fix: allow local Presences to receive deliveries as well

Closes #1719

Author: michaelfig

packages/SwingSet/src/kernel/liveSlots.js

@@ -222,12 +222,6 @@ function build(
       if (isPromise(val)) {
         slot = exportPromise(val);
       } else {
-        const iface = getInterfaceOf(val);
-        // TODO unimplemented
-        assert(
-          iface === undefined,
-          details`cannot forward ${iface}; synthetic presences not implemented`,
-        );
         mustPassByPresence(val);
         slot = exportPassByPresence();
       }
@@ -380,19 +374,17 @@ function build(
     // the kernel. deliver() does not report such exceptions to the kernel.
 
     try {
-      if (!(method in t)) {
-        const names = Object.getOwnPropertyNames(t);
-        throw new TypeError(`target[${method}] does not exist, has ${names}`);
-      }
-      if (!(t[method] instanceof Function)) {
-        const ftype = typeof t[method];
-        const names = Object.getOwnPropertyNames(t);
-        throw new TypeError(
-          `target[${method}] is not a function, typeof is ${ftype}, has ${names}`,
-        );
+      // We have a presence, so forward to it.
+      let res;
+      if (args) {
+        // It has arguments, must be a method application.
+        res = HandledPromise.applyMethod(t, method, args);
+      } else {
+        // TODO: untested, but in principle sound.
+        // Just a getter.
+        res = HandledPromise.get(t, method);
       }
-      const res = t[method](...args);
-      Promise.resolve(res).then(notifySuccess, notifyFailure);
+      res.then(notifySuccess, notifyFailure);
     } catch (err) {
       notifyFailure(err);
     }

packages/eventual-send/src/index.js

@@ -355,15 +355,26 @@ export function makeHandledPromise() {
   // eslint-disable-next-line prefer-const
   forwardingHandler = {
     get: makeForwarder('get', (o, key) => o[key]),
-    applyMethod: makeForwarder('applyMethod', (o, optKey, args) => {
-      if (optKey === undefined || optKey === null) {
-        return o(...args);
+    applyMethod: makeForwarder('applyMethod', (t, method, args) => {
+      if (method === undefined || method === null) {
+        if (!(t instanceof Function)) {
+          const ftype = typeof t;
+          throw new TypeError(`target is not a function, typeof is ${ftype}`);
+        }
+        return t(...args);
+      }
+      if (!(method in t)) {
+        const names = Object.getOwnPropertyNames(t).sort();
+        throw new TypeError(`target[${method}] does not exist, has ${names}`);
       }
-      // console.log(`sending`, optKey, o[optKey], o);
-      if (typeof o[optKey] !== 'function') {
-        throw TypeError(`o[${JSON.stringify(optKey)}] is not a function`);
+      if (!(t[method] instanceof Function)) {
+        const ftype = typeof t[method];
+        const names = Object.getOwnPropertyNames(t).sort();
+        throw new TypeError(
+          `target[${method}] is not a function, typeof is ${ftype}, has ${names}`,
+        );
       }
-      return o[optKey](...args);
+      return t[method](...args);
     }),
   };