We are happy and relieved to announce the first beta release of opam 2.4.0. You can view the full list of changes in the release note.

This version is an beta, we invite users to test it to spot previously unnoticed bugs as we head towards the stable release, which hopefully shouldn't take too long.

Try it!

The upgrade instructions are unchanged:

1. Either from binaries: run

For Unix systems

bash -c "sh <(curl -fsSL https://opam.ocaml.org/install.sh) --version 2.4.0~beta1"

or from PowerShell for Windows systems

Invoke-Expression "& { $(Invoke-RestMethod https://opam.ocaml.org/install.ps1) } -Version 2.4.0~beta1"

or download manually from the Github "Releases" page to your PATH.

1. Or from source, manually: see the instructions in the README.

You should then run:

opam init --reinit -ni

Changes

• Fixed some bugs in opam install --deps-only (and other commands simulating package pins, such as --depext-only) more visible in 2.4:
  • When a package pkg is already installed and opam install ./pkg --deps is called, if there is a conflict between the installed pkg dependencies and the definition of the local pkg, the conflict was not seen and the already installed pkg was kept (#6529)
  • No longer fetch and write the sources when simulating packages that were already pinned (#6532)
  • opam was triggering the reinstall of the package based on the already pinned packages instead of the expected newly simulated pinned packages (#6501)
  • opam was using the opam description of the wrong package in some cases (#6535)
• Change the behaviour of --deps-only, where it no longer requires unicity of package version between the request and the installed packages. In other words, if you have pkg.1 installed, installing dependencies of pkg.2 no longer removes pkg.1. This also allows to install dependencies of conflicting packages when their dependencies are compliant. (#6520)

Regression fixes from 2.4.0~alpha1

• Fix a regression where the internal sources directory was removed unexpectedly on reinstall actions, making opam re-fetch the package (#6554)
• Fixed a couple of regressions in opam update:
  • An unexpected stack overflow exception was raised when updating repositories with large files when opam is compiled with OCaml < 5.1 (#6513)
  • Updating a repository where a line was added at the end of a file without final newline character was making the update fail (#6527)

Windows binary

• Improve the prebuilt Windows binaries by including Cygwin's setup-x86_64.exe in the binary itself as fallback, in case cygwin.com is inaccessible (#6538)

Build changes

• Bump the downloaded-if-missing dune to 3.19.0, cppo to 1.8.0, ocamlgraph to 2.2.0, uutf to 1.0.4 and patch to 3.0.0~beta1 (#6527)
• Allows ./configure --without-dune to build with OCaml 5.4 (#6527)
• Add a --with-cygwin-setup option to the configure script, only available on Windows and disabled by default, which includes the optionally given setup-x86_64.exe binary inside the opam binary. If the option is given without a filename, the file with be fetched from cygwin.com (#6498)

API changes are also denoted in the release note linked above. This release also includes a couple of improvement and extensions to our testsuite.

Please report any issues to the bug-tracker.

Happy hacking!