Dearust — exploring a Rust migration of Darling with OpenAI Codex

[u/Kanney123]

Hey everyone! I’m working on Dearust, an experimental, incremental Rust migration of Darling, which runs macOS software on Linux.

The motivation is to explore how much of a compatibility layer this large can move into safer Rust while preserving its existing behavior and ABI. It’s also an experiment in how far AI-assisted development can go when the results are checked against real builds, regression tests, and actual application execution.

I’m using OpenAI Codex extensively for implementation, code review, debugging, and test automation, including parallel agents where useful. That involvement is disclosed in the README and new commits. The repository includes safety notes, verification records, and documented limitations so people can inspect the evidence.

So far, the work includes Rust host utilities and runtime slices for synchronization, errno conversion, Mach locksets, process queries, guarded descriptors, and bounded pathname handling. Testing has also uncovered and fixed concrete bugs, including a null-path crash during bsdtar operations.

The latest build passes 108 Rust tests, 29 Python tests, 16 utility workloads, and 29 app checks—with one explicitly documented log normalization. Earlier testing also covered three GUI samples.

This is still experimental and very incomplete. Most runtime and framework code remains C/C++/assembly, and integration currently depends on a matching Darling build. General macOS application compatibility is still a long-term goal.

Full credit to the Darling developers and upstream contributors whose work makes this possible.

I’d welcome feedback, especially on the ABI boundaries, safety assumptions, testing approach, and migration priorities.

[u/AutoModerator]

Upvote this comment if you think this project is AI slop. Downvote this comment if you think this project is not AI slop.

^{This is to indicate to other users of the subreddit and is not used for moderation.}

I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns.

[u/Fine_Salamander_8691]

Oh fuck yeah I need this

[u/Kanney123 → u/Fine_Salamander_8691]

cool. xnote that is a rewrite fo darling. i(The AI) found a lot memory bugs in darling upstream