Spurious issue running tests on travis.

[ljharb]

A significant percentage of the time I run builds on travis-ci, npm install fails when trying to install jscs - specifically esprima.

npm ERR! EEXIST, symlink '../esprima/bin/esparse.js'

See https://travis-ci.org/paulmillr/es6-shim/jobs/45910645 for an example.

Do you have any idea what's causing this? When this happens, I can occasionally just rerun the build and it passes, but sometimes the build never passes.

[markelog]

This is probably npm issue, like - npm/npm#6309

We don't do anything special for esprima here.

[ljharb]

Turns out this is absolutely a jscs issue - esprima and esprima-harmony-jscs both publish a binary named esparse, and as such, are incompatible as sibling dependencies.

Unless one of them renames their binary, jscs must not depend directly on both.

/@markelog

[markelog]

We discussed this issue in length in here - #787

Do you still see the error?

[markelog]

Yeah, given discussion in here. i'm reopening this.

/cc @Krinkle, @mikesherov

[ljharb]

Not as often as I used to, but yes, still occasionally.

[Krinkle]

Whether or not there is a bug in npm, the immediate cause is that node-jscs depends on esprima and esprima-harmony-jscs. They conflict because both packages export a esparse and esvalidate bin.

From what I can see, jscs doesn't use these bins (if it did, it would be uncertain which one it gets). Can we remove it from esprima-harmony-jscs? Or give the bin a different name?

[qfox]

@Krinkle 👍 for that.

Another solution is to have a proxy npm-package with esprima-harmony-jscs.

[markelog]

I don't see a reason why we still need a esprima-harmony-jscs it seems we can just update esprima to the latest 2.2 and let es6 be enabled by default.

@mikesherov ?

[qfox]

@markelog Yeah, I've tried Esprima 2.x with JSCS and it works well, but seems like we should inc major version.

[markelog]

Why?

[qfox]

@markelog Because we can't guarantee work of plugins.

[markelog]

Why?

[mikesherov]

Our form of esprima-harmony supports more of es6, namely generators, for of, and a few others. Once ESPrima has full es6 support, we'll ditch our fork.

[markelog]

@mikesherov okay, so it seems after 2.3 we can ditch it, although we can update esprima to 2.2?

[markelog]

@Krinkle, @ljharb could use current master in your CI-runs to see if problem is resolved?

[ljharb]

That's a bit tricky - is it something that couldn't be released in a patch version? (I'm waiting for one for another fix anyways)

[markelog]

Minor will be released very soon (hoping for monday) just wanted to be sure we all okay here, so we wouldn't need to release 1.13.1 or something.

It most certainly should be fixed, but i can't test it, can't reproduce it, so it's a shot in the dark.

[Krinkle]

@markelog It's hard to be sure since it is a race condition. Initial testing shows the problem is solved. I can't be sure until it is released because we have many different projects each with their own package.json that specifies the version.

[ljharb]

Just to close the loop; this hasn't happened for me in months, so the problem is solved for me. Thanks!