Cannot set property length of [object Object]

[oroce]

Buffer 3.5.0 breaks in Chrome (45.0.2454.85 (Official Build) (64-bit))

What I'm getting is

Uncaught TypeError: Cannot set property length of [object Object] which has only a getter

It happens when buffer tries to set .prototype.length to undefined, here: https://github.com/feross/buffer/blob/master/index.js#L372

I discovered this while I was rolling out our app's new version. Later I'm gonna try to put together a small demo.

(I'm using browserify 11.11.0 which uses buffer@3.5.0)

[byronanderson]

+1, causing me to need to start using npm shrinkwrap to get buffer 3.4.3

[CrisFavero]

+1

[feross]

Can someone share code to reproduce this error? I can't trigger it and the whole test suite passes on every supported browser...

[dcousens]

Assuming this bug can be confirmed, what is the best course of action anyway?

[feross]

Depends on the cause. We can either try to fix it, or revert the instanceof improvement I shipped in v3.5.0.

[CrisFavero]

The code i had that was causing this to show up was while using webpack and was unfortunately several libraries deep where it was triggered so i don't have a simple test case I know the file that directly had threw the error while using a buffer was https://github.com/primus/primus/blob/master/transformer.js likely not very helpful but you might be able to see a use case that would break it which is more obvious to you having written the buffer library

[nolanlawson]

@marioatlp Can you provide a stacktrace so we know where transformer was calling Buffer?

[oroce]

haha it seems I could reproduce the issue. It's not buffer but babelify when it is used as global transform breaks buffer.

Showcase: (check the console)

• --transform: http://purposeindustries.github.io/buffer-bug79/index.html
• --global-transform: http://purposeindustries.github.io/buffer-bug79/index-global.html

Code: https://github.com/purposeindustries/buffer-bug79

ps: you can solve the global transform by simply ignoring buffer: browserify index.js --global-transform [ babelify --ignore buffer ] -o dist.js

[jlbruno]

Looks like we're getting the same issue.
Also using webpack and babel together.

[oroce]

@jlbruno in webpack: add node_modules to the exclude list

module: {
  loaders: [
    {
      test: /\.jsx?$/,
      exclude: /node_modules/,
      loader: 'babel'
    }
  ]
}

[CrisFavero]

@oroce That solution is only helpful if the issue is a .jsx file in node_modules my issue was in standard JS. an alternative work around until this is fixed is to add to package.json dependencies section
"buffer": "3.4.3",
and to add to your webpack config file:

plugins: [
        new webpack.ContextReplacementPlugin(/buffer/, require('buffer'))
    ]

[jlbruno]

Ok, thanks....looks like 3 solutions have worked. Shrinkwrap (locking buffer to 3.4.3 by editing node-libs-browser package.json), excluding node_modules, and adding buffer at a top level dependency locked to v 3.4.3.

Thanks all. Time to figure out which is the least of the evils.

[lostrouter]

found one other solution for webpack based on

ps: you can solve the global transform by simply ignoring buffer: browserify index.js --global-transform [ babelify --ignore buffer ] -o dist.js

loaders: [
    { test: /\.jsx$/, loader: 'babel?stage=0&ignore=buffer' }
]

[nelix]

@lostrouter I would recommend not running babel on third party code, as often the transforms can break code that is unaware of es6. Such as making modules option strict by default.

[Ryuno-Ki]

I cross-referenced this issue against browserify, too. They should at least be aware of this issue.

Since I use traceur instead of babel, my solution was traceur --script ajar.js --out out/ajar.es6.js && browserify out/ajar.es6.js --ignore buffer -o out/ajar.js, whereby ajar.js is the main entry point in that project.

