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'use strict';
const { Object } = primordials;
const {
safeToString
} = internalBinding('util');
const {
tickInfo,
promiseRejectEvents: {
kPromiseRejectWithNoHandler,
kPromiseHandlerAddedAfterReject,
kPromiseResolveAfterResolved,
kPromiseRejectAfterResolved
},
setPromiseRejectCallback,
triggerFatalException
} = internalBinding('task_queue');
// *Must* match Environment::TickInfo::Fields in src/env.h.
const kHasRejectionToWarn = 1;
const maybeUnhandledPromises = new WeakMap();
const pendingUnhandledRejections = [];
const asyncHandledRejections = [];
let lastPromiseId = 0;
const states = {
none: 0,
warn: 1,
strict: 2,
default: 3
};
let state;
function setHasRejectionToWarn(value) {
tickInfo[kHasRejectionToWarn] = value ? 1 : 0;
}
function hasRejectionToWarn() {
return tickInfo[kHasRejectionToWarn] === 1;
}
function promiseRejectHandler(type, promise, reason) {
if (state === undefined) {
const { getOptionValue } = require('internal/options');
state = states[getOptionValue('--unhandled-rejections') || 'default'];
}
switch (type) {
case kPromiseRejectWithNoHandler:
unhandledRejection(promise, reason);
break;
case kPromiseHandlerAddedAfterReject:
handledRejection(promise);
break;
case kPromiseResolveAfterResolved:
resolveError('resolve', promise, reason);
break;
case kPromiseRejectAfterResolved:
resolveError('reject', promise, reason);
break;
}
}
function resolveError(type, promise, reason) {
// We have to wrap this in a next tick. Otherwise the error could be caught by
// the executed promise.
process.nextTick(() => {
process.emit('multipleResolves', type, promise, reason);
});
}
function unhandledRejection(promise, reason) {
maybeUnhandledPromises.set(promise, {
reason,
uid: ++lastPromiseId,
warned: false
});
// This causes the promise to be referenced at least for one tick.
pendingUnhandledRejections.push(promise);
setHasRejectionToWarn(true);
}
function handledRejection(promise) {
const promiseInfo = maybeUnhandledPromises.get(promise);
if (promiseInfo !== undefined) {
maybeUnhandledPromises.delete(promise);
if (promiseInfo.warned) {
const { uid } = promiseInfo;
// Generate the warning object early to get a good stack trace.
// eslint-disable-next-line no-restricted-syntax
const warning = new Error('Promise rejection was handled ' +
`asynchronously (rejection id: ${uid})`);
warning.name = 'PromiseRejectionHandledWarning';
warning.id = uid;
asyncHandledRejections.push({ promise, warning });
setHasRejectionToWarn(true);
return;
}
}
setHasRejectionToWarn(false);
}
const unhandledRejectionErrName = 'UnhandledPromiseRejectionWarning';
function emitWarning(uid, reason) {
if (state === states.none) {
return;
}
const warning = getError(
unhandledRejectionErrName,
'Unhandled promise rejection. This error originated either by ' +
'throwing inside of an async function without a catch block, ' +
'or by rejecting a promise which was not handled with .catch(). ' +
`(rejection id: ${uid})`
);
try {
if (reason instanceof Error) {
warning.stack = reason.stack;
process.emitWarning(reason.stack, unhandledRejectionErrName);
} else {
process.emitWarning(safeToString(reason), unhandledRejectionErrName);
}
} catch {}
process.emitWarning(warning);
emitDeprecationWarning();
}
let deprecationWarned = false;
function emitDeprecationWarning() {
if (state === states.default && !deprecationWarned) {
deprecationWarned = true;
process.emitWarning(
'Unhandled promise rejections are deprecated. In the future, ' +
'promise rejections that are not handled will terminate the ' +
'Node.js process with a non-zero exit code.',
'DeprecationWarning', 'DEP0018');
}
}
// If this method returns true, at least one more tick need to be
// scheduled to process any potential pending rejections
function processPromiseRejections() {
while (asyncHandledRejections.length > 0) {
const { promise, warning } = asyncHandledRejections.shift();
if (!process.emit('rejectionHandled', promise)) {
process.emitWarning(warning);
}
}
let maybeScheduledTicks = false;
let len = pendingUnhandledRejections.length;
while (len--) {
const promise = pendingUnhandledRejections.shift();
const promiseInfo = maybeUnhandledPromises.get(promise);
if (promiseInfo === undefined) {
continue;
}
promiseInfo.warned = true;
const { reason, uid } = promiseInfo;
if (state === states.strict) {
fatalException(reason);
}
if (!process.emit('unhandledRejection', reason, promise) ||
// Always warn in case the user requested it.
state === states.warn) {
emitWarning(uid, reason);
}
maybeScheduledTicks = true;
}
return maybeScheduledTicks || pendingUnhandledRejections.length !== 0;
}
function getError(name, message) {
// Reset the stack to prevent any overhead.
const tmp = Error.stackTraceLimit;
Error.stackTraceLimit = 0;
// eslint-disable-next-line no-restricted-syntax
const err = new Error(message);
Error.stackTraceLimit = tmp;
Object.defineProperty(err, 'name', {
value: name,
enumerable: false,
writable: true,
configurable: true,
});
return err;
}
function fatalException(reason) {
let err;
if (reason instanceof Error) {
err = reason;
} else {
err = getError(
'UnhandledPromiseRejection',
'This error originated either by ' +
'throwing inside of an async function without a catch block, ' +
'or by rejecting a promise which was not handled with .catch().' +
` The promise rejected with the reason "${safeToString(reason)}".`
);
err.code = 'ERR_UNHANDLED_REJECTION';
}
triggerFatalException(err, true /* fromPromise */);
}
function listenForRejections() {
setPromiseRejectCallback(promiseRejectHandler);
}
module.exports = {
hasRejectionToWarn,
setHasRejectionToWarn,
listenForRejections,
processPromiseRejections
};
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