VariableVince 0dc8fbf129 Fix inverse annexation (#3448)
## Description:

An inverse annexation could happen where the small player (even with
0,01% tiles owned) could fully annex the large player.

**TL;DR:** basically wrong use of calculateBoundingBox in
surroundedBySamePlayer, feeding it all bordertiles, making enemyBox far
bigger than it actually was in some cases. Which resulted in enemyBox of
small player with two small clusters at some distance from each other,
being seen as inscribing the largest cluster of the bigger player. While
that largest cluster is actually the border tiles of the bigger player
surrounding the main cluster of the small player. Instead of an
annexation of small by bigger, small would incorrectly annex bigger
completely.

**Situation:** bigger player fully surrounds main cluster of smaller
player. Those border tiles are also the largest cluster of the bigger
player, for which surroundedBySamePlayer is called.
SurroundedBySamePlayer finds the small player as the only bordering
enemy of this cluster. Then it needs to check which of the two players
is surrounded by the other one. EnemyBox uses calculateBoundingBox with
all border tiles of the small player as argument. The small player also
has at least one seperate cluster elsewhere, could be on another island,
which count as border tiles too. The enemyBox from the main cluster of
the small player to the seperate cluster elsewhere, can be huge. Now
inscribed() is called and it determines that largest cluster box of the
bigger player (which was in fact calculated correctly, also making use
of calculateBoundingBox) is surrounded by the bigger enemyBox. And so
the small surrounded player fully annexes the bigger player.

**Fix:** instead of a global enemyBox, we only need the localEnemyBox
that touches the largest cluster of the bigger player. With that,
inscribed() can correctly conclude that largest cluster box surrounds
the localEnemyBox. As a matter of fact isSurrounded() already used the
same method to calculate its enemyBox as introduced by @scamiv for v30:
https://github.com/openfrontio/OpenFrontIO/pull/3127/changes#diff-fb1101a2b50dd7c353d082ff7a3351cff5469b8249b3ebca91c10573a3dfaaf1

- Change in PlayerExecution
- Added test NoInverseAnnexation.test.ts, which fails before and passes
after the fix

The bug was introduced in this commit 10 months ago:
https://github.com/openfrontio/OpenFrontIO/commit/c4381a9ad3828b06764ab1a21fc1514e37aacfd7

It has probably led to some weird annexations happening since then. The
bug could seemingly happen on any map. But was noted recently a few
times on square islands (Sierpinski) or maps (The Box/The Alps), where
the circumstances probably highten the chances of the bug occuring.

**Bug reports:**

https://discord.com/channels/1359946986937258015/1481916231689703477/1481916231689703477

https://discord.com/channels/1359946986937258015/1481916231689703477/1481963273367851030

https://discord.com/channels/1284581928254701718/1479993924432171008/1479995658302652496

https://discord.com/channels/1284581928254701718/1479993924432171008/1481865495492956182
https://discord.com/channels/1284581928254701718/1483047153571201034

**BEFORE:**

https://github.com/user-attachments/assets/4440182b-f696-45cf-bb01-b10159df8763

**AFTER**, on the same replay but with the bugfix:

https://github.com/user-attachments/assets/5f461ab2-eb62-4cc3-ae07-e2224adbbc6a

## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [x] I have added relevant tests to the test directory
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced

## Please put your Discord username so you can be contacted if a bug or
regression is found:

tryout33
2026-03-17 11:15:18 -07:00
2025-06-22 08:14:08 -07:00
2025-09-30 11:13:32 -07:00
2026-03-17 11:15:18 -07:00
2026-03-17 11:15:18 -07:00
2025-05-15 23:09:39 -04:00
2025-03-06 15:50:29 -08:00
2025-05-15 23:09:39 -04:00
2026-01-21 10:00:55 -08:00
2026-03-05 20:43:34 -08:00
2026-01-08 13:34:18 -08:00
2026-03-13 18:32:29 -07:00
2026-03-13 18:32:29 -07:00

OpenFrontIO Logo

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.

CI Crowdin CLA assistant License: AGPL v3 Assets: CC BY-SA 4.0

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

  1. Clone the repository

    git clone https://github.com/openfrontio/OpenFrontIO.git
    cd OpenFrontIO
    
  2. Install dependencies

    npm run inst
    

    Do NOT use npm install nor npm i but instead use our npm run inst. It runs the safer npm ci --ignore-scripts to install dependencies exactly according to the versions in package-lock.json and 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=true in 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 gitCommit value via https://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 - Shared game logic
  • /src/server - Backend game server
  • /resources - Static assets (images, maps, etc.)

🤝 Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

  1. Request to join the development Discord.
  2. Fork the repository
  3. Create your feature branch (git checkout -b amazing-feature)
  4. Commit your changes (git commit -m 'Add some amazing feature')
  5. Push to the branch (git push origin amazing-feature)
  6. Open a Pull Request

🌐 Translation

Translators are welcome! Please feel free to help translate into your language. How to help?

  1. Join the translation Discord
  2. Go to the project's Crowdin translation page: https://crowdin.com/project/openfront-mls
  3. Login if you already have an account / Sign up if you don't have one
  4. Join the project
  5. Select the language you want to translate in. If your language isn't on the list, click the "Request New Language" button and enter the language you want added there.
  6. Translate the strings

Feel free to ask questions in the translation Discord server!

Project Governance

  • The project maintainer (evan) has final authority on all code changes and design decisions
  • All pull requests require maintainer approval before merging
  • The maintainer reserves the right to reject contributions that don't align with the project's vision or quality standards

Contribution Path for New Contributors

To ensure code quality and project stability, we use a progressive contribution system:

  1. New Contributors: Limited to UI improvements and small bug fixes only

    • This helps you become familiar with the codebase
    • UI changes are easier to review and less likely to break core functionality
    • Small, focused PRs have a higher chance of being accepted
  2. Established Contributors: After several successful PRs and demonstrating understanding of the codebase, you may work on more complex features

  3. Core Contributors: Only those with extensive experience with the project may modify critical game systems

How to Contribute Successfully

  1. Before Starting Work:

    • Open an issue describing what you want to contribute
    • Wait for maintainer feedback before investing significant time
    • Small improvements can proceed directly to PR stage
  2. Code Quality Requirements:

    • All code must be well-commented and follow existing style patterns
    • New features should not break existing functionality
    • Code should be thoroughly tested before submission
    • All code changes in src/core MUST be tested.
  3. Pull Request Process:

    • Keep PRs focused on a single feature or bug fix
    • Include screenshots for UI changes
    • Describe what testing you've performed
    • Be responsive to feedback and requested changes
  4. Testing Requirements:

    • Verify your changes work as expected
    • Test on multiple systems/browsers if applicable
    • Document your testing process in the PR

Communication

  • Be respectful and constructive in all project interactions
  • Questions are welcome, but please search existing issues first
  • For major changes, discuss in an issue before starting work

Final Notes

Remember that maintaining this project requires significant effort. The maintainer appreciates your contributions but must prioritize long-term project health and stability. Not all contributions will be accepted, and that's okay.

Thank you for helping make OpenFront better!

S
Description
Languages
TypeScript 91.3%
GLSL 2.6%
JavaScript 1.9%
HTML 1.7%
CSS 1%
Other 1.5%