Contributing to Radarr

[Starosdev]

Contributing

Thank you for your interest in contributing to Radarr! This is an actively maintained fork of the original Radarr/Radarr project.

Before You Start

• Check GitHub Issues for existing issues and planned work
• For bug reports or feature requests, please open a GitHub issue first
• For large changes, please discuss your approach in an issue before starting work

Branch Workflow

We use a Gitflow-style workflow:

• master - Production-ready code (protected)
• develop - Integration branch for features
• feature/* - New features
• fix/* - Bug fixes
• hotfix/* - Urgent production fixes

Creating a PR

1. Fork the repository and create your branch from develop
2. Make meaningful commits, or squash them
3. Ensure all tests pass
4. Submit a PR to develop (never master, unless it is a hotfix)

Code Style

• No emojis in code, commits, comments, or documentation
• Follow existing code patterns and formatting
• Backend: StyleCop analyzers enforced, 4-space indentation, var preferred, _camelCase for private fields
• Frontend: ESLint + Prettier (2-space indentation), StyleLint for CSS

Run linting before submitting frontend changes:

yarn lint --fix
yarn stylelint-linux   # macOS/Linux

Project Structure

Radarr is a monorepo containing:

• C#/.NET 8.0 Backend (API, domain logic, data layer)
• React/TypeScript Frontend (SPA with Redux and SignalR)

The codebase uses the legacy NzbDrone namespace from its predecessor project. Project directories use NzbDrone.* but .csproj files are named Radarr.*.

Development Setup

Tools Required

• .NET SDK 8.0 (see global.json for exact version)
• Node.js 20.x (Volta-managed)
• Yarn 1.22.x (included with Node 20+ via corepack enable)
• Git
• Visual Studio 2022+, Rider, or VS Code

Node 20.x is required. The application will not run on older versions (18.x, 16.x) or on 21.x due to dependency issues.

Getting Started

1. Fork the repository
2. Clone your fork
3. Build and run (see below)

Building the Frontend

yarn install --frozen-lockfile
yarn start                        # Dev watch mode
yarn build                        # Production build

Building the Backend

Visual Studio / Rider

1. Open src/Radarr.sln
2. Set startup project to Radarr.Console, framework to net8.0
3. Build the solution
4. Run/Debug
5. Open http://localhost:7878

Command Line

# Clean
dotnet clean src/Radarr.sln -c Debug

# Restore and build
dotnet msbuild -restore src/Radarr.sln -p:Configuration=Debug -p:Platform=Posix -t:PublishAllRids

# Run from output
./_output/Radarr

Running Tests

Radarr uses NUnit for its test suite. Test assemblies are output to _tests/.

# Unit tests
./test.sh Linux Unit Test
./test.sh Mac Unit Test

# Integration tests
./test.sh Linux Integration Test

# With coverage
./test.sh Linux Unit Coverage

# Specific test project
dotnet test src/NzbDrone.Core.Test/Radarr.Core.Test.csproj

# Specific test by name
dotnet test src/NzbDrone.Core.Test/Radarr.Core.Test.csproj --filter "FullyQualifiedName~TestClassName"

We encourage writing unit tests for any backend code changes. We currently require 80% coverage on new code when submitting a PR.

Contributing Code

• If you're adding a feature already listed in Issues, comment on it so work is not duplicated
• Rebase from develop, do not merge
• One feature/bug fix per pull request
• Add tests (unit/integration)
• Commit with unix line endings
• Use 4 spaces instead of tabs (backend), 2 spaces (frontend)
• Commits should use New: or Fixed: prefixes for non-maintenance changes
• Feel free to open a draft PR before work is complete so we can provide early feedback

Translation

Radarr uses a self-hosted Weblate instance for translations. Translation files are stored at src/NzbDrone.Core/Localization.

The English translation (en.json) is the source for all other translations and is managed in the GitHub repo.

Adding Translation Strings

Backend

private readonly ILocalizationService _localizationService;

public IndexerCheck(ILocalizationService localizationService)
{
    _localizationService = localizationService;
}

var translated = _localizationService.GetLocalizedString("IndexerHealthCheckNoIndexers");

Frontend

import translate from 'Utilities/String/translate';

<div>
  {translate('UnableToAddANewIndexerPleaseTryAgain')}
</div>

PRs for translation of log messages will not be accepted.