Semantic versioning for Nix

FlakeHub enables you to use a subset of Semantic Versioning (SemVer) with your Nix flakes. The diagram below provides a quick refresher on the structure of versions in SemVer:

• Major versions represent backwards-incompatible API changes.
• Minor versions represent additions of backwards-compatible functionality.
• Patch versions represent backwards-compatible bug fixes.

Here’s an example SemVer-compatible version:

A breaking API change would entail a bump to major version 22 while a bug fix would entail a patch version bump to 13.

For things like pre-releases you can add extra information to the patch.

Supported operators

FlakeHub’s subset of SemVer supports the = operator.

Exact version (=)

The = operator signals that you want to resolve to an exact version. Here’s an example:

nix flake show "https://flakehub.com/f/DeterminateSystems/fh/=0.1.15"

Here, =0.1.15 could only resolve to 0.1.15 and this operation would fail if that version didn’t exist.

Wildcard operator (*)

The wildcard (*) operator allows for any version in that position.

• The version range * always uses the highest published version.
• 1.* allows any version with the major version of 1.
• 1.2.* allows any version with the major and minor version 1.2.

nix flake show "https://flakehub.com/f/DeterminateSystems/flake-checker/*"

Here, * would resolve to the most recent version of the flake-checker flake.