chore: timerRepeater.schedule() returns timestamp; add type & test (#…

…2246)

timerRepeater.schedule() returns timestamp. This adds that fact to the
type declaration and to the test. It's already being added to the documentation.

packages/SwingSet/src/vats/types.js

@@ -40,7 +40,7 @@
 
 /**
  * @typedef {Object} TimerRepeater
- * @property {(waker: TimerWaker) => void} schedule Returns the time scheduled for
+ * @property {(waker: TimerWaker) => Timestamp} schedule Returns the time scheduled for
  * the first call to `E(waker).wake()`.  The waker will continue to be scheduled
  * every interval until the repeater is disabled.
  * @property {() => void} disable Disable this repeater, so `schedule(w)` can't

packages/SwingSet/test/timer-device/bootstrap.js

@@ -24,7 +24,8 @@ export function buildRootObject(vatPowers, vatParameters) {
           },
         });
         const rptr = D(devices.timer).makeRepeater(argv[1], argv[2]);
-        D(devices.timer).schedule(rptr, handler);
+        const nextTime = D(devices.timer).schedule(rptr, handler);
+        log(`next scheduled time: ${nextTime}`);
       } else {
         throw new Error(`unknown argv mode '${argv[0]}'`);
       }

packages/SwingSet/test/timer-device/test-device.js

@@ -52,6 +52,7 @@ test('repeater', async t => {
   await c.step();
   t.deepEqual(c.dump().log, [
     'starting repeater test',
+    'next scheduled time: 3',
     'handler.wake(3) called 1 times.',
   ]);
 });
@@ -73,6 +74,7 @@ test('repeater2', async t => {
   await c.step();
   t.deepEqual(c.dump().log, [
     'starting repeater test',
+    'next scheduled time: 3',
     'handler.wake(3) called 1 times.',
     'handler.wake(7) called 2 times.',
   ]);
@@ -109,6 +111,7 @@ test('repeaterZero', async t => {
   await c.step();
   t.deepEqual(c.dump().log, [
     'starting repeater test',
+    'next scheduled time: 3',
     'handler.wake(3) called 1 times.',
     'handler.wake(6) called 2 times.',
     'handler.wake(9) called 3 times.',

packages/zoe/tools/manualTimer.js

@@ -23,14 +23,16 @@ export default function buildManualTimer(log, startValue = 0) {
   const makeRepeater = (delaySecs, interval, timer) => {
     /** @type {Array<TimerWaker> | null} */
     let wakers = [];
+    let nextWakeup;
 
     /** @type {TimerWaker} */
     const repeaterWaker = {
       async wake(timestamp) {
         if (!wakers) {
           return;
         }
-        timer.setWakeup(ticks + interval, repeaterWaker);
+        nextWakeup = ticks + interval;
+        timer.setWakeup(nextWakeup, repeaterWaker);
         await Promise.allSettled(wakers.map(waker => E(waker).wake(timestamp)));
       },
     };
@@ -42,14 +44,16 @@ export default function buildManualTimer(log, startValue = 0) {
           throw Error(`Cannot schedule on a disabled repeater`);
         }
         wakers.push(waker);
+        return nextWakeup;
       },
       disable() {
         wakers = null;
         timer.removeWakeup(repeaterWaker);
       },
     };
     harden(repeater);
-    timer.setWakeup(ticks + delaySecs, repeaterWaker);
+    nextWakeup = ticks + delaySecs;
+    timer.setWakeup(nextWakeup, repeaterWaker);
     return repeater;
   };