Resolvo: Fast package resolver written in Rust

Resolvo implements a fast package resolution algorithm based on CDCL SAT solving.

Projects using resolvo

• rip: An async package resolver and installer for Python PyPI packages
• rattler: Conda package resolver and installer (non-async)
• resolvo-rpm: Experimental RPM resolver for Fedora / RedHat / OpenSUSE ... RPM packages
• ... add yours!

Features

If resolvo is unable to find a solution it outputs a human-readable error message:

The following packages are incompatible
├─ bluesky-widgets >=0, <100 can be installed with any of the following options:
│  └─ bluesky-widgets 42 would require
│     └─ suitcase-utils >=0, <54, which can be installed with any of the following options:
│        └─ suitcase-utils 53
└─ suitcase-utils >=54, <100 cannot be installed because there are no viable options:
   └─ suitcase-utils 54, which conflicts with the versions reported above.

Resolvo provides a generic interface which allows integrating the solver with a variety of package managers. For instance resolvo is used in rattler and pixi to solve packages from the conda ecosystem.

Originally resolvo started out as a port/fork of libsolv but it has since then diverged substantially. However, the same CDCL algorithm based on MiniSats An Extensible SAT-solver is still used underneath. Major differences compared to libsolv are:

• Resolvo does not come with built-in support for several packaging ecosystems but instead provides a generic interface to allow it to be used in different scenarios.
• Resolvo has support for incremental/lazy solving. This allows users to quickly find solutions in ecosystems where retrieving package metadata is expensive.
• Resolvo is considerably faster than libsolv in large complex cases.
• Resolvo can easily be used in multithreaded environments.
• Resolvo provides human-readable error messages out-of-the-box.
• Resolvo optionally provides an async interface to allow concurrent metadata fetching.
• However, Libsolv is more extensive and supports more complex queries.

C++ bindings

Resolvo ships C++ bindings (see cpp/). A runnable example that solves sudoku puzzles with the solver lives in cpp/examples. With Pixi you can build and run it from the repository root:

pixi run cpp-example-sudoku

Pass your own puzzle as an 81-character string (. or 0 for empty cells):

pixi run cpp-example-sudoku "53..7....6..195....98....6.8...6...34..8.3..17...2...6.6....28....419..5....8..79"

See the example README for more details.

Contributing 😍

We would love to have you contribute! See the CONTRIBUTION.md for more info. For questions, requests or a casual chat, we are very active on our discord server. You can join our discord server via this link.