Resolve Credo issues and enforce it in CI

[taras-tyshko]

🎯 Objective

Improve code quality and enforce coding standards by making Credo checks mandatory in CI, while resolving all existing code quality issues.

🔧 Changes

Enforced Credo in CI

• Update --mute-exit-status from .github/workflows/ci.yml on --min-priority low (full comment here Resolve Credo issues and enforce it in CI #2258 (comment))
• Credo will now fail the build when code quality issues are detected
• All existing issues have been resolved

#2258 (comment)

🐛 Credo Issues Fixed

Software Design Issues (21 files)

• Nested modules aliasing: Added proper alias statements for nested modules like X509.Certificate.Extension, Phoenix.Channel.Server, NervesHub.Telemetry.Customizations
• Examples: lib/nerves_hub/certificate.ex, lib/nerves_hub_web/plugs/configure_uploads.ex, lib/nerves_hub/extensions/health.ex

Readability Issues (6 files)

• Alias ordering: Fixed alphabetical ordering of alias statements
• Explicit try blocks: Converted to implicit try blocks in lib/nerves_hub/firmwares/update_tool/fwup.ex
• Zero-arity functions: Added parentheses to functions like def spec() in lib/nerves_hub_web/api_spec.ex
• Large numbers: Formatted with underscores (e.g., 578088 → 578_088)
• String literals: Replaced multi-quote strings with sigils in tests

Refactoring Opportunities (3 files)

• Cyclomatic complexity: Refactored friendly_blocked_until/1 in lib/nerves_hub_web/components/device_update_status.ex using pattern matching
• Complex macros: Split updated_live_view/0 and hooked_component/1 into smaller, focused functions
• Enum optimizations: Replaced Enum.map |> Enum.join with Enum.map_join in tests

Configuration Updates

• Disabled checks: Made TODO comments and @moduledoc tags optional in .credo.exs
• Why: TODO comments are acceptable in our codebase for tracking technical debt, and @moduledoc requirements would be too disruptive for existing modules

✅ Results

• 0 Credo warnings across 385 source files
• Improved readability and maintainability of complex macros
• Ensured code quality enforcement for future PRs via CI

[joshk]

Hi @taras-tyshko

Thank you for your recent PRs.

I like where this is going.

I think it might be going a little far in some cases. Credo is a good guide, as long as it does impact code clarity. I think there are a bunch of alias changes we can skip, and maybe instead ignore the credo warnings of.

[joshk]

Moving these to disabled means we won't see any output for them.

I would like to see the output but not have them fail credo.

[taras-tyshko]

GitHub Actions workflow update:

# Before
- name: Run Credo
  run: mix credo

# After  
- name: Run Credo
  run: mix credo --min-priority low

Ignored Priority Checks - Excluded from CI

📝 Design.TagTODO

# TODO comments are acceptable in our codebase, but we want to see them locally
{Credo.Check.Design.TagTODO, [priority: :ignore]},

---

📚 Readability.ModuleDoc

Missing @moduledoc tags

# ModuleDoc is not required in our codebase, but we want to see them locally  
{Credo.Check.Readability.ModuleDoc, [priority: :ignore]},

Key Change: Using priority: :ignore ensures these checks don't block CI but remain visible for local development feedback.

[taras-tyshko]

@joshk I think the priority: :ignore can help as to resolve that issue together with mix credo --min-priority low

[taras-tyshko]

@joshk, first of all, thanks for the feedback. I tried to resolve all your comments at PR. I would say I'm ready for a second round of review.

[kybishop]

Just wanted to put Quokka out there as an option. It will automatically keep your codebase in line with your credo configuration so that you don't have to manually fix things 🎉

[taras-tyshko]

Just wanted to put Quokka out there as an option. It will automatically keep your codebase in line with your credo configuration so that you don't have to manually fix things 🎉

[taras-tyshko]

Just wanted to put Quokka out there as an option. It will automatically keep your codebase in line with your credo configuration so that you don't have to manually fix things 🎉

@kybishop Sounds interesting. I didn't use it before. How about creating a new task and implement it later?

[joshk]

Thanks for your work on this, and sorry for the delay in reviewing the PR.

[taras-tyshko]

Update:
1. Big thanks to @joshk for the review.
2. We’ve split the macros changes into a separate PR: #2298
3. In general, we’re waiting for the Macros PR to be merged, and then we can return to this one.

[joshk]

Sorry for the delay in merging in the Macros PR.

Ping me when your ready for me to review this again.

[taras-tyshko]

@joshk thanks for all you work, that's awesome to see the support from your side.
I did a rebase and you can review PR again. Thanks

[taras-tyshko]

@joshk I’ve updated the branch with the latest changes. Could you please take another look at the PR when you have a chance? Thanks!

[nshoes]

Is this really needed for a test file? Do other tests no need this? 🤔

[nshoes]

This LGTM! @joshk do you have any other thoughts before we merge?