Ironicially, the source code for Chapter 7 does not appear to use Dart 2.12.0 or higher, therefore it is not null safe by default, which could confuse folks.
So, if you hit this chapter, and are using the supplementayr materials, double-check your pubspec.yaml to make sure you have
sdk: '>=2.12.0 < 3.0.0'
Ironic, indeed! I can’t believe I missed that. I’ll put a high priority on updating the supplementary materials this week. It’s not just Chapter 7. It’s all the chapters. Thank you very much for leaving a comment about this!
Ah, I found the problem! The default branch on the GitHub repo is currently pointing to the
editions/1.0 branch. The null safety update uses the
editions/1.1 branch. The link to the 1.1 branch is here:
I also opened a GitHub issue to change the default branch to the current one.
I’m glad that it turned out to be an easy fix and that I hadn’t forgotten something so basic as updating the Dart SDK environment version.
It has been fixed now. The default branch now points to the null safety version. Thank you again for bringing this up!
Thanks for the quick responses and followup!