util: make inherits work with classes #3455

targos · 2015-10-20T19:44:55Z

targos · 2015-10-20T19:47:00Z

test/parallel/test-util.js

-assert.throws(function() { util.inherits(null, ctor); }, TypeError);
-assert.doesNotThrow(function() { util.inherits(ctor, ctor); }, TypeError);
+assert.throws(function() { util.inherits(null, superCtor); }, TypeError);
+assert.doesNotThrow(function() { util.inherits(ctor, superCtor); }, TypeError);


Reason for this change:

> function A(){} undefined > util.inherits(A, A) TypeError: Cyclic __proto__ value at Function.setPrototypeOf (native) at Object.exports.inherits (util.js:764:10) ...

It doesn't make sense to make a function inherit from itself, but I guess it's still a semver-major change?

targos · 2015-10-20T19:51:48Z

updated the commit message

bnoordhuis · 2015-10-20T20:05:48Z

LGTM but more eyeballs are warranted. This PR changes C.prototype = Object.create(P.prototype) to C.prototype.__proto__ = P.prototype and that probably has subtle implications. R=@domenic maybe?

Apropos the commit log:

It is not allowed with ES2015 classes because the prototype property is read only.

Maybe add "in strict mode". Sloppy mode still lets you assign.

jasnell · 2015-10-20T20:21:47Z

It looks good on initial look through but needs more tests.

targos · 2015-10-20T20:48:39Z

Maybe add "in strict mode". Sloppy mode still lets you assign.

It doesn't throw when you try to assign, but it is a no-op:

class A{}
A.prototype = null;
console.log(A.prototype);

> node --harmony-sloppy test.js
A {}

bnoordhuis · 2015-10-20T20:54:39Z

Oh, good point. Never mind then.

domenic · 2015-10-22T18:53:54Z

As long as this is marked semver-major, it seems like a good change. It does have some subtle implications but all in the right direction.

targos · 2015-10-26T09:05:27Z

Rebased on master and updated tests. PTAL
CI: https://ci.nodejs.org/job/node-test-commit/971/

thefourtheye · 2015-10-26T11:44:28Z

LGTM

targos · 2015-10-26T19:37:29Z

@bnoordhuis & @jasnell LGTY ?

jasnell · 2015-10-26T19:38:28Z

LGTM

The current implementation overwrites the prototype of the target constructor. It is not allowed with ES2015 classes because the prototype property is read only. Use Object.setPrototypeOf instead. Fixes: nodejs#3452 PR-URL: nodejs#3455 Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com> Reviewed-By: James M Snell <jasnell@gmail.com>

