[Bug] Ember Canary breaks build

[pichfl]

🐞 Describe the Bug

I'm a maintainer of ember-promise-modals and all recent pipelines—even ones that do not include any code changes at all—are failing on recent Canary builds.

🔬 Minimal Reproduction

See any runs of our test suite: https://github.com/mainmatter/ember-promise-modals/actions/runs/3534915439/jobs/5932359590

Or:

• Install ember-source@4.10.0-alpha.1.canary+636e3
• Run tests locally with CI=true (note: they pass if CI=false! This nearly cost me my sanity)

😕 Actual Behavior

Unchanged tests do not complete.

See error log

not ok 1 Chrome 107.0 - [undefined ms] - Global error: Uncaught TypeError: (0 , _emberBabel.extends) is not a function at http://localhost:7357/assets/vendor.js, line 13677
[63](https://github.com/mainmatter/ember-promise-modals/actions/runs/3534915439/jobs/5932359590#step:6:64)
    ---
[64](https://github.com/mainmatter/ember-promise-modals/actions/runs/3534915439/jobs/5932359590#step:6:65)
        browser log: |
[65](https://github.com/mainmatter/ember-promise-modals/actions/runs/3534915439/jobs/5932359590#step:6:66)
            {"type":"error","text":"Uncaught TypeError: (0 , _emberBabel.extends) is not a function at http://localhost:7357/assets/vendor.js, line 13677\n","testContext":{}}
[66](https://github.com/mainmatter/ember-promise-modals/actions/runs/3534915439/jobs/5932359590#step:6:67)
    ...
[67](https://github.com/mainmatter/ember-promise-modals/actions/runs/3534915439/jobs/5932359590#step:6:68)
not ok 2 Chrome 107.0 - [undefined ms] - Global error: Uncaught TypeError: (0 , _emberBabel.extends) is not a function at http://localhost:7357/assets/vendor.js, line 13677
[68](https://github.com/mainmatter/ember-promise-modals/actions/runs/3534915439/jobs/5932359590#step:6:69)
    ---
[69](https://github.com/mainmatter/ember-promise-modals/actions/runs/3534915439/jobs/5932359590#step:6:70)
        browser log: |
[70](https://github.com/mainmatter/ember-promise-modals/actions/runs/3534915439/jobs/5932359590#step:6:71)
            {"type":"error","text":"Uncaught TypeError: (0 , _emberBabel.extends) is not a function at http://localhost:7357/assets/vendor.js, line 13677\n","testContext":{"state":"complete"}}
[71](https://github.com/mainmatter/ember-promise-modals/actions/runs/3534915439/jobs/5932359590#step:6:72)
    ...
[72](https://github.com/mainmatter/ember-promise-modals/actions/runs/3534915439/jobs/5932359590#step:6:73)
not ok 3 Chrome 107.0 - [undefined ms] - Global error: Uncaught Error: Could not find module `@ember/test-helpers` imported from `dummy/tests/test-helper` at http://localhost:7357/assets/vendor.js, line 266
[73](https://github.com/mainmatter/ember-promise-modals/actions/runs/3534915439/jobs/5932359590#step:6:74)
    ---
[74](https://github.com/mainmatter/ember-promise-modals/actions/runs/3534915439/jobs/5932359590#step:6:75)
        browser log: |
[75](https://github.com/mainmatter/ember-promise-modals/actions/runs/3534915439/jobs/5932359590#step:6:76)
            {"type":"error","text":"Uncaught Error: Could not find module `@ember/test-helpers` imported from `dummy/tests/test-helper` at http://localhost:7357/assets/vendor.js, line 266\n","testContext":{"state":"complete"}}
[76](https://github.com/mainmatter/ember-promise-modals/actions/runs/3534915439/jobs/5932359590#step:6:77)
    ...
[77](https://github.com/mainmatter/ember-promise-modals/actions/runs/3534915439/jobs/5932359590#step:6:78)
not ok 4 Chrome 107.0 - [undefined ms] - Global error: Uncaught Error: The tests file was not loaded. Make sure your tests index.html includes "assets/tests.js". at http://localhost:7357/346326029182/tests/index.html?hidepassed, line 46
[78](https://github.com/mainmatter/ember-promise-modals/actions/runs/3534915439/jobs/5932359590#step:6:79)
    ---
[79](https://github.com/mainmatter/ember-promise-modals/actions/runs/3534915439/jobs/5932359590#step:6:80)
        browser log: |
[80](https://github.com/mainmatter/ember-promise-modals/actions/runs/3534915439/jobs/5932359590#step:6:81)
            {"type":"error","text":"Uncaught Error: The tests file was not loaded. Make sure your tests index.html includes \"assets/tests.js\". at http://localhost:7357/346326029182/tests/index.html?hidepassed, line 46\n","testContext":{"state":"complete"}}
[81](https://github.com/mainmatter/ember-promise-modals/actions/runs/3534915439/jobs/5932359590#step:6:82)
    ...
[82](https://github.com/mainmatter/ember-promise-modals/actions/runs/3534915439/jobs/5932359590#step:6:83)
```

🤔 Expected Behavior

Canary shouldn't fail my tests.

🌍 Environment

• Ember: Canary
• Node.js/npm: LTS
• OS: -
• Browser: -

➕ Additional Context

@mansona was mad enough to track down the trigger for this problem to this commit: 4e62cd6 - I have no idea what to do here.

[chriskrycho]

Thanks for the report. @dfreeman saw something similar last week, but it resolved itself.

Bizarrely, that config change should have literally zero impact on the generated build, but obviously something is going wrong there. Possibly the issue is this line, which I did not intend to introduce (I was experiment separately). It's possible something in the interaction between Ember CLI's custom handling for the pre-built Ember.js versions we distribute (we avoid re-building it for you) expects ES2017. I'll poke at that tomorrow morning and see.

Sorry for the annoyance, and thanks for running builds against Canary so that we catch these things early!

[dfreeman]

Aha, thank you for the ping @chriskrycho! I still hadn't managed to get our CI compatibility happy again and had just been putting off that work and blaming it on caching issues 😅

[chriskrycho]

Resolved by #20283. Thanks again for running against canary, folks! 🚀