airframe-di: Next generation DI library

[xerial]

• Support only constructor injection!

  • If we use only constructor injection, no dependency to DI itself is necessary other than the design part
  • No need to worry about which injection to use (in-trait or constructor?). It will also reduce the learning cost. Half of the current documentation (https://wvlet.org/airframe/docs/airframe) will be unnecessary.

• Deprecate in-trait bindings

  • For supporting Scala 3 at ease. Writing macros for nested trait instantiation is the tricky part. If we use constructor injection, the code will be much simpler

• Migration plan

  • Retain the current airframe module as is.
  • Add a new module "airframe-di" so that the user can migrate to a new one at any timing.
  • The package name will be wvlet.airframe.di => Deprecate in-trait injection only from Scala 3! Use the same package name to reduce the confusion.

• Usage stats of in-trait bindings (inside TD)

  • bind[X] a lot!!!
  • bindLocal[X] only a few times
  • bindFactory[X] only a few times
  • So dropping bindLocal, bindFactory should be ok.

[xerial]

Airframe DI for Scala 3 (without in-trait bindings) is released as 21.5.1