I fully agree with @ooeygui’s suggestion to make the API transition gradual in order not to
split the developer base. Not out of charity for ROS1, but to give ROS2 a shot at survival;
OSRF can just going to stop the buildfarm for Melodic, then how will the ROS1 community survive? There would have to be a thrid alternative to an OSRF supported ROS1 and an OSRF supported ROS2.
I fully agree with @ooeygui’s suggestion to make the API transition gradual in order not to
split the developer base.
That was a necessary discussion to lead 3 years ago. Different people pushed for it at the time. See e.g. this discussion: https://groups.google.com/d/msg/ros-sig-ng-ros/coG7Wdkbb4E/cm5SYVe4AwAJ
And one reaction was this statement at ROSCOn 2015: ROSCon 2015 Hamburg: Day 1 - Dirk Thomas: State of ROS 2 - demos and the technology behind on Vimeo, starting minute 46, Brian Gerkey took the mike:
“I’ll just add that one of the things that […] we talked about is what we colloquially refer to as a library shim. So this is something that you can imagine in any language […]. It would present a ROS1 API, but under the hood it would call into the ROS2 libraries. […] There are going to be different migration paths for different use-cases. We’re not a gang of super-villains out to give you a really bad day. We want to make this as useful as possible and make it as easy as possible to migrate.”
Then at ROSCon 2016, we got this talk:
ROSCon 2016 Seoul Day 1: ROS 2 Update on Vimeo (Minute 29:46) with William basically saying they could not get design a shim that works beyond simple cases. Also talks about experiments to unify the buildsystem (minute 32).
I don’t think there has been any encouraging development since. Given the TSC committee notes (ROS 2 TSC Meeting Minutes: September 6th, 2018): “When will ROS1 be EOL’d? […] It would be good to have a tentative plan for migration. The longer people can use ROS1 the less motivated they will be to move to ROS2.”, it seems that instead of providing a smooth migration path, just scaring the ROS1 community into all trashing their existing work and investing in rewriting their systems for ROS2.0 is favoured by OSRF and the TSC. Basically make the community pay for OSRFs decision to create ROS2 fast and backwards-incompatible, and worry about migration later.
So not sure if Brian today would repeat his above joke “We’re not a gang of super-villains out to give you a really bad day.” in light of all the talk of making Melodic the last release.