add computrons to transcript results, when available

Any delivery that results in `metering.compute` (i.e. anything to an
xsnap worker) will record that number as `metering.computrons` in the
transcript delivery results.

Our standard replay code doesn't do anything with this:
`replayTranscript` ignores the old results. But it gives us something
to compare against during external/diagnostic replays.

packages/SwingSet/src/kernel/vat-warehouse.js

@@ -46,6 +46,12 @@ function recordSyscalls(origHandler) {
     // TODO add metering computrons to results
     /** @type {TranscriptDeliveryResults} */
     const tdr = { status: deliveryResult[0] };
+    if (deliveryResult[0] === 'ok') {
+      const usage = deliveryResult[2];
+      if (usage) {
+        tdr.metering = { computrons: usage.compute };
+      }
+    }
     const transcriptEntry = { d: vd, sc: syscalls, r: tdr };
     return transcriptEntry;
   };

packages/SwingSet/src/types-internal.js

@@ -112,7 +112,7 @@ export {};
  *          } TranscriptDelivery
  * @typedef { { s: VatSyscallObject, r: VatSyscallResult } } TranscriptSyscall
  * @typedef { { status: string, snapshotID: string } } TranscriptDeliverySaveSnapshotResults
- * @typedef { { status: string } } TranscriptDeliveryGenericResults
+ * @typedef { { status: string, metering?: { computrons: number } } } TranscriptDeliveryGenericResults
  * @typedef { TranscriptDeliverySaveSnapshotResults | TranscriptDeliveryGenericResults } TranscriptDeliveryResults
  * @typedef { { d: TranscriptDelivery, sc: TranscriptSyscall[], r: TranscriptDeliveryResults } } TranscriptEntry
  *

packages/SwingSet/test/transcript/test-transcript-entries.js

@@ -23,7 +23,10 @@ test('transcript of new vats', async t => {
     },
     vats: {
       static1: { bundleName: 'bundle' },
-      static2: { bundleName: 'bundle' },
+      static2: {
+        bundleName: 'bundle',
+        creationOptions: { managerType: 'local' },
+      },
     },
   };
   const kernelStorage = initSwingStore().kernelStorage;
@@ -70,6 +73,11 @@ test('transcript of new vats', async t => {
     ['initialize-worker', 'startVat'],
   );
 
+  // static2 is always managerType='local', so it should never have 'metering'
+  // in the transcript results
+  const teStartVat = t2[1];
+  t.falsy(teStartVat.r.metering);
+
   const kpid = c.queueToVatRoot('static1', 'create', [], 'panic');
   await c.run();
   t.is(c.kpStatus(kpid), 'fulfilled');
@@ -220,6 +228,12 @@ test('transcript spans', async t => {
   t.deepEqual(curSummary(), [].concat(load, boot, notify));
   t.deepEqual(fullSummary(), expectedFull);
 
+  // all delivery events should record computrons
+  const teStartVat = old(0)[1];
+  t.is(teStartVat.d[0], 'startVat');
+  t.truthy(teStartVat.r.metering);
+  t.is(typeof teStartVat.r.metering.computrons, 'number');
+
   // do some deliveries to trigger an XS heap snapshot event, creating
   // a new span
   const doSomeNothing = async () => {
@@ -236,6 +250,11 @@ test('transcript spans', async t => {
   t.deepEqual(curSummary(), [].concat(load, boot, notify, msgN(1)));
   t.deepEqual(fullSummary(), expectedFull);
 
+  const teNothing1 = cur().slice(-1)[0];
+  t.is(teNothing1.d[0], 'message');
+  t.truthy(teNothing1.r.metering);
+  t.is(typeof teNothing1.r.metering.computrons, 'number');
+
   c = await restart();
   t.deepEqual(curSummary(), [].concat(load, boot, notify, msgN(1)));