Notable changes: * buffer: (Breaking) Removed both 'raw' and 'raws' encoding types from Buffer, these have been deprecated for a long time (Sakthipriyan Vairamani) nodejs#2859. * console: (Breaking) Values reported by console.time() now have 3 decimals of accuracy added (Michaël Zasso) nodejs#3166. * fs: - fs.readFile*(), fs.writeFile*(), and fs.appendFile*() now also accept a file descriptor as their first argument (Johannes Wüller) nodejs#3163. - (Breaking) In fs.readFile(), if an encoding is specified and the internal toString() fails the error is no longer thrown but is passed to the callback (Evan Lucas) nodejs#3485. - (Breaking) In fs.read() (using the fs.read(fd, length, position, encoding, callback) form), if the internal toString() fails the error is no longer thrown but is passed to the callback (Evan Lucas) nodejs#3503. * http: - Fixed a bug where pipelined http requests would stall (Fedor Indutny) nodejs#3342. - (Breaking) When parsing HTTP, don't add duplicates of the following headers: Retry-After, ETag, Last-Modified, Server, Age, Expires. This is in addition to the following headers which already block duplicates: Content-Type, Content-Length, User-Agent, Referer, Host, Authorization, Proxy-Authorization, If-Modified-Since, If-Unmodified-Since, From, Location, Max-Forwards (James M Snell) nodejs#3090. - (Breaking) The callback argument to OutgoingMessage#setTimeout() must be a function or a TypeError is thrown (James M Snell) nodejs#3090. - (Breaking) HTTP methods and header names must now conform to the RFC 2616 "token" rule, a list of allowed characters that excludes control characters and a number of separator characters. Specifically, methods and header names must now match /^[a-zA-Z0-9_!#$%&'*+.^`|~-]+$/ or a TypeError will be thrown (James M Snell) nodejs#2526. * node: - (Breaking) Deprecated the _linklist module (Rich Trott) nodejs#3078. - (Breaking) Removed require.paths and require.registerExtension(), both had been previously set to throw Error when accessed (Sakthipriyan Vairamani) nodejs#2922. * npm: Upgraded to version 3.3.6 from 2.14.7, see https://github.com/npm/npm/releases/tag/v3.3.6 for more details. This is a major version bump for npm and it has seen a significant amount of change. Please see the original npm v3.0.0 release notes for a list of major changes (Rebecca Turner) nodejs#3310. * src: (Breaking) Bumped NODE_MODULE_VERSION to 47 from 46, this is necessary due to the V8 upgrade. Native add-ons will need to be recompiled (Rod Vagg) nodejs#3400. * timers: Attempt to reuse the timer handle for setTimeout().unref(). This fixes a long-standing known issue where unrefed timers would perviously hold beforeExit open (Fedor Indutny) nodejs#3407. * tls: - Added ALPN Support (Shigeki Ohtsu) nodejs#2564. - TLS options can now be passed in an object to createSecurePair() (Коренберг Марк) nodejs#2441. - (Breaking) The default minimum DH key size for tls.connect() is now 1024 bits and a warning is shown when DH key size is less than 2048 bits. This a security consideration to prevent "logjam" attacks. A new minDHSize TLS option can be used to override the default. (Shigeki Ohtsu) nodejs#1831. * util: - (Breaking) util.p() was deprecated for years, and has now been removed (Wyatt Preul) nodejs#3432. - (Breaking) util.inherits() can now work with ES6 classes. This is considered a breaking change because of potential subtle side-effects caused by a change from directly reassigning the prototype of the constructor using `ctor.prototype = Object.create(superCtor.prototype, { constructor: { ... } })` to using `Object.setPrototypeOf(ctor.prototype, superCtor.prototype)` (Michaël Zasso) nodejs#3455. * v8: (Breaking) Upgraded to 4.6.85.25 from 4.5.103.35 (Ali Ijaz Sheikh) nodejs#3351. - Implements the spread operator, see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_operator for further information. - Implements new.target, see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/new.target for further information. * zlib: Decompression now throws on truncated input (e.g. unexpected end of file) (Yuval Brik) nodejs#2595. PR-URL: nodejs#3466

Notable changes: * buffer: (Breaking) Removed both 'raw' and 'raws' encoding types from Buffer, these have been deprecated for a long time (Sakthipriyan Vairamani) #2859. * console: (Breaking) Values reported by console.time() now have 3 decimals of accuracy added (Michaël Zasso) #3166. * fs: - fs.readFile*(), fs.writeFile*(), and fs.appendFile*() now also accept a file descriptor as their first argument (Johannes Wüller) #3163. - (Breaking) In fs.readFile(), if an encoding is specified and the internal toString() fails the error is no longer thrown but is passed to the callback (Evan Lucas) #3485. - (Breaking) In fs.read() (using the fs.read(fd, length, position, encoding, callback) form), if the internal toString() fails the error is no longer thrown but is passed to the callback (Evan Lucas) #3503. * http: - Fixed a bug where pipelined http requests would stall (Fedor Indutny) #3342. - (Breaking) When parsing HTTP, don't add duplicates of the following headers: Retry-After, ETag, Last-Modified, Server, Age, Expires. This is in addition to the following headers which already block duplicates: Content-Type, Content-Length, User-Agent, Referer, Host, Authorization, Proxy-Authorization, If-Modified-Since, If-Unmodified-Since, From, Location, Max-Forwards (James M Snell) #3090. - (Breaking) The callback argument to OutgoingMessage#setTimeout() must be a function or a TypeError is thrown (James M Snell) #3090. - (Breaking) HTTP methods and header names must now conform to the RFC 2616 "token" rule, a list of allowed characters that excludes control characters and a number of separator characters. Specifically, methods and header names must now match /^[a-zA-Z0-9_!#$%&'*+.^`|~-]+$/ or a TypeError will be thrown (James M Snell) #2526. * node: - (Breaking) Deprecated the _linklist module (Rich Trott) #3078. - (Breaking) Removed require.paths and require.registerExtension(), both had been previously set to throw Error when accessed (Sakthipriyan Vairamani) #2922. * npm: Upgraded to version 3.3.6 from 2.14.7, see https://github.com/npm/npm/releases/tag/v3.3.6 for more details. This is a major version bump for npm and it has seen a significant amount of change. Please see the original npm v3.0.0 release notes for a list of major changes (Rebecca Turner) #3310. * src: (Breaking) Bumped NODE_MODULE_VERSION to 47 from 46, this is necessary due to the V8 upgrade. Native add-ons will need to be recompiled (Rod Vagg) #3400. * timers: Attempt to reuse the timer handle for setTimeout().unref(). This fixes a long-standing known issue where unrefed timers would perviously hold beforeExit open (Fedor Indutny) #3407. * tls: - Added ALPN Support (Shigeki Ohtsu) #2564. - TLS options can now be passed in an object to createSecurePair() (Коренберг Марк) #2441. - (Breaking) The default minimum DH key size for tls.connect() is now 1024 bits and a warning is shown when DH key size is less than 2048 bits. This a security consideration to prevent "logjam" attacks. A new minDHSize TLS option can be used to override the default. (Shigeki Ohtsu) #1831. * util: - (Breaking) util.p() was deprecated for years, and has now been removed (Wyatt Preul) #3432. - (Breaking) util.inherits() can now work with ES6 classes. This is considered a breaking change because of potential subtle side-effects caused by a change from directly reassigning the prototype of the constructor using `ctor.prototype = Object.create(superCtor.prototype, { constructor: { ... } })` to using `Object.setPrototypeOf(ctor.prototype, superCtor.prototype)` (Michaël Zasso) #3455. * v8: (Breaking) Upgraded to 4.6.85.25 from 4.5.103.35 (Ali Ijaz Sheikh) #3351. - Implements the spread operator, see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_operator for further information. - Implements new.target, see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/new.target for further information. * zlib: Decompression now throws on truncated input (e.g. unexpected end of file) (Yuval Brik) #2595. PR-URL: #3466

