fix(swingset-liveslots): Move promise rejection responsibility into t…

…he kernel Fixes #6694
Agoric · Mar 16, 2023 · dd29ff3 · dd29ff3
1 parent 5d84157
commit dd29ff3
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Showing 4 changed files with 21 additions and 76 deletions.
diff --git a/packages/SwingSet/src/kernel/kernelQueue.js b/packages/SwingSet/src/kernel/kernelQueue.js
@@ -45,9 +45,7 @@ export function makeKernelQueueHandler(tools) {
       const p = kernelKeeper.getResolveablePromise(kpid, vatID);
       const { subscribers } = p;
       for (const subscriber of subscribers) {
-        if (subscriber !== vatID) {
-          notify(subscriber, kpid);
-        }
+        notify(subscriber, kpid);
       }
       kernelKeeper.resolveKernelPromise(kpid, rejected, data);
       const tag = rejected ? 'rejected' : 'fulfilled';

diff --git a/packages/swingset-liveslots/src/liveslots.js b/packages/swingset-liveslots/src/liveslots.js
@@ -552,7 +552,7 @@ function build(
   const knownResolutions = new WeakMap();
 
   /**
-   * Determines if a vref from an outbound argument
+   * Determines if a vref from a watched promise or outbound argument
    * identifies a promise that should be exported, and if so then
    * adds it to exportedVPIDs and sets up handlers.
    *
@@ -674,6 +674,7 @@ function build(
     // eslint-disable-next-line no-use-before-define
     convertValToSlot,
     convertSlotToVal: unmeteredConvertSlotToVal,
+    maybeExportPromise,
   });
 
   function convertValToSlot(val) {
@@ -1190,7 +1191,6 @@ function build(
     // upgrade, or if we acquire decider authority for a
     // previously-imported promise
     if (pRec) {
-      // TODO: insist that we do not have decider authority for promiseID
       meterControl.assertNotMetered();
       const val = m.unserialize(data);
       if (rejected) {
@@ -1431,10 +1431,7 @@ function build(
       Fail`buildRootObject() for vat ${forVatID} returned ${rootObject} with no interface`;
     // Need to load watched promises *after* buildRootObject() so that handler kindIDs
     // have a chance to be reassociated with their handlers.
-    watchedPromiseManager.loadWatchedPromiseTable(
-      unmeteredUnserialize,
-      unmeteredRevivePromise,
-    );
+    watchedPromiseManager.loadWatchedPromiseTable(unmeteredRevivePromise);
 
     const rootSlot = makeVatSlot('object', true, BigInt(0));
     valToSlot.set(rootObject, rootSlot);
@@ -1526,26 +1523,11 @@ function build(
     assert(!didStopVat);
     didStopVat = true;
 
-    // all vpids are either "imported" (kernel knows about it and
-    // kernel decides), "exported" (kernel knows about it but we
-    // decide), or neither (local, we decide, kernel is unaware). TODO
-    // this could be cheaper if we tracked all three states (make a
-    // Set for "neither") instead of doing enumeration and set math.
-
     try {
-      // mark "imported" plus "neither" for rejection at next startup
-      const importedVPIDsSet = new Set(importedVPIDs.keys());
-      watchedPromiseManager.prepareShutdownRejections(
-        importedVPIDsSet,
-        disconnectObjectCapData,
-      );
-      // reject all "exported" vpids now
-      const deciderVPIDs = Array.from(exportedVPIDs.keys()).sort();
       // eslint-disable-next-line @jessie.js/no-nested-await
       await releaseOldState({
         m,
         disconnectObjectCapData,
-        deciderVPIDs,
         syscall,
         exportedRemotables,
         addToPossiblyDeadSet,

