升级项目 Flutter SDK，迁移到空安全 - 包中的编译时错误

Question

We have decided to upgrade the Flutter version from 1.22 to 2.0 (migrating to null-safety) in an existing project.
We checkout Flutter v2.0.0 and then run the following command:

dart pub upgrade --null-safety

Flutter nicely resolves all dependency conflicts and sets new versions for packages.
Without changing min environment SDK in pubspec.yaml (staying at ">2.10.0 <3.0.0") we fix all breaking changes in the code.

All errors in vs code disappear so we can compile the code. But, when we do compile we get errors from packages eg reorderables, fl_chart, flutter_svg etc. stating some classes are undefined. It seems like packages were compiled with a higher SDK version and they weren't set min SDK version to match the one that they were compiled with.

So the package states it can be compiled with Flutter 2.10.0 but in reality, it fails to compile because in this version of Flutter it is missing some necessary imports.

My question is, is this a problem of packages or a problem in my way of processing with migration?
Is it that packages are lacking properly set min SDK?

Answer 1

My conclusion is that most packages are lacking correctly set SDK version constraints. It seems authors usually compile packages for a certain version and do not check min SDK version required. When running dependency resolver it seems to solve dependencies but in compile time it fails.