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fs: warn if no callback is passed to async calls

This patch issues a deprecation warning, if an asynchronous function
is called without a callback function.

PR-URL: https://github.com/nodejs/node/pull/7897
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Yorkie Liu <yorkiefixer@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
v7.x
Sakthipriyan Vairamani 9 years ago
parent
commit
f8f283b8f3
No known key found for this signature in database GPG Key ID: 800C90E774692D78
  1. 7
      lib/fs.js
  2. 40
      test/parallel/test-fs-make-callback.js

7
lib/fs.js

@ -83,6 +83,13 @@ function throwOptionsError(options) {
}
function rethrow() {
// TODO(thefourtheye) Throw error instead of warning in major version > 7
process.emitWarning(
'Calling an asynchronous function without callback is deprecated.',
'DeprecationWarning',
rethrow
);
// Only enable in debug mode. A backtrace uses ~1000 bytes of heap space and
// is fairly slow to generate.
if (DEBUG) {

40
test/parallel/test-fs-make-callback.js

@ -1,7 +1,7 @@
'use strict';
require('../common');
var assert = require('assert');
var fs = require('fs');
const common = require('../common');
const assert = require('assert');
const fs = require('fs');
function test(cb) {
return function() {
@ -13,16 +13,26 @@ function test(cb) {
// Verify the case where a callback function is provided
assert.doesNotThrow(test(function() {}));
// Passing undefined calls rethrow() internally, which is fine
assert.doesNotThrow(test(undefined));
process.once('warning', common.mustCall((warning) => {
assert.strictEqual(
warning.message,
'Calling an asynchronous function without callback is deprecated.'
);
// Anything else should throw
assert.throws(test(null));
assert.throws(test(true));
assert.throws(test(false));
assert.throws(test(1));
assert.throws(test(0));
assert.throws(test('foo'));
assert.throws(test(/foo/));
assert.throws(test([]));
assert.throws(test({}));
invalidArgumentsTests();
}));
// Passing undefined/nothing calls rethrow() internally, which emits a warning
assert.doesNotThrow(test());
function invalidArgumentsTests() {
assert.throws(test(null));
assert.throws(test(true));
assert.throws(test(false));
assert.throws(test(1));
assert.throws(test(0));
assert.throws(test('foo'));
assert.throws(test(/foo/));
assert.throws(test([]));
assert.throws(test({}));
}

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