The current HEAD build breaks a lot of programs that work in 9.2.*
This is not acceptable; we can't just release stuff that breaks people's programs without giving any kind of warning.
At a minimum, to make a significant change, the old behavior should be maintained at least one release after being formally deprecated, with a public statement that the next release will cause the breakage. The intermediate release should support both the old and the new way, so that people can make the transition in a system that will run both. Then the next release can break the old way.
This must be spelled out in the release notes of the intermediate release, with instructions on how to make the transition. Otherwise our users will be here on this list asking for help, and we'll be explaining the same thing over and over. (And looking like incompetents who can't manage a release transition.)
Let's try not to break things so abruptly; it's bad for us and for our users.
* I've run into two particular breakages:
- reduce-left was removed; GJS and I have been using it. I'm putting it back in.
- fluid-let no longer works on runtime-defined bindings; again, GJS and I have a program that uses this, which works either in 9.2 or HEAD but not both. This one is much harder to fix and I'm not sure I can do it at all without reverting the relevant changes -- which I will do if that's the only way.