empty dynamic import breaks later code

[tjenkinson]

• Rollup Version: 1.27.2
• Operating System (or Browser): MacOS
• Node Version: v11.13.0

How Do We Reproduce?

git clone https://github.com/tjenkinson/rollup-bug-empty-dymanic-import.git
cd rollup-bug-empty-dymanic-import
npm install
npm test

Expected Behavior

A non empty bundle is generated that contains the console.log

Actual Behavior

An empty bundle is created. The empty dynamic import seems to cause the issue. If you comment out the console.log in 'a.js', it works.

[lukastaegert]

I understand, but the warning is technically correct, though the wording is wrong. It should read "created an empty chunk". If you do not throw for warnings, you will see that the entry chunk with the console.log is created. It is the dynamic chunk that is empty, which causes the warning. I think this should definitely be improved, if only to change the warning message in these cases. I guess it would also be helpful to include the name of the empty chunk in the warning message to make clear which chunk we are referring to.

[lukastaegert]

As for the warning itself, I think it still makes sense. Empty chunks will only be created in two cases: The target of a dynamic import does not have side-effects, or an entry chunk does not have side-effects. Both are under the user's control and are probably unintended.

[tjenkinson]

Ah 🤦‍♂

Makes sense. Sorry for the noise.

It should read "created an empty chunk". If you do not throw for warnings, you will see that the entry chunk with the console.log is created. It is the dynamic chunk that is empty, which causes the warning. I think this should definitely be improved, if only to change the warning message in these cases. I guess it would also be helpful to include the name of the empty chunk in the warning message to make clear which chunk we are referring to.

I opened a PR: #3244