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nodejs/test/parallel/test-timers-immediate-queue-throw.js
Anatoli Papirovski 54062d30cf
timers: refactor setImmediate error handling
If an error is encountered during the processing of Immediates, schedule
the remaining queue to finish after all error handling code runs (if the
process is still alive to do so). The new changes make the Immediates
error handling behaviour entirely deterministic and predictable, as the
full queue will be flushed on each Immediates cycle, regardless of
whether an error is encountered or not.

Currently this processing is scheduled for nextTick which can yield
unpredictable results as the nextTick might happen as early as close
callbacks phase or as late as after the next event loop turns Immediates
all fully processed. The latter can result in two full cycles of
Immediates processing during one even loop turn.

The current implementation also doesn't differentiate between Immediates
scheduled for the current queue run or the next one, so Immediates that
were scheduled for the next turn of the event loop, will process
alongside the ones that were scheduled for the current turn.

PR-URL: https://github.com/nodejs/node/pull/17879
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>
2018-01-02 11:16:33 -05:00

54 lines
1.4 KiB
JavaScript

'use strict';
const common = require('../common');
const assert = require('assert');
const domain = require('domain');
// setImmediate should run clear its queued cbs once per event loop turn
// but immediates queued while processing the current queue should happen
// on the next turn of the event loop.
// In addition, if any setImmediate throws, the rest of the queue should
// be processed after all error handling is resolved, but that queue
// should not include any setImmediate calls scheduled after the
// processing of the queue started.
let threw = false;
let stage = -1;
const QUEUE = 10;
const errObj = {
type: Error,
message: 'setImmediate Err'
};
process.once('uncaughtException', common.expectsError(errObj));
process.once('uncaughtException', () => assert.strictEqual(stage, 0));
const d1 = domain.create();
d1.once('error', common.expectsError(errObj));
d1.once('error', () => assert.strictEqual(stage, 0));
const run = common.mustCall((callStage) => {
assert(callStage >= stage);
stage = callStage;
if (threw)
return;
setImmediate(run, 2);
}, QUEUE * 3);
for (let i = 0; i < QUEUE; i++)
setImmediate(run, 0);
setImmediate(() => {
threw = true;
process.nextTick(() => assert.strictEqual(stage, 1));
throw new Error('setImmediate Err');
});
d1.run(() => setImmediate(() => {
throw new Error('setImmediate Err');
}));
for (let i = 0; i < QUEUE; i++)
setImmediate(run, 1);