ESM modules breaking tests

[djMax]

At the least, I think this is a semver violation, but not sure the root cause. As of tap 12.4.0 our tests work fine, with 12.5, they all fail with this:

> tap --node-arg=-r --node-arg=@babel/register "tests/test_startup.js"

tests/test_startup.js ................................. 1/2 5s
  start app for test_startup
  not ok Unexpected token import
    stack: |
      SyntaxError: Unexpected token import
          Object._compile (node_modules/pirates/lib/index.js:99:24)
          Object.newLoader [as .js] (node_modules/pirates/lib/index.js:104:7)
      From previous event:
          GbService.configure (node_modules/@gasbuddy/service/src/Service.js:108:26)
          <anonymous>
    type: SyntaxError
    tapCaught: returnedPromiseRejection
    test: start app for test_startup

total ................................................. 1/2

I'm not sure the logic behind adding esm to tap, but it breaks babel in some way.

[isaacs]

@jdalton, is this related to the stuff that you were just working on to get it playing more nicely with NYC?

[jdalton]

How does tap order the --node-arg additions. Is esm loaded after or before?

[isaacs]

esm is loaded first, then whatever other node-arg arguments get appended to that.

[jdalton]

@isaacs Perfect! (esm has scenario tests with @babel/register)

@djMax Could you produce a small repro. That would help me diagnose the issue and get a fix out.

[isaacs]

In the meantime, update to tap v12.6, and add --no-esm if you prefer.

[jdalton]

@djMax I tried to simulate a repro and could not reproduce the issue on my end. If you manage to create a repro please feel free to post back here or at standard-things/esm/issues.

[djMax]

This module: https://github.com/gas-buddy/service if you install tap@12.5.0, will fail

[delvedor]

I had a similar problem as well, and this is my log:

.../node_modules/tap/lib/stack.js:1
TypeError: Cannot read property 'value' of undefined
    at Object.Module._extensions..js (module.js:586:10)

It happens only in Node v6. Updating to tap v12.6.0 and using --no-esm fixes the issue.

[jdalton]

@djMax Thanks, digging in.

Update:

Patched standard-things/esm@8b8bcd1

Update:

esm v3.2.12 is released 🎉

@delvedor If you have a small repro I'll dig into that too 💪

[delvedor]

@jdalton thanks! Unfortunately, I haven't. In my project I'm running tap in three different test suites and only one of them is failing. In none of them I'm using esm. So I have no idea what is causing this issue.

[jdalton]

What version of Node 6 are you using?

[delvedor]

v6.17.0

[jdalton]

Thanks @delvedor!

I narrowed down the issue to an engine bug in Node 6 I have to guard against. It seems in Node 6 a generator may not always return an object with .value or .done and may return undefined instead.

Update:

Related to this V8 bug https://bugs.chromium.org/p/v8/issues/detail?id=5322 with the --harmony flag.

Update:

Patch standard-things/esm@23a163a;

Update:

esm v3.2.14 is released 🎉