mgtitimoli · 2016-02-09T22:26:41Z

This PR didn't fulfill what it was trying to achieve: make inherits work with classes, since the only thing that was done here, is the replacement of Object.create by the use of Object.setPrototypeOf, so it is doing exactly the same as before.

Instead of having removed the Object.create call, another statement like the following one should have been added:

Object.setPrototypeOf(ctor, superCtor);

Since what I wrote above would enable the inherits between classes and not only instances.

Despite the fact that there is an extra if, and a bad use of the ternary operator, below is the Babel implementation:

And as you can see they are doing exactly what I wrote before in the line 19.

syrnick · 2016-05-04T13:28:44Z

test/parallel/test-util-inherits.js

+// ES6 classes can inherit from a constructor function
+class E {
+  constructor() {
+    D.call(this);


Would this be better written as E.super_.call(this) ? That decouples E's constructor from the inherits in ln67.

targos added the util Issues and PRs related to the built-in util module. label Oct 20, 2015

targos reviewed Oct 20, 2015
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targos mentioned this pull request Oct 20, 2015

util.inherits cannot be used with ES6 classes #3452

Closed

targos force-pushed the fix-inherits-class branch from 4ac47bb to 3a9fd11 Compare October 20, 2015 19:51

bnoordhuis added the semver-major PRs that contain breaking changes and should be released in the next major version. label Oct 20, 2015

targos mentioned this pull request Oct 24, 2015

test: improve tests for util.inherits #3507

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targos force-pushed the fix-inherits-class branch from 3a9fd11 to 8a3edae Compare October 26, 2015 09:01

targos force-pushed the fix-inherits-class branch from 8a3edae to 29da8cf Compare October 27, 2015 05:41

targos merged commit 29da8cf into nodejs:master Oct 27, 2015

targos deleted the fix-inherits-class branch October 27, 2015 05:42

rvagg mentioned this pull request Oct 29, 2015

Release proposal: v5.0.0 #3466

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bnoordhuis mentioned this pull request Apr 12, 2016

util.inherits does not establish prototype chain #4179

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syrnick reviewed May 4, 2016
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util: make inherits work with classes #3455

util: make inherits work with classes #3455

targos commented Oct 20, 2015

targos Oct 20, 2015

targos commented Oct 20, 2015

bnoordhuis commented Oct 20, 2015

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domenic commented Oct 22, 2015

targos commented Oct 26, 2015

thefourtheye commented Oct 26, 2015

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mgtitimoli commented Feb 9, 2016

syrnick May 4, 2016

util: make inherits work with classes #3455

util: make inherits work with classes #3455

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