After a few more months brewing, we are pleased to announce a new beta release
of opam. With this new milestone, opam is reaching feature-freeze, with an
expected 2.0.0 by the beginning of next year.
This version brings many new features, stability fixes, and big improvements to
the local development workflows.
What's new
The features presented in past announcements:
local switches,
in-source package definition handling,
extended dependencies
are of course all present. But now, all the glue to make them interact nicely
together is here to provide new smooth workflows. For example, the following
command, if run from the source tree of a given project, creates a local switch
where it will restore a precise installation, including explicit versions of all
packages and pinnings:
opam switch create ./ --locked
this leverages the presence of opam.locked or <name>.opam.locked files,
which are valid package definitions that contain additional details of the build
environment, and can be generated with the
opam-lock plugin (the lock command may
be merged into opam once finalised).
But this new beta also provides a large amount of quality of life improvements,
and other features. A big one, for example, is the integration of a built-in
solver (derived from mccs and
glpk). This means that the opam binary
works out-of-the box, without requiring the external
aspcud solver, and on all
platforms. It is also faster.
Another big change is that detection of architecture and OS details is now done
in opam, and can be used to select the external dependencies with the new format
of the depexts:
field, but also to affect dependencies or build flags.
There is much more to it. Please see the
changelog, and the
updated manual.
How to try it out
Our warm thanks for trying the new beta and
reporting any issues you may hit.
-
The easiest is to use our pre-compiled binaries.
This script
will also make backups if you migrate from 1.x, and has an option to revert
back:
sh <(curl -sL https://raw.githubusercontent.com/ocaml/opam/master/shell/install.sh)
This uses the binaries from https://github.com/ocaml/opam/releases/tag/2.0.0-beta5
-
Another option is to compile from source, using an existing opam
installation. Simply run:
opam update; opam install opam-devel
and follow the instructions (you will need to copy the compiled binary to
your PATH).
-
Compiling by hand from the
inclusive source archive,
or from the git repo. Use
./configure && make lib-ext && make if you have OCaml >= 4.02.3 already
available; make cold otherwise.
If the build fails after updating a git repo from a previous version, try
git clean -fdx src/ to remove any stale artefacts.
Note that the repository format is different from that of opam 1.2. Opam 2 will
be automatically redirected from the
opam-repository to an automatically
rewritten 2.0 mirror, and is otherwise able to do the conversion on the fly
(both for package definitions when pinning, and for whole repositories). You may
not yet contribute packages in 2.0 format to opam-repository, though.
What we need tested
We are interested in all opinions and reports, but here are a few areas where
your feedback would be specially useful to us:
- Use 2.0 day-to-day, in particular check any packages you may be maintaining.
We would like to ensure there are no regressions due to the rewrite from 1.2
to 2.0.
- Check the quality of the solutions provided by the solver (or conflicts, when
applicable).
- Test the different pinning mechanisms (rsync, git, hg, darcs) with your
project version control systems. See the
--working-dir option.
- Experiment with local switches for your project (and/or
opam install DIR).
Give us feedback on the workflow. Use opam lock and share development
environments.
- If you have any custom repositories, please try the conversion to 2.0 format
with
opam admin upgrade --mirror on them, and use the generated mirror.
- Start porting your CI systems for larger projects to use opam 2, and give us
feedback on any improvements you need for automated scripting (e.g. the
--json output).