diff --git a/packages/swingset-liveslots/src/watchedPromises.js b/packages/swingset-liveslots/src/watchedPromises.js
@@ -14,6 +14,7 @@ import { parseVatSlot } from './parseVatSlots.js';
  * @param {*} options.collectionManager
  * @param {import('@endo/marshal').ConvertValToSlot<any>} options.convertValToSlot
  * @param {import('@endo/marshal').ConvertSlotToVal<any>} options.convertSlotToVal
+ * @param {(vref: any) => boolean} options.maybeExportPromise
  */
 export function makeWatchedPromiseManager({
   syscall,
@@ -22,6 +23,7 @@ export function makeWatchedPromiseManager({
   collectionManager,
   convertValToSlot,
   convertSlotToVal,
+  maybeExportPromise,
 }) {
   const { makeScalarBigMapStore } = collectionManager;
   const { defineDurableKind } = vom;
@@ -103,41 +105,14 @@ export function makeWatchedPromiseManager({
   /**
    * Revives watched promises.
    *
-   * @param {import('@endo/marshal').Unserialize<unknown>} unserialize
    * @param {(vref: any) => Promise<any>} revivePromise
    * @returns {void}
    */
-  function loadWatchedPromiseTable(unserialize, revivePromise) {
-    const deadPromisesRaw = syscall.vatstoreGet('deadPromises');
-    if (!deadPromisesRaw) {
-      return;
-    }
-    const disconnectObjectCapData = JSON.parse(
-      syscall.vatstoreGet('deadPromiseDO'),
-    );
-    const disconnectObject = unserialize(disconnectObjectCapData);
-    syscall.vatstoreDelete('deadPromises');
-    syscall.vatstoreDelete('deadPromiseDO');
-    const deadPromises = new Set(deadPromisesRaw.split(','));
-
-    for (const [vpid, watches] of watchedPromiseTable.entries()) {
-      if (deadPromises.has(vpid)) {
-        watchedPromiseTable.delete(vpid);
-        for (const watch of watches) {
-          const [watcher, ...args] = watch;
-          void Promise.resolve().then(() => {
-            if (watcher.onRejected) {
-              watcher.onRejected(disconnectObject, ...args);
-            } else {
-              throw disconnectObject;
-            }
-          });
-        }
-      } else {
-        const p = revivePromise(vpid);
-        promiseRegistrations.init(vpid, p);
-        pseudoThen(p, vpid);
-      }
+  function loadWatchedPromiseTable(revivePromise) {
+    for (const vpid of watchedPromiseTable.keys()) {
+      const p = revivePromise(vpid);
+      promiseRegistrations.init(vpid, p);
+      pseudoThen(p, vpid);
     }
   }
 
@@ -178,7 +153,6 @@ export function makeWatchedPromiseManager({
 
     // TODO: add vpid->p virtual table mapping, to keep registration alive
     // TODO: remove mapping upon resolution
-    // TODO: track watched but non-exported promises, add during prepareShutdownRejections
     //  maybe check importedVPIDs here and add to table if !has
     void Promise.resolve().then(() => {
       const watcherVref = convertValToSlot(watcher);
@@ -205,35 +179,22 @@ export function makeWatchedPromiseManager({
         watchedPromiseTable.set(vpid, harden([...watches, [watcher, ...args]]));
       } else {
         watchedPromiseTable.init(vpid, harden([[watcher, ...args]]));
+
+        // Ensure that this vat's promises are rejected at termination.
+        if (maybeExportPromise(vpid)) {
+          syscall.subscribe(vpid);
+        }
+
         promiseRegistrations.init(vpid, p);
         pseudoThen(p, vpid);
       }
     });
   }
 
-  function prepareShutdownRejections(
-    importedVPIDsSet,
-    disconnectObjectCapData,
-  ) {
-    const deadPromises = [];
-    for (const vpid of watchedPromiseTable.keys()) {
-      if (!importedVPIDsSet.has(vpid)) {
-        deadPromises.push(vpid); // "exported" plus "neither" vpids
-      }
-    }
-    deadPromises.sort(); // just in case
-    syscall.vatstoreSet('deadPromises', deadPromises.join(','));
-    syscall.vatstoreSet(
-      'deadPromiseDO',
-      JSON.stringify(disconnectObjectCapData),
-    );
-  }
-
   return harden({
     preparePromiseWatcherTables,
     loadWatchedPromiseTable,
     providePromiseWatcher,
     watchPromise,
-    prepareShutdownRejections,
   });
 }
diff --git a/packages/swingset-liveslots/tools/fakeVirtualSupport.js b/packages/swingset-liveslots/tools/fakeVirtualSupport.js
@@ -230,6 +230,8 @@ export function makeFakeLiveSlotsStuff(options = {}) {
 
   function assertAcceptableSyscallCapdataSize(_capdatas) {}
 
+  const maybeExportPromise = _vref => false;
+
   return {
     syscall,
     allocateExportID,
@@ -250,6 +252,7 @@ export function makeFakeLiveSlotsStuff(options = {}) {
     dumpStore,
     setVrm,
     assertAcceptableSyscallCapdataSize,
+    maybeExportPromise,
   };
 }
 
@@ -281,6 +284,7 @@ export function makeFakeWatchedPromiseManager(
     collectionManager,
     convertValToSlot: fakeStuff.convertValToSlot,
     convertSlotToVal: fakeStuff.convertSlotToVal,
+    maybeExportPromise: fakeStuff.maybeExportPromise,
   });
 }
 /**