Old build environments

[Michael Käppler]

Hi all,
a few days ago I wanted to try how some functionality in LilyPond
worked, when it was added long
time ago. (about 15 years ago, around 2.7.x or 2.8.x)
Not very surprisingly I could not even get the code to compile with my
current build setup.

That made we wonder if it would be a good idea to store a build
environment that is proven to work
with the code base every, say, minor version bump.

This could be a container (Docker? QEMU?) or an ISO image that can be
run inside a VM.
If the container formats are changing as quickly as the build
environments, this does not
make sense, however. But surely there are concepts out there for
long-term archivation
(or better, long-term reproducibility) of software.

What do you think?

Michael