[darcs-devel] darcs-3 compatibility [was: Again: conversion to darcs-3]

[Ben Franksen]

Talking about our new approach to conversion made me consider the
following question, which I'd like us to discuss separately:

Is it really necessary for darcs-3 to be able to handle repos in the old
formats transparently, other than read-only? Could we perhaps even limit
support to conversion-only? We could promise to maintain a darcs-2
branch for the years to come, with no new features but the occasional
bugfix and compiler/library compatibility release.

Pro: This would allow us to clean up a lot of the baggage that darcs has
accumulated over the years, making it (probably a lot) easier to add new
features.

Con: OS distributions are often conservative and limited by their
tooling. Such a "hard" fork could mean that darcs-3 is offered as a
distro package under a new name for the package and for the program,
such that users may have to refer to the new version as "darcs3" or some
such. Think python2 vs. python3. On systems based on the debian package
format this could perhaps be mitigated using the "alternatives"
mechanism, but this means more effort for package maintainers. I have
very limited experience with other OSs / package managers.