fix(nix): parse Nix versions without a patch component

[mikeland73]

Summary

Fixes #2766.

Newer Nix releases report versions that omit the patch component, for example:

nix (Nix) 2.33pre20251107_479b6b73

versionRegexp (used by parseInfo) required a major.minor.patch triple, so these versions failed to parse. Info.Version was then left empty, and the nix-version guard aborted every command with the confusing message:

Error: Devbox requires nix of version >= 2.12.0. Your version is . Please upgrade nix and try again.

This made Devbox unusable on machines running recent nixos-unstable / nightly Nix builds.

Fix

• versionRegexp: make the patch component optional ((?:\.(?P<patch>…))?) so two-component versions like 2.33pre20251107_479b6b73 parse, while 2.21.2 continues to parse as before.
• Info.AtLeast: extract the version-coercion logic into a new coerceSemver helper and add a missingPatchRegexp that inserts a zero patch (2.33pre… → 2.33.0-pre.20251107+479b6b73) before comparison. This keeps the existing prerelease handling (2.23.0pre20240526_7de033d6) working and makes patchless versions comparable with golang.org/x/mod/semver.

How was it tested?

• Added a 2.33pre20251107_479b6b73 case to TestParseVersionInfoShort (parses to name nix, version 2.33pre20251107_479b6b73).
• Added AtLeast assertions for the patchless prerelease version in TestVersionInfoAtLeast (>= 2.12.0, >= MinVersion, >= 2.33.0-pre.1, < 2.34.0).
• go test ./nix/ and go vet ./nix/ pass. All pre-existing version tests (including the Lix 2.90.0-beta.1 and prerelease cases) still pass.

cc @Electrenator (issue reporter)

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Generated by Claude Code

[Copilot]

Pull request overview

This pull request fixes Devbox’s Nix version detection and comparison for newer Nix builds that omit the patch component (e.g. 2.33pre20251107_479b6b73), preventing Info.Version from being left empty and avoiding erroneous “Your version is .” guard failures.

Changes:

• Updated versionRegexp to allow versions with only major.minor (optional patch) while preserving existing prerelease/build parsing.
• Refactored version comparison by adding coerceSemver, including logic to insert a .0 patch when missing before comparing with golang.org/x/mod/semver.
• Added unit tests covering parsing and AtLeast behavior for patchless prerelease versions.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
nix/nix.go	Makes Nix version parsing accept patchless versions and coerces them into valid semver for comparisons.
nix/nix_test.go	Adds regression tests for parsing and AtLeast comparisons with patchless prerelease versions.

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[mikeland73]

The one failing check (test (not-main, ubuntu-latest, project-tests-only, 2.18.0)) failed on an unrelated, environmental flake, not this change:

--- FAIL: TestExamples/development_elixir_elixir_hello_run_test.test
** (Mix) httpc request failed with: {:failed_connect, [{:to_address, {~c"builds.hex.pm", 443}},
   {:tls_alert, {:unsupported_certificate, ...

The elixir_hello example test couldn't complete a TLS handshake to builds.hex.pm (Hex's CDN) from the CI runner. This change only affects parsing of nix --version output, and this job runs nix 2.18.0 — a standard major.minor.patch version that parses identically with and without this patch — so the change is a no-op here. The relevant nix unit tests and the shellenv_node testscript passed.

A re-run of the failed job should clear it (I don't have permission to trigger one via the API).

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Generated by Claude Code