Flake-based Nix distribution

[RhenCloud]

Closes #80

This pull request adds comprehensive Nix flake support to the project, enabling reproducible builds, development environments, and integration with both NixOS and Home Manager. The main changes include the introduction of a flake.nix file that defines the package, development shell, and modules, as well as updates to .envrc for automatic flake support.

Nix flake integration and packaging:

• Added a new flake.nix file that defines the lucy package build using Go, sets up a development shell with all necessary tools, and provides formatter configuration. The flake also exports NixOS and Home Manager modules for easy integration.
• Updated .envrc to automatically source nix-direnv and enable flake support, improving the developer experience when using direnv and Nix.

Summary by CodeRabbit

Summary

• New Features
  • Added Nix flake support to build Lucy per system, including embedded version/build details.
  • Added per-system development shells with Go tooling and a built-in Nix formatter.
  • Added NixOS and Home Manager modules to enable Lucy via configuration and install the chosen package.
  • Installation now includes Bash, Zsh, and Fish shell completions.
• Chores
  • Updated direnv setup to enable flake sourcing only when not already configured.
  • Extended ignore rules for direnv state and build artifacts.

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📝 Walkthrough

Walkthrough

Adds a Nix flake that packages Lucy, provides Go development tooling and formatting, exports NixOS and Home Manager modules, and enables local flake-based direnv workflows with generated artifacts ignored.

Changes

Nix integration

Layer / File(s)	Summary
Flake package and module outputs flake.nix	Builds Lucy with embedded Go metadata and shell completions, and exposes configurable NixOS and Home Manager modules.
Development shell and formatting flake.nix	Provides Go development tools, configures GOPATH and PATH, and exports nixfmt as the formatter.
Direnv activation and ignores .envrc, .gitignore	Loads pinned nix-direnv support, enables use flake, and ignores .direnv and result artifacts.

Estimated code review effort: 3 (Moderate) | ~20 minutes

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	The flake-based Nix support in flake.nix and .envrc fulfills the issue's request to use flakes while the project stabilizes.
Out of Scope Changes check	✅ Passed	The .gitignore addition is ancillary to the Nix setup, and no unrelated changes are present.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly summarizes the main change: adding a flake-based Nix setup for the project.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In @.envrc:
- Around line 1-3: Update the bootstrap condition in .envrc to compare the
loaded nix-direnv version against 3.0.6, rather than only checking whether
nix_direnv_version exists. Ensure an older preloaded direnvrc reloads the pinned
3.0.6 source while an equal or newer compatible version skips bootstrapping.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 97dd9c01-9b37-4ecb-8adb-524e76f241d7

📥 Commits

Reviewing files that changed from the base of the PR and between 2c98cb9 and a66d7ca.

⛔ Files ignored due to path filters (1)

• flake.lock is excluded by !**/*.lock

📒 Files selected for processing (3)

• .envrc
• .gitignore
• flake.nix

[RhenCloud]

Waiting for release, then the flake.nix will be rewritten with makeShellWrapper.

[github-code-quality]

Code Coverage Overview

Languages: Go

Go / code-coverage/go

The overall line coverage in commit 12dd017 in the main branch is 16%. Line coverage data for the main branch is not yet available.

Show a line coverage summary of the most covered files.

File	main	main 12dd017	+/-
upstream/provid...seforge_data.go	—	95%	—
upstream/provid...t_conversion.go	—	92%	—
state/compare.go	—	89%	—
workspace/works...e_ecosystems.go	—	87%	—
workspace/inter...t_executable.go	—	85%	—
state/service.go	—	77%	—
upstream/provid...r_conversion.go	—	73%	—
workspace/inter..._observation.go	—	67%	—
state/manifest.go	—	60%	—
state/lock.go	—	51%	—

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_{Updated September 10, 2026 04:33 UTC}