Dynamic imports wrongly loads static import dependencies inside packages

[SachaG]

When you use import() to dynamically import a file, you would expect that all of that file's static imports would also be loaded dynamically. In other words, if I load this file dynamically:

import SuperHeavyJSPackage from 'super-heavy-js-package';

Then SuperHeavyJSPackage will not be part of my app bundle.

While this works fine inside the imports directory, it seems like it doesn't inside the packages directory. What's more, apparently imports will run even when they shouldn't (for example, inside an if (false) {...} block).

Here's a reproduction I created with help from @Discordius, who found the issue:

https://github.com/SachaG/dynamic-imports-bug/tree/package

And here's the same code running out of imports to compare:

https://github.com/SachaG/dynamic-imports-bug/tree/imports

It seems like the problem has been around since 1.5 as far as I can tell.

[benjamn]

This is definitely a bug!

I don't expect this to mean much to anyone but me, but I've tracked the problem down to this line, which is executed when a Meteor package tries to import an npm package from the application node_modules directory. Specifically, the mistake seems to be that the forDynamicImport parameter is ignored, so we lose the crucial information that HeavyComponent.jsx was imported dynamically.

[Discordius]

Just as a quick question so I can decide whether to implement a hot fix myself: Do you have any guess how long it will be until I might be able to pull a fix to this? (ideally via npm and not via forking the repo)

[benjamn]

@Discordius You can try it now with Meteor 1.6: meteor update --release 1.6-rc.6. If you're not ready for that, we will probably back-port this to Meteor 1.5.3 (not yet released).