# editor: Add language detection for untitled buffers \(\#61201\) · gitcafe/zed [View on GitCafe](https://git.cafe/gitcafe/zed/commit/690c7fac64a4ed013ad92d8794333a6548858e2f) Repository: [gitcafe/zed](https://git.cafe/gitcafe/zed) Visibility: public Requested revision: 690c7fac64a4ed013ad92d8794333a6548858e2f Requested commit: 690c7fac64a4ed013ad92d8794333a6548858e2f Commit: 690c7fac64a4ed013ad92d8794333a6548858e2f Tree: 7b54a94a2f9914547edb0657e93ce2eda68a2c57 Author: ᴀᴍᴛᴏᴀᴇʀ Committer: GitHub ## Message ``` editor: Add language detection for untitled buffers (#61201) # Objective Closes #4868. Untitled buffers start as Plain Text and require users to select a language manually before receiving syntax highlighting. Add lightweight automatic language detection for code entered or pasted into untitled buffers. ## Solution This builds on [Max Stevens's earlier language-detection work](https://github.com/zed-industries/zed/pull/43057), replacing Magika with [Betlang](https://github.com/DioxusLabs/betlang). While researching smaller and faster alternatives to Magika, I came across Betlang, a recently introduced language detection library developed by DioxusLabs for dioxus-code. The fact that it comes from DioxusLabs gave me more confidence in evaluating this relatively new dependency for Zed. Betlang embeds an approximately 50 KB model, is MIT-licensed, and depends only on `fearless_simd`, making it well suited to Zed's cross-platform embedding requirements. Detection runs on the background executor with bounded input sampling. It is restricted to untitled buffers, skips content shorter than 20 bytes, and requires at least 50% confidence. These limits have worked well in local testing. In release builds on Linux with an Intel Core i5-13600KF, the `betlang::detect` call alone typically completes within 3 ms when processing the maximum sampled input. ## Testing I added a test for language detection in untitled buffers that covers both manually entered and pasted content. The test passes successfully. I also manually tested the feature to verify that the overall experience works well. ## Self-Review Checklist: - [x] I've reviewed my own diff for quality, security, and reliability - [x] Unsafe blocks (if any) have justifying comments - [x] The content adheres to Zed's UI standards ([UX/UI](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist) and [icon](https://github.com/zed-industries/zed/blob/main/crates/icons/README.md) guidelines) - [x] Tests cover the new/changed behavior - [x] Performance impact has been considered and is acceptable ## Showcase https://github.com/user-attachments/assets/96e28ad7-2968-4325-9aff-37fe813a2da7 --- Release Notes: - Added automatic language detection for untitled buffers. --------- Co-authored-by: Max Stevens ``` ## Parents - [339d96b5a81a8fd8434b766e501c6a4c27f59b60](https://git.cafe/gitcafe/zed/commit/339d96b5a81a8fd8434b766e501c6a4c27f59b60?format=markdown) [Source at this commit](https://git.cafe/gitcafe/zed/tree/690c7fac64a4ed013ad92d8794333a6548858e2f?format=markdown)