## Problem Fixes #4284. When you build a factory in an area with **no pre-existing factory** (e.g. just a city nearby), no rail ghost preview appeared — even though building the factory *would* lay rail lines connecting it to that city. ## Root cause `computeGhostRailPaths` in `RailNetworkImpl.ts` had two factory-hostile assumptions: 1. It bailed out early unless a `Factory` was already in range (`hasUnitNearby(..., UnitType.Factory)`). 2. It only matched neighbors that were *already* train stations (`findStation(...)` → skipped if null). But a **Factory** always becomes a station itself and *promotes* nearby City/Port/Factory into the rail network (see `FactoryExecution`). So it needs no pre-existing factory, and its neighbors won't be stations yet on first build. A **City/Port** only joins the network when a factory already exists (`CityExecution`/`PortExecution`) — so their behavior is correctly left unchanged. ## Fix - Skip the "factory must be nearby" gate when the placed unit is itself a `Factory`. - For a factory build, pathfind to nearby City/Port/Factory even if they aren't stations yet. City/Port keep connecting only to existing stations. ## Tests Added two cases to `RailNetwork.test.ts` (factory connects with no pre-existing factory; city still doesn't without one). All 25 tests pass. ## Note on scope As @Katokoda noted on the issue, a fully build-exact preview (neighboring structures also connecting to *each other*, merging existing networks, etc.) is larger and order-dependent. This PR resolves the reported bug — the initial factory now shows its rail ghost — and leaves the exact-match cascade as a separate follow-up. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
OpenFront.io is an online real-time strategy game focused on territorial control and alliance building. Players compete to expand their territory, build structures, and form strategic alliances in various maps based on real-world geography.
This is a fork/rewrite of WarFront.io. Credit to https://github.com/WarFrontIO.
License
OpenFront source code is licensed under the GNU Affero General Public License v3.0
Current copyright notices appear in:
- Footer: "© OpenFront and Contributors"
- Loading screen: "© OpenFront and Contributors"
Modified versions must preserve these notices in reasonably visible locations.
See the LICENSE for complete requirements.
For asset licensing, see LICENSE-ASSETS.
For license history, see LICENSING.md.
🌟 Features
- Real-time Strategy Gameplay: Expand your territory and engage in strategic battles
- Alliance System: Form alliances with other players for mutual defense
- Multiple Maps: Play across various geographical regions including Europe, Asia, Africa, and more
- Resource Management: Balance your expansion with defensive capabilities
- Cross-platform: Play in any modern web browser
📋 Prerequisites
- npm (v10.9.2 or higher)
- A modern web browser (Chrome, Firefox, Edge, etc.)
🚀 Installation
-
Clone the repository
git clone https://github.com/openfrontio/OpenFrontIO.git cd OpenFrontIO -
Install dependencies
npm run instDo NOT use
npm installnornpm ibut instead use ournpm run inst. It runs the safernpm ci --ignore-scriptsto install dependencies exactly according to the versions inpackage-lock.jsonand doesn't run scripts. This can prevent being hit by a supply chain attack.
🎮 Running the Game
Development Mode
Run both the client and server in development mode with live reloading:
npm run dev
This will:
- Start the webpack dev server for the client
- Launch the game server with development settings
- Open the game in your default browser (to disable this behavior, set
SKIP_BROWSER_OPEN=truein your environment)
Client Only
To run just the client with hot reloading:
npm run start:client
Server Only
To run just the server with development settings:
npm run start:server-dev
Connecting to staging or production backends
Sometimes it's useful to connect to production servers when replaying a game, testing user profiles, purchases, or login flow.
To replay a production game, make sure you're on the same commit that the game you want to replay was executed on, you can find the
gitCommitvalue viahttps://api.openfront.io/game/[gameId]. Unfinished games cannot be replayed on localhost.
To connect to staging api servers:
npm run dev:staging
To connect to production api servers:
npm run dev:prod
🛠️ Development Tools
-
Format code:
npm run format -
Lint code:
npm run lint -
Lint and fix code:
npm run lint:fix -
Testing
npm test
🏗️ Project Structure
/src/client- Frontend game client/src/core- Deterministic game simulation/src/server- Backend game server/resources- Static assets (images, maps, etc.)
🤝 Contributing
Contributions and translations are welcome! See CONTRIBUTING.md for the workflow, the approved-issue process, project governance, and translation info.