fix(SwingSet): let vatManager creator override syscall comparison

In normal operation, any syscall divergence during replay is a fatal "anachrophobia error". But when we're replaying a vat for local debugging purposes, we might want to be more tolerant, e.g. Errors being serialized differently when the worker is in a debug mode. This add a `managerOptions.compareSyscalls` which can override the way transcript replay works. We export `requireIdentical()` so callers can use it to build their custom `compareSyscalls()` function.
Agoric · May 18, 2021 · 94f3740 · 94f3740
1 parent e45f5ad
commit 94f3740
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Showing 8 changed files with 49 additions and 15 deletions.
diff --git a/packages/SwingSet/src/kernel/vatManager/factory.js b/packages/SwingSet/src/kernel/vatManager/factory.js
@@ -65,6 +65,7 @@ export function makeVatManagerFactory({
       'vatParameters',
       'vatConsole',
       'name',
+      'compareSyscalls',
     ]);
     const { setup, bundle, enableSetup = false } = managerOptions;
     assert(setup || bundle);

diff --git a/packages/SwingSet/src/kernel/vatManager/manager-helper.js b/packages/SwingSet/src/kernel/vatManager/manager-helper.js
@@ -111,10 +111,15 @@ function makeManagerKit(
   kernelKeeper,
   vatSyscallHandler,
   workerCanBlock,
+  compareSyscalls,
 ) {
   assert(kernelSlog);
   const vatKeeper = kernelKeeper.getVatKeeper(vatID);
-  const transcriptManager = makeTranscriptManager(vatKeeper, vatID);
+  const transcriptManager = makeTranscriptManager(
+    vatKeeper,
+    vatID,
+    compareSyscalls,
+  );
 
   /** @type { (delivery: VatDeliveryObject) => Promise<VatDeliveryResult> } */
   let deliverToWorker;

diff --git a/packages/SwingSet/src/kernel/vatManager/manager-local.js b/packages/SwingSet/src/kernel/vatManager/manager-local.js
@@ -27,14 +27,15 @@ export function makeLocalVatManagerFactory(tools) {
   };
   // testLog is also a vatPower, only for unit tests
 
-  function prepare(vatID, vatSyscallHandler, meterRecord) {
+  function prepare(vatID, vatSyscallHandler, meterRecord, compareSyscalls) {
     const mtools = harden({ stopGlobalMeter, meterRecord, refillAllMeters });
     const mk = makeManagerKit(
       vatID,
       kernelSlog,
       kernelKeeper,
       vatSyscallHandler,
       true,
+      compareSyscalls,
     );
 
     function finish(dispatch) {
@@ -60,8 +61,13 @@ export function makeLocalVatManagerFactory(tools) {
     assert(!managerOptions.metered, X`unsupported`);
     assert(setup instanceof Function, 'setup is not an in-realm function');
 
-    const { syscall, finish } = prepare(vatID, vatSyscallHandler, null);
-    const { vatParameters } = managerOptions;
+    const { vatParameters, compareSyscalls } = managerOptions;
+    const { syscall, finish } = prepare(
+      vatID,
+      vatSyscallHandler,
+      null,
+      compareSyscalls,
+    );
     const { testLog } = allVatPowers;
     const helpers = harden({}); // DEPRECATED, todo remove from setup()
     const state = null; // TODO remove from setup()
@@ -85,6 +91,7 @@ export function makeLocalVatManagerFactory(tools) {
       vatConsole,
       liveSlotsConsole,
       virtualObjectCacheSize,
+      compareSyscalls,
     } = managerOptions;
     assert(vatConsole, 'vats need managerOptions.vatConsole');
 
@@ -101,7 +108,12 @@ export function makeLocalVatManagerFactory(tools) {
       });
     }
 
