Re-work flake.nix by lucperkins · Pull Request #2 · DeterminateSystems/try-minnows

lucperkins · 2026-05-15T15:37:27Z

This overhauls the flake to be more like the standard DetSys model.

Summary by CodeRabbit

Chores
- Added developer environment config to enable Nix flake usage.
- Restructured flake outputs to produce per-system apps, packages, dev shells, and checks.
- Pinned and updated flake inputs and build tooling; exported per-system formatter.
- Consolidated CI into a matrix-driven job for multiple platforms.
- Bumped Rust package edition to 2024.
- Removed TOML formatter rules and a prior license allowlist.

coderabbitai · 2026-05-15T15:37:38Z

Note

Reviews paused

It looks like this branch is under active development. To avoid overwhelming you with review comments due to an influx of new commits, CodeRabbit has automatically paused this review. You can configure this behavior by changing the reviews.auto_review.auto_pause_after_reviewed_commits setting.

Use the following commands to manage reviews:

@coderabbitai resume to resume automatic reviews.
@coderabbitai review to trigger a single review.

Use the checkboxes below for quick actions:

▶️ Resume reviews
🔍 Trigger review

📝 Walkthrough

Walkthrough

Enables direnv flake usage, pins minnows-related inputs, replaces flake-utils eachDefaultSystem with explicit per-system pkgs and minnowsSystems generation, emits per-system apps/devShells/checks/packages, defines an overlay that builds the crate via crane using Cargo metadata, updates Cargo edition to 2024, and consolidates CI into a matrix.

Changes

Nix Flake Modernization

Layer / File(s)	Summary
Environment setup and input pinning `.envrc`, `flake.nix` (inputs block)	Adds `.envrc` (`use flake`) and updates `flake.nix` inputs by pinning minnows-related flakes and changing crane/nixpkgs references.
Custom outputs structure and minnowsSystems `flake.nix` (outputs core), `system.nix`	Replaces `flake-utils.lib.eachDefaultSystem` with custom `pkgsFor`/system enumeration, derives rust package metadata from `./Cargo.toml`, and programmatically generates `minnowsSystems` by importing `./system.nix`.
DevShells, apps, checks, and packages `flake.nix` (devShells/apps/checks/packages)	Generates per-system `devShells` using `pkgs.craneLib.devShell`, exposes `apps.<system>.hello-minnows`, reduces `checks` to clippy/fmt plus hello-minnows, and makes `packages.<system>.default` point to `hello-minnows`.
Overlay and crate build `flake.nix` (overlays.default)	Defines `overlays.default` that derives Cargo `pname`/`version`/`meta.mainProgram`, cleans Cargo source, computes `cargoArtifacts` via `craneLib.buildDepsOnly`, exports `craneLib`/`src`/`commonArgs`/`cargoArtifacts`, and builds `hello-minnows`.
CI matrix consolidation `.github/workflows/ci.yaml`	Consolidates platform jobs into a single matrix-driven `checks` job, updates `success` job dependency, and pins `actions/checkout` to a commit SHA.
Formatter and schemas export `flake.nix`	Adds per-system `formatter` using `pkgs.nixfmt` and continues to export `schemas` from `inputs.minnows`.
Cargo metadata update `Cargo.toml`	Updates crate `edition` from `2021` to `2024`.

Estimated code review effort

🎯 4 (Complex) | ⏱️ ~45 minutes

Poem

🐇 I hop into the flake, a tiny eager thing,
direnv opens doors and pins the minnows' ring.
Crane stacks the build, Cargo hums in tune,
edition bumped to 2024 — a bright new moon. 🌙

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'Re-work flake.nix' directly corresponds to the main change: a comprehensive refactoring of the flake.nix file. While not maximally descriptive of all changes, it accurately reflects the primary modification.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

🧪 Generate unit tests (beta)

Create PR with unit tests
Commit unit tests in branch rework-flake

_{Comment @coderabbitai help to get the list of available commands and usage tips.}

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 `@flake.nix`:
- Around line 61-63: The dev shell references a missing checks output via the
attribute self.checks.${system} in the block starting with default =
pkgs.craneLib.devShell { checks = self.checks.${system}; } — either restore a
top-level checks output that provides a per-system attribute set named by
${system} (so self.checks.${system} exists), or remove/replace the checks
assignment in the devShell call (e.g., omit checks or pass an empty/default
attrset) so the dev shell no longer depends on the nonexistent
self.checks.${system}; update the flake outputs accordingly and ensure any
dependent code that expected checks is updated to match the chosen approach.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

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

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 31255c37-40e2-4b03-953c-dd5f863f0717

📥 Commits

Reviewing files that changed from the base of the PR and between 2caf12b and c2a898b.

