`throwUnlessParallelizable` and was unable to parallelize a plugin

[jmonster]

I think this is a silent but common problem across the ember ecosystem, but this particular repo is the one one currently blocking my project from building in parallel:

THROW_UNLESS_PARALLELIZABLE=1 yarn start
$ ember serve
[broccoli-persistent-filter:Babel > [Babel: ember-basic-dropdown]: Babel: ember-basic-dropdown] was configured to `throwUnlessParallelizable` and was unable to parallelize a plugin.
plugins:
1: name: unknown, location: unknown

[veelci]

I'm running into the same problem using both v2.0.15 and v3.0.21 of ember-basic-dropdown in separate projects.

[cibernox]

I'm not very familiar with what makes an addon parallelizable. What can be done on this addon to make it parallel?

[teakap]

@cibernox I'm experiencing the same issue. I think this is what you want to make it parallelizable:

https://github.com/babel/broccoli-babel-transpiler#parallel-transpilation

[teakap]

A bit more info about the warnings, on a fresh ember app.

After ember-power-select installation.

After ember-basic-dropdown installation.

[sly7-7]

@teakap I don't know if it's related, but I just encountered this error after upgrading ember-data to 4.6. I realized that an other addon was using ember-data on 3.28. having the two pointing to 4.6, nuking node_modules, and yarn.lock file, makes the build to work again.

@cibernox I also found https://github.com/typed-ember/ember-cli-typescript/pull/351/files where it seems to workaround the problem (but to be honest, I don't understand what that mean).

[mwhitworth]

From a brief investigation (console.log calls in broccoli-babel-transpiler), I think the ember-maybe-in-element dependency is the culprit - see https://github.com/DockYard/ember-maybe-in-element/issues/52 and the open PR https://github.com/DockYard/ember-maybe-in-element/pull/54 to address this issue

[mwhitworth]

I think this can be closed, since the issue lies in another project (which has already addressed the issue)