Rollup sometimes fails with “Cannot read properties of null (reading 'included')” when using “external”

[tkalliom]

Rollup Version

3.4.0

Operating System (or Browser)

Linux

Node Version (if applicable)

16.18.1

Link To Reproduction

https://github.com/tkalliom/rollup-isincluded-bug

Expected Behaviour

Rollup does not do anything with dependencies declared as external.

Actual Behaviour

Rollup does some processing with an external dependency, failing with Cannot read properties of null (reading 'included'). This is a regression; we encountered this trying to upgrade Rollup from 2.6 to 3.4.

There was some previous discussion regarding this issue in the comments of #4297 – others have run into this as well

[lukastaegert]

Thanks for the reproduction, it was very insightful. Fix at #4725 .

[rollup-bot]

This issue has been resolved via #4725 as part of rollup@3.5.0. You can test it via npm install rollup.