⛔ Files ignored due to path filters (1)

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

📒 Files selected for processing (2)

.envrc
flake.nix

colemickens

Looks mostly fine but I do agree with CodeRabbit, we lost the Rust package checks with this change. Not essential, but I'd kind of like to keep them?

lucperkins · 2026-05-15T17:28:52Z

Yeah, I suppose the Rust service will probably end up being more ambitious than this 😀 I'll add those.

lucperkins · 2026-05-15T17:47:05Z

@colemickens I ported over the clippy and format checks. The nextest and Taplo checks didn't seem so useful in this context.

coderabbitai

🧹 Nitpick comments (1)

flake.nix (1)

78-86: 💤 Low value

Consider adding default app for convenience.

packages.default is defined, but apps.default is not, meaning nix run won't work without specifying .#hello-minnows.

Suggested addition

       apps = forEachSupportedSystem (
         { pkgs, ... }:
         {
+          default = self.apps.${system}.hello-minnows;
           hello-minnows = {
             type = "app";
             program = lib.getExe pkgs.hello-minnows;
           };
         }
       );

🤖 Prompt for 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.

In `@flake.nix` around lines 78 - 86, Add a default app mapping so `nix run` works
without specifying .#hello-minnows: in the apps block produced by
forEachSupportedSystem, add an entry named "default" that points to the same
program as "hello-minnows" (use the same lib.getExe pkgs.hello-minnows reference
or an alias to it) so apps.default exists alongside apps.hello-minnows; ensure
you reuse the existing pkgs/hello-minnows symbol and keep forEachSupportedSystem
behavior consistent.

🤖 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.

Nitpick comments:
In `@flake.nix`:
- Around line 78-86: Add a default app mapping so `nix run` works without
specifying .#hello-minnows: in the apps block produced by
forEachSupportedSystem, add an entry named "default" that points to the same
program as "hello-minnows" (use the same lib.getExe pkgs.hello-minnows reference
or an alias to it) so apps.default exists alongside apps.hello-minnows; ensure
you reuse the existing pkgs/hello-minnows symbol and keep forEachSupportedSystem
behavior consistent.

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: d545fbe9-91a1-46f9-9501-6730dcbcd444

📥 Commits

Reviewing files that changed from the base of the PR and between c2a898b and 1afda24.

📒 Files selected for processing (4)

Cargo.toml
deny.toml
flake.nix
taplo.toml

💤 Files with no reviewable changes (2)

deny.toml
taplo.toml

✅ Files skipped from review due to trivial changes (1)

Cargo.toml

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 @.github/workflows/ci.yaml:
- Around line 21-25: CI workflow uses floating tags for third-party actions;
replace the two occurrences of DeterminateSystems/determinate-nix-action@main
and DeterminateSystems/flakehub-cache-action@main with their respective
40-character commit SHAs (immutably pin both actions) so the workflow references
exact commits instead of `@main`; update both action lines to use the full commit
SHAs and keep the existing with: persist-credentials setting unchanged.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

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

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 265eef91-f119-4a79-9797-0bb0d7770193

📥 Commits

Reviewing files that changed from the base of the PR and between b246cd7 and 6380fc9.

📒 Files selected for processing (2)

.github/workflows/ci.yaml
flake.nix

🚧 Files skipped from review as they are similar to previous changes (1)

flake.nix

Re-work flake.nix

c2a898b

coderabbitai Bot reviewed May 15, 2026

View reviewed changes

Comment thread flake.nix

colemickens requested changes May 15, 2026

View reviewed changes

Add checks

1afda24

lucperkins requested a review from colemickens May 15, 2026 17:47

coderabbitai Bot reviewed May 15, 2026

View reviewed changes

lucperkins added 3 commits May 15, 2026 10:52

Add Nix formatter

a8e1674

Add default app output

b246cd7

Re-work Actions workflow

6380fc9

coderabbitai Bot reviewed May 15, 2026

View reviewed changes

Comment thread .github/workflows/ci.yaml

Remove code comments

7e948f5

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Re-work flake.nix#2

Re-work flake.nix#2
lucperkins wants to merge 6 commits into
mainfrom
rework-flake

lucperkins commented May 15, 2026 •

edited by coderabbitai Bot

Loading

Uh oh!

coderabbitai Bot commented May 15, 2026 •

edited

Loading

Reviews paused

Walkthrough

Changes

Estimated code review effort

Poem

Uh oh!

coderabbitai Bot left a comment

Uh oh!

Uh oh!

colemickens left a comment

Uh oh!

lucperkins commented May 15, 2026

Uh oh!

lucperkins commented May 15, 2026

Uh oh!

coderabbitai Bot left a comment

Uh oh!

coderabbitai Bot left a comment

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants

Conversation

lucperkins commented May 15, 2026 • edited by coderabbitai Bot Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Summary by CodeRabbit

Uh oh!

coderabbitai Bot commented May 15, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Reviews paused

Walkthrough

Changes

Estimated code review effort

Poem

Uh oh!

coderabbitai Bot left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

colemickens left a comment

Choose a reason for hiding this comment

Uh oh!

lucperkins commented May 15, 2026

Uh oh!

lucperkins commented May 15, 2026

Uh oh!

coderabbitai Bot left a comment

Choose a reason for hiding this comment

Uh oh!

coderabbitai Bot left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants

lucperkins commented May 15, 2026 •

edited by coderabbitai Bot

Loading

coderabbitai Bot commented May 15, 2026 •

edited

Loading