What's new in Cabal/cabal-install 2.0 — improved new-build, Backpack, foreign libraries and more!

Tags: haskell.

A couple of weeks ago we’ve quietly released versions 2.0 of both Cabal and cabal-install after approximately a year of development. The 2.0 release incorporates more than 1500 commits by 64 different contributors. This post serves as a formal release announcement and describes what’s new and improved in version 2.0.

There is a number of backwards-incompatible Cabal library API changes in this release that affect packages with Custom setup scripts. Therefore cabal-install will by default use a previous version of Cabal to build setup scripts that don’t explicitly declare compatibility with Cabal 2.0. The 2.0 migration guide gives advice for package authors on how to adapt Custom setup scripts to backwards-incompatible changes in this release.

Major new features

Minor improvements and bug fixes

See the full Cabal 2.0 and cabal-install 2.0 changelogs for the complete list of changes in the 2.0 release.


Thanks to everyone who contributed code and bug reports. Full list of people who contributed patches to Cabal/cabal-install 2.0 is available here.

Looking forward

We plan to make a new release of Cabal/cabal-install before the end of the year – that is, around December 2017. We want to decouple the Cabal release cycle from the GHC one; that’ll allow us to release a new version of Cabal/cabal-install approximately every six months in the future. Main features that are currently targeted at the 2.2 milestone are:

We would like to encourage people considering contributing to take a look at the bug tracker on GitHub, take part in discussions on tickets and pull requests, or submit their own. The bug tracker is reasonably well maintained and it should be relatively clear to new contributors what is in need of attention and which tasks are considered relatively easy. Additionally, the list of potential projects from the latest hackathon and the tickets marked “easy” and “newcomer” can be used as a source of ideas for what to work on.

For more in-depth discussion there is also the cabal-devel mailing list and the #hackage IRC channel on FreeNode.


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