5.0.4 has broken change

[legokichi]

// fileA.js
const Buffer = require("buffer/").Buffer;
module.exports.A = new Buffer(10);

// fileB.js
const Buffer = require("buffer/").Buffer;
module.exports.B = new Buffer(10);

// fileC.js
const {A} = require("./fileA");
const {B} = require("./fileB");
console.log(Buffer.concat([A, B]));

in 5.0.3

$ browserify fileC.js > fileD.js | node
<Buffer 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00>

in 5.0.4

$ browserify fileC.js > fileD.js | node
[stdin]:472
      throw new TypeError('"list" argument must be an Array of Buffers')
      ^

TypeError: "list" argument must be an Array of Buffers
    at Function.concat ([stdin]:472:13)
    at Object.<anonymous> ([stdin]:1917:20)
    at Object.6../fileA ([stdin]:1919:4)
    at s ([stdin]:1:254)
    at e ([stdin]:1:425)
    at [stdin]:1:443
    at ContextifyScript.Script.runInThisContext (vm.js:25:33)
    at Object.exports.runInThisContext (vm.js:77:17)
    at Object.<anonymous> ([stdin]-wrapper:6:22)
    at Module._compile (module.js:556:32)

[feross]

@legokichi What version of browserify are you using? I tested with browserify v14 and could not reproduce the issue. Closing until enough info to reproduce is provided.

[feross]

Nevermind -- reinstalling browserify (which pulls in the latest buffer) and I can repro this now.

[feross]

It turns out that it's not possible to use instanceof Buffer safely, like I thought.

It's not possible to use instanceof Buffer reliably in a browserify context because there could be multiple different copies of the 'buffer' package in use.

This previous method (checking buf._isBuffer) works even for Buffer instances that were created from another copy of the buffer package.

NOTE: It's possible to have two different "instances" of the 'buffer' package, even if the 'buffer' package appears only once in the bundled code. This can happen if you require 'buffer' in different ways, for example:

require('buffer') vs. require('buffer/') vs. using the implicit Buffer global.

You can confirm this by browserifying this code:

console.log(require('buffer').Buffer === require('buffer/').Buffer) // will be false

So, for this reason, instanceof won't work.

[feross]

Released as 5.0.5.

[legokichi]

thanks a lot 😄