[mikemaccana]

3.4.3 still has the broken code:

$ grep version node_modules/buffer/package.json
  "version": "3.4.3"
$ grep 'length = undefined' node_modules/buffer/index.js
Buffer.prototype.length = undefined

[JSteunou]

Same here using webpack with https://github.com/mistadikay/strict-loader

<exception>: TypeError: Cannot set property length of [object Object] which has only a getter at Object.eval (webpack:///../~/webpack/~/node-libs-browser/~/buffer/index.js?:376:25) at eval (webpack:///../~/webpack/~/node-libs-browser/~/buffer/index.js?:1548:30) at ...
BP: undefined
Buffer: Buffer(arg)
INVALID_BASE64_RE: undefined
MAX_ARGUMENTS_LENGTH: undefined
SlowBuffer: SlowBuffer(subject, encoding)
allocate: allocate(that, length)
asciiSlice: asciiSlice(buf, start, end)
asciiToBytes: asciiToBytes(str)
asciiWrite: asciiWrite(buf, string, offset, length)
base64: Object
base64Slice: base64Slice(buf, start, end)
base64ToBytes: base64ToBytes(str)
base64Write: base64Write(buf, string, offset, length)
base64clean: base64clean(str)
binarySlice: binarySlice(buf, start, end)
binaryWrite: binaryWrite(buf, string, offset, length)
blitBuffer: blitBuffer(src, dst, offset, length)
byteLength: byteLength(string, encoding)
checkIEEE754: checkIEEE754(buf, value, offset, ext, max, min)
checkInt: checkInt(buf, value, offset, ext, max, min)
checkOffset: checkOffset(offset, ext, length)
checked: checked(length)
decodeCodePointsArray: decodeCodePointsArray(codePoints)
fromArray: fromArray(that, array)
fromArrayBuffer: fromArrayBuffer(that, array)
fromArrayLike: fromArrayLike(that, array)
fromBuffer: fromBuffer(that, buffer)
fromJsonObject: fromJsonObject(that, object)
fromNumber: fromNumber(that, length)
fromObject: fromObject(that, object)
fromString: fromString(that, string, encoding)
fromTypedArray: fromTypedArray(that, array)
global: Window
hexSlice: hexSlice(buf, start, end)
hexWrite: hexWrite(buf, string, offset, length)
ieee754: Object
isArray: isArray()
kMaxLength: kMaxLength()
objectWriteUInt16: objectWriteUInt16(buf, value, offset, littleEndian)
objectWriteUInt32: objectWriteUInt32(buf, value, offset, littleEndian)
rootParent: Object
slowToString: slowToString(encoding, start, end)
stringtrim: stringtrim(str)
this: Object
toHex: toHex(n)
typedArraySupport: typedArraySupport()
ucs2Write: ucs2Write(buf, string, offset, length)
utf8Slice: utf8Slice(buf, start, end)
utf8ToBytes: utf8ToBytes(string, units)
utf8Write: utf8Write(buf, string, offset, length)
utf16leSlice: utf16leSlice(buf, start, end)
utf16leToBytes: utf16leToBytes(str, units)
writeDouble: writeDouble(buf, value, offset, littleEndian, noAssert)
writeFloat: writeFloat(buf, value, offset, littleEndian, noAssert)

[JSteunou]

Ok I ran the test suit inside the same browser I have the bug in, and it is all good. Maybe someone (webpack?) is doing a freeze on the object, or something else.

[JSteunou]

Find it, don't add / use strict mode on Buffer.js mistadikay/strict-loader#5 (comment)

[scottburch]

I did a horrible patch in webpack for this issue that others might be able to use:

---- strict-stripper.js ------
module.exports = source => source.replace(/['"]use strict['"]/, '');

---- in webpack.config.js (loaders section) ------
{test: /buffer/, loader: ${__dirname}/strict-stripper.js},

[nolanlawson]

So I take it the steps to fix this bug are:

1. Add "use strict" to the top of index.js
2. Re-run the tests
3. Fix stuff until it works

In general, it looks like this could be fixed by simply hoisting the function Buffer () { ... } declaration to the top of the file.

[nolanlawson]

I can confirm that I can reproduce this by just adding 'use strict' to the top of index.js and then running npm run test-browser-local. I'm not sure how to fix it.

[nolanlawson]

^ fixed!

[JSteunou]

nicely done, thank you!

[feross]

Nicely done! Fix released as 3.6.0. And just like that, we're down to 0 open issues and 0 open PRs! 👍