-    const { syscall, finish } = prepare(vatID, vatSyscallHandler, meterRecord);
+    const { syscall, finish } = prepare(
+      vatID,
+      vatSyscallHandler,
+      meterRecord,
+      compareSyscalls,
+    );
 
     const vatPowers = harden({
       ...baseVP,

diff --git a/packages/SwingSet/src/kernel/vatManager/manager-nodeworker.js b/packages/SwingSet/src/kernel/vatManager/manager-nodeworker.js
@@ -40,6 +40,7 @@ export function makeNodeWorkerVatManagerFactory(tools) {
       vatParameters,
       virtualObjectCacheSize,
       enableDisavow,
+      compareSyscalls,
     } = managerOptions;
     assert(!managerOptions.metered, 'not supported yet');
     assert(!managerOptions.enableSetup, 'not supported at all');
@@ -53,6 +54,7 @@ export function makeNodeWorkerVatManagerFactory(tools) {
       kernelKeeper,
       vatSyscallHandler,
       false,
+      compareSyscalls,
     );
 
     // start the worker and establish a connection

diff --git a/packages/SwingSet/src/kernel/vatManager/manager-subprocess-node.js b/packages/SwingSet/src/kernel/vatManager/manager-subprocess-node.js
@@ -20,6 +20,7 @@ export function makeNodeSubprocessFactory(tools) {
       vatParameters,
       virtualObjectCacheSize,
       enableDisavow,
+      compareSyscalls,
     } = managerOptions;
     assert(!managerOptions.metered, 'not supported yet');
     assert(!managerOptions.enableSetup, 'not supported at all');
@@ -30,6 +31,7 @@ export function makeNodeSubprocessFactory(tools) {
       kernelKeeper,
       vatSyscallHandler,
       false,
+      compareSyscalls,
     );
 
     // start the worker and establish a connection

diff --git a/packages/SwingSet/src/kernel/vatManager/manager-subprocess-xsnap.js b/packages/SwingSet/src/kernel/vatManager/manager-subprocess-xsnap.js
@@ -54,6 +54,7 @@ export function makeXsSubprocessFactory({
       enableDisavow,
       name,
       metered,
+      compareSyscalls,
     } = managerOptions;
     assert(
       !managerOptions.enableSetup,
@@ -65,6 +66,7 @@ export function makeXsSubprocessFactory({
       kernelKeeper,
       vatSyscallHandler,
       true,
+      compareSyscalls,
     );
 
     /** @type { (item: Tagged) => unknown } */

diff --git a/packages/SwingSet/src/kernel/vatManager/transcript.js b/packages/SwingSet/src/kernel/vatManager/transcript.js
@@ -1,6 +1,20 @@
 import djson from '../djson';
 
-export function makeTranscriptManager(vatKeeper, vatID) {
+export function requireIdentical(vatID, originalSyscall, newSyscall) {
+  if (djson.stringify(originalSyscall) !== djson.stringify(newSyscall)) {
+    console.log(`anachrophobia strikes vat ${vatID}`);
+    console.log(`expected:`, djson.stringify(originalSyscall));
+    console.log(`got     :`, djson.stringify(newSyscall));
+    return new Error(`historical inaccuracy in replay of ${vatID}`);
+  }
+  return undefined;
+}
+
+export function makeTranscriptManager(
+  vatKeeper,
+  vatID,
+  compareSyscalls = requireIdentical,
+) {
   let weAreInReplay = false;
   let playbackSyscalls;
   let currentEntry;
@@ -44,16 +58,11 @@ export function makeTranscriptManager(vatKeeper, vatID) {
 
   let replayError;
 
-  function simulateSyscall(scObj) {
+  function simulateSyscall(newSyscall) {
     const s = playbackSyscalls.shift();
-
-    if (djson.stringify(s.d) !== djson.stringify(scObj)) {
-      console.log(`anachrophobia strikes vat ${vatID}`);
-      console.log(`expected:`, djson.stringify(s.d));
-      console.log(`got     :`, djson.stringify(scObj));
-      if (!replayError) {
-        replayError = new Error(`historical inaccuracy in replay of ${vatID}`);
-      }
+    const newReplayError = compareSyscalls(vatID, s.d, newSyscall);
+    if (newReplayError) {
+      replayError = newReplayError;
       throw replayError;
     }
     return s.response;

diff --git a/packages/SwingSet/src/types.js b/packages/SwingSet/src/types.js
@@ -27,6 +27,7 @@
  *   vatParameters: Record<string, unknown>,
  *   virtualObjectCacheSize: number,
  *   name: string,
+ *   compareSyscalls?: (originalSyscall: {}, newSyscall: {}) => Error | undefined,
  * } & (HasBundle | HasSetup)} ManagerOptions
  */