Use UnwindDetector to protect against exceptions in all these RPC object desturctors.

c++/src/capnp/rpc.c++

@@ -735,6 +735,7 @@ private:
         : RpcClient(connectionState), importId(importId) {}
 
     ~ImportClient() noexcept(false) {
+      unwindDetector.catchExceptionsIfUnwinding([&]() {
         // Remove self from the import table, if the table is still pointing at us.  (It's possible
         // that another thread attempted to obtain this import just as the destructor started, in
         // which case that other thread will have constructed a new ImportClient and placed it in
@@ -757,6 +758,7 @@ private:
           builder.setReferenceCount(remoteRefcount);
           message->send();
         }
+      });
     }
 
     void addRemoteRef() {
@@ -794,6 +796,8 @@ private:
 
     uint remoteRefcount = 0;
     // Number of times we've received this import from the peer.
+
+    kj::UnwindDetector unwindDetector;
   };
 
   class PipelineClient final: public RpcClient {
@@ -1372,6 +1376,7 @@ private:
     CapInjectorImpl(RpcConnectionState& connectionState)
         : connectionState(connectionState) {}
     ~CapInjectorImpl() noexcept(false) {
+      unwindDetector.catchExceptionsIfUnwinding([&]() {
         kj::Vector<kj::Own<ResolutionChain>> thingsToRelease(exports.size());
 
         if (connectionState.networkException == nullptr) {
@@ -1379,6 +1384,7 @@ private:
             thingsToRelease.add(connectionState.releaseExport(exportId, 1));
           }
         }
+      });
     }
 
     bool hasCaps() {
@@ -1451,6 +1457,8 @@ private:
     kj::Vector<ExportId> exports;
     // IDs of objects exported during finishDescriptors().  These will need to be released later.
 
+    kj::UnwindDetector unwindDetector;
+
     static const void* identity(const rpc::CapDescriptor::Reader& desc) {
       // TODO(cleanup):  Don't rely on internal APIs here.
       return _::PointerHelpers<rpc::CapDescriptor>::getInternalReader(desc).getLocation();
@@ -1471,6 +1479,7 @@ private:
         : connectionState(kj::addRef(connectionState)), id(id), fulfiller(kj::mv(fulfiller)) {}
 
     ~QuestionRef() {
+      unwindDetector.catchExceptionsIfUnwinding([&]() {
         if (connectionState->networkException != nullptr) {
           return;
         }
@@ -1505,6 +1514,7 @@ private:
         } else {
           question.selfRef = nullptr;
         }
+      });
     }
 
     inline QuestionId getId() const { return id; }
@@ -1533,6 +1543,7 @@ private:
     QuestionId id;
     kj::Own<kj::PromiseFulfiller<kj::Promise<kj::Own<RpcResponse>>>> fulfiller;
     kj::Maybe<kj::Own<CapExtractorImpl>> resultCaps;
+    kj::UnwindDetector unwindDetector;
   };
 
   class RpcRequest final: public RequestHook {
@@ -2811,6 +2822,7 @@ public:
   }
 
   ~Impl() noexcept(false) {
+    unwindDetector.catchExceptionsIfUnwinding([&]() {
       // std::unordered_map doesn't like it when elements' destructors throw, so carefully
       // disassemble it.
       if (!connections.empty()) {
@@ -2823,6 +2835,7 @@ public:
           deleteMe.add(kj::mv(entry.second));
         }
       }
+    });
   }
 
   Capability::Client restore(_::StructReader hostId, ObjectPointer::Reader objectId) {
@@ -2850,6 +2863,8 @@ private:
       ConnectionMap;
   ConnectionMap connections;
 
+  kj::UnwindDetector unwindDetector;
+
   RpcConnectionState& getConnectionState(kj::Own<VatNetworkBase::Connection>&& connection) {
     auto iter = connections.find(connection);
     if (iter == connections.end()) {