Keep supporting Flutter 2

[martin-braun]

Flutter 2 is not even one year old, but ffi 2.0.1 depends on SDK 2.17.0, which is Flutter 3. Can this be polyfilled to support SDK 2.16.2 (Flutter 2.10.5) for some more time please?

[dcharkes]

We bumped to Dart 2.16 because we introduced uses of https://api.dart.dev/stable/2.18.6/dart-ffi/AbiSpecificInteger-class.html.

• ABI-specific integers #128

We subsequently decided to revert that.

• Revert "Common C integer types (#128)" #141

Which reverted the Dart version back to 2.12.

Then we bumped to 2.17 in

• Replace HeapFree with CoTaskMemAlloc  #144

Most likely due to the reference to https://api.dart.dev/stable/2.18.6/dart-ffi/NativeFinalizer-class.html in the docs, which was introduced in 2.17.

If it's only the docs reference we could possibly try to revert back to Dart 2.12 which is Flutter 2.0.0.

[dcharkes]

In general, we'd like to be able to use new features introduces in Dart in this package.

See for example:

• Use memset for zeroing out memory on Windows in Dart 2.19 dart-lang/native#913

When we address this issue, we would bump to Dart 2.19.

@martin-braun what's your use case for staying at Flutter 2?

[dcharkes]

@martin-braun could you try #171 with a dependency override as git dependency to see if it does what you need?

[martin-braun]

@dcharkes Thank you for taking action so quick. Unfortunately, I had to decide to bump my plugin to Flutter 3 due to other non-related issues. I wish there was another way. I was requesting the backport, so that another plugin could start to work again, as my plugin is not depending on ffi, directly.

So in conclusion, it's not an issue anymore. For the future I hope that the Flutter team and Flutter plugin maintainers could try to give longer support times on legacy versions. Maybe an lts channel could be considered that plugin maintainers need to follow up.