Instanceof fail with symbolic link

[GMartigny]

Hi,
I use Lerna in a multi-repo which create symbolic links between local packages. When using esm with it, tests for constructor fails. Whether you run instance instanceof Constructor or instance.constructor === Constructor, both fails.

I don't reproduce the bug when imported file aren't symbolic links.

Here's a repro-repo to demonstrate.

[dnalborczyk]

thank you @GMartigny !

just in case, could you also provide the node version you are experiencing this with as well as your operating system?

following your steps with node v10.8.0 on macOS:

To reproduce run :

npx lerna bootstrap
node
require("esm")
import "./index.js"
It should log false two time in the console instead of true.

my output is:

> require("esm")
esm enabled
> import './index.js'
instanceof false
== false
undefined

[dnalborczyk]

just reading your repo code ...

It should log false two time in the console instead of true.

I guess you mean the opposite: should log true two times in the console instead of false?

[GMartigny]

I'm on Ubuntu 14.06 with node 10.6.0

Well, I meant that the script would return false when it should return true.

[dnalborczyk]

@jdalton this seems to be a regression.

@GMartigny in the interim you might be able to use esm v3.0.71, your reduced repo seems to work, unless you need other bugfixes from patch 72 and above.

[GMartigny]

Just for the record, esm@3.0.71 don't reproduce the bug as you've already said. However, I now have an exception while using nyc.

I'll wait for a fix then =)

[jdalton]

For testing we can avoid pulling in various projects and test the root issues.
In this case symlinks fall into a couple buckets we don't have covered by tests.

• hard links (of files and folders)
• symlinks of folders in paths to a file
  (e.g. /a/path/this-is-a-symlink/the-file-is-not-a-symlink.js)

Update:

v3.0.75 is released 🎉

[GMartigny]

Since I update to esm@3.0.75, another error pops up. This is not reproduce by my example repo tho.

When I run npx nyc ava (but not when I do npx ava) I get a bunch of TypeError: Cannot read property 'f' of undefined. Should I open another issue ?

[dnalborczyk]

Should I open another issue ?

might be better for tracking. although without a repro it might be quite difficult to pinpoint the problem.

couple things you could try prior: definitely try the very latest release version first, currently v3.0.79, as there's still quite a bit of things being ironed out with each release. If I hit an exception like you are experiencing, I also usually delete the cache files (in node_modules/.cache, or run npm ci, if you are using npm 6+, which wipes and re-installs node_modules altogether), and see if it goes away (which is not to say that it's not a bug).

[jdalton]

Moving needs tests label to #717 and moving forward with that issue while locking this issue.