I am encountering a problem where capabilities acting as views over some resources are intermittently causing segfaults. The capability is wrapped using *capnp::membrane* given a membrane policy where the promise returned by *onRevoked* can be rejected on-demand via a synchronous reject function (a kj::PromiseFulfillerPair is used to do this).
The resources may be destroyed together at any time, whereby the membrane managing the capabilities accessing the resource states is revoked. However, this does not seem to be an instantaneous operation (presumably due to revocation being managed by a promise), and I have encountered the following issue as a result: Unresolved requests made before the membrane policy has been revoked and where the resource has since been destroyed are not cancelled but will rather resolve, accessing invalid memory. The workaround I have found to address this issue is to add a flag and a *kj::Canceller* to the capability implementations whereby new requests are rejected if the flag is set, and in addition when the flag is first set, the canceler cancels all returned promises in cases where a chained promise was returned rather than *kj::READY_NOW*. However, this is very ugly and necessitates keeping around references to the capability implementations before they are converted to *::Client* objects (so that we can set that flag). I'm thinking that surely there has to be a better way I have not considered. Do you have any thoughts on a better solution to this problem? If needed, I can try create a minimal reproducible example to illustrate. In case it matters, OS is Ubuntu 20.04 and capnp version is 8.0.0, both currently contained by my production environment. Thank you for your time, Rowan Reeve -- You received this message because you are subscribed to the Google Groups "Cap'n Proto" group. To unsubscribe from this group and stop receiving emails from it, send an email to capnproto+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/capnproto/cfa7c8a3-bb32-4a01-882a-cc4a6590d23an%40googlegroups.com.
