Js mixins, path mappings are applied even if modules are not used but are enabled

[speedupmate]

Js mixins and/or path mappings are applied even if modules are not used but are enabled. For example Magento 2 ships with Temando_Shipping extension , this defines mappings on few js files.

If Temando_Shipping is not configured from admin to be used on frontend , mappings still apply and affect the original behaviour that is needed when extension is not configured to be used.

Of course Temando_Shipping is just an example here , same applies to every mixin/mapping defined for any included extension in requirejs-config.js

Preconditions

1. All Magento 2 versions

Steps to reproduce

1. Install Magento with demo data 2.2.4 (don't configure Temando_Shipping)
2. Add stuff to cart , reach checkout
3. Temando_Shipping module mappings are active in checkout even if module is not enabled (not even arguing what issues it creates, but just to illustrate)

Expected result

1. If extension is not configured to be used, we expect that it does not affect whatever is target for a mixin cause there is no need for customisation
2. There needs to be a way to tie mixin enabling to configuration status not just enabled/disabled status of whole module. There might even be a need for more precise control on when mixins/mappings are applied by the area extension customises (by layout handler etc)

Actual result

1. Temando_Shipping module mappings are active in checkout even if shipping method is not enabled from configuration.
2. Dependant on developer skill or amount of methods altered this affects other extensions or even default modules to work as expected

[DanielRuf]

The JS files are also always loaded.

Hi @speedupmate thank you for your report.
We've acknowledged the issue and added to our backlog.

[DrewML]

Possibly fixed by #19751

[speedupmate]

No its not fixed by this as the issue is that module is enabled in sytem but not configured from backend to be on, enabled, configured to work. Example as Temando_Shipping is a shipping method and is only meant to be included in code when module is enabled and configured to be "on" from shipping methods.

To fix this Magento either needs 2 states of declaring a module enabled:

1. enabled in system as bin/magento module:enable Some_Module
2. enabled in system and enabled to work/configured from backend as a flag in config

or

Each mixin, js mapping needs to check if its module is enable before applying their changes