Port upstream earcut changes to C# (f183d7a) — 2026-07-03

[github-actions]

Upstream Sync Task

@Copilot please port the upstream changes listed below to C# and open a pull request.

New commits have been pushed to mapbox/earcut since the last sync.

Previous synced commit: d417600
New upstream commit: f183d7a
Full diff: mapbox/earcut@d417600...f183d7a

Upstream commits to port

• f183d7a 3.2.3
• d8787b1 minor readme updates
• 3ed046b improve flip bound (faster COMMIT_LIST termination guaranteed)

What to port

Please port all upstream changes to C# and open a pull request. Follow the PORTING_GUIDE.md for language mapping conventions.

Key files to check in the upstream diff:

• src/earcut.js → port any algorithm changes to src/Earcut/Earcut.cs
• test/fixtures/*.json → copy any new/changed fixtures to test/Earcut.Tests/fixtures/
• test/expected.json → update test/Earcut.Tests/expected.json to match

After porting:

1. Run dotnet test and ensure all tests pass
2. Update PORTING_GUIDE.md if new language patterns were introduced