Production builds produce incorrect browser runtimes for fastboot assets

[thoov]

Steps to reproduce:

1. git clone git@github.com:thoov/fastboot-macro-issue.git
2. cd fastboot-macro-issue && yarn

Then running the following commands:

• CLASSIC=true ember s
• CLASSIC=true ember s -prod
• ember s

And visiting http://ocalhost:4200 in the browser you will correctly see "browser". However if you run:

• ember s -prod

you will see "fastboot" printed indicating that the fastboot service is being used and not the app's service.

[thoov]

Some background information:

When we encounter a fastboot asset (such as fastboot/service/foo.js) we create a "switcher template" for it. This uses a macroCondition to create a "switch" for fastboot and browser imports which works fine in dev mode. However, in production mode we eliminate the runtime aspect of macros (and eliminate the "false" branches) and thus this conditional removes the app service and only leaves the fastboot one.

[ef4]

However, in production mode we eliminate the runtime aspect of macros (and eliminate the "false" branches) and thus this conditional removes the app service and only leaves the fastboot one.

That is how it's supposed to work. But we're supposed to run the build twice, so that we have both a browser-optimized asset and a fastboot-optimized asset. This is what the Variant type is for.

[thoov]

@ef4 Is this double build supposed to be working or is it not implemented?

[ef4]

It's supposed to be working and tested. See fastboot-app-test.ts.

[ef4]

That runs both in-browser tests and fastboot tests for both development and production.

[ef4]

I think this was fixed by #974