Isn't there a way to make BorderRadius.circular(arg) a const?

Isn't there a way to make BorderRadius.circular(arg) a const?

Nope, we have to create Radius object during construction.

https://github.com/flutter/flutter/blob/master/packages/flutter/lib/src/painting/border_radius.dart#L294

The reason we have the BorderRadius.circular(arg) constructor is to avoid requiring that people create the much more verbose alternative. But certainly for people (such as us!) who prefer the verbosity that allows const, it would be an interesting lint.

Thanks @grafovdenis!

Also might be a good prefer type lint, @a14n do you think that would be a good candidate?

Sure! People would be free to enable this lint if they like verbosity :). Feel free to file an issue on linter package!

@Piinks @Hixie @a14n
Thanks for the gratitude!
Me and dart-code-metrics team recently introduced such lint rule.
Feel free to use Dart Code Metrics as analyzer plugin instead of making a copy 😊

Sure! People would be free to enable this lint if they like verbosity :). Feel free to file an issue on linter package!

I'm generally curious, do you have a limitation on using community packages? Coz we provide an analyzer plugin with this rule already implemented, but you want to implement the same rule in the linter package instead.

For instance, if the motivation is not to depend on any community package (coz they can be abandoned, contain malicious code, etc.), then it's totally understandable.

It's more about minimizing the number of dependencies for the core packages. There's a number of complicated implications about using packages from the core framework, for example we have to pin everything which means that anybody using the framework has to use the exact version of the dependency that the framework uses (even if there's a newer version), there's the impact on the license file size (which is already ~1MB!), and so on. You are more than welcome to submit PRs to the linter package though. Many of the lints in the dart-code-metrics package look super-valuable.

(It's not just about who wrote the package, either, for example we currently depend on vector_math, which was made by the Dart team, but we're seriously considering inlining the relevant code into the Flutter framework to avoid having that dependency. We literally have a test that checks that nobody is adding more dependencies and flags them when they get added.)

Thank you for the answer! Honestly, I was not expecting that you pin every package version and have a test for dependencies, but now it explains a lot.

Yeah, we started doing that because otherwise any dependency that made a slight change that stopped the tool from compiling would mean that all our users would get stuck on a broken version and the tool would be unable to run to get them fixed. (And also any dependency that made an analyzer error pop up or anything like that on any of our tests anywhere would cause our CI to go red, which was happening at least once a week before we pinned everything.)

Isn't there a way to make BorderRadius.circular(arg) a const?

I can see that Radius.circular is now a const constructor then why can't BorderRadius.circular be a const constructor as well?

I think having BorderRadius.circular is very neat rather than going with BorderRadius.all to achieve the same thing.