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'use strict';
/*
* This is a regression test for
* https://github.com/nodejs/node-v0.x-archive/issues/15447 and
* https://github.com/nodejs/node-v0.x-archive/issues/9333.
*
* When a timer is added in another timer's callback, its underlying timer
* handle was started with a timeout that was actually incorrect.
*
* The reason was that the value that represents the current time was not
* updated between the time the original callback was called and the time
* the added timer was processed by timers.listOnTimeout. That led the
* logic in timers.listOnTimeout to do an incorrect computation that made
* the added timer fire with a timeout of scheduledTimeout +
* timeSpentInCallback.
*
* This test makes sure that a timer added by another timer's callback
* fires with the expected timeout.
*
* It makes sure that it works when the timers list for a given timeout is
* empty (see testAddingTimerToEmptyTimersList) and when the timers list
* is not empty (see testAddingTimerToNonEmptyTimersList).
*/
const common = require('../common');
const assert = require('assert');
const TIMEOUT = 100;
let nbBlockingCallbackCalls;
let latestDelay;
let timeCallbackScheduled;
// These tests are timing dependent so they may fail even when the bug is
// not present (if the host is sufficiently busy that the timers are delayed
// significantly). However, they fail 100% of the time when the bug *is*
// present, so to increase reliability, allow for a small number of retries.
let retries = 2;
function initTest() {
nbBlockingCallbackCalls = 0;
latestDelay = 0;
timeCallbackScheduled = 0;
}
function blockingCallback(retry, callback) {
++nbBlockingCallbackCalls;
if (nbBlockingCallbackCalls > 1) {
latestDelay = Date.now() - timeCallbackScheduled;
// Even if timers can fire later than when they've been scheduled
// to fire, they shouldn't generally be more than 100% late in this case.
// But they are guaranteed to be at least 100ms late given the bug in
// https://github.com/nodejs/node-v0.x-archive/issues/15447 and
// https://github.com/nodejs/node-v0.x-archive/issues/9333.
if (latestDelay >= TIMEOUT * 2) {
if (retries > 0) {
retries--;
return retry(callback);
}
assert.fail(`timeout delayed by more than 100% (${latestDelay}ms)`);
}
if (callback)
return callback();
} else {
// Block by busy-looping to trigger the issue
common.busyLoop(TIMEOUT);
timeCallbackScheduled = Date.now();
setTimeout(blockingCallback.bind(null, retry, callback), TIMEOUT);
}
}
function testAddingTimerToEmptyTimersList(callback) {
initTest();
// Call setTimeout just once to make sure the timers list is
// empty when blockingCallback is called.
setTimeout(
blockingCallback.bind(null, testAddingTimerToEmptyTimersList, callback),
TIMEOUT
);
}
function testAddingTimerToNonEmptyTimersList() {
// If both timers fail and attempt a retry, only actually do anything for one
// of them.
let retryOK = true;
const retry = () => {
if (retryOK)
testAddingTimerToNonEmptyTimersList();
retryOK = false;
};
initTest();
// Call setTimeout twice with the same timeout to make
// sure the timers list is not empty when blockingCallback is called.
setTimeout(
blockingCallback.bind(null, retry),
TIMEOUT
);
setTimeout(
blockingCallback.bind(null, retry),
TIMEOUT
);
}
// Run the test for the empty timers list case, and then for the non-empty
// timers list one.
testAddingTimerToEmptyTimersList(
common.mustCall(testAddingTimerToNonEmptyTimersList)
);