---
format: "aidr-story-markdown/v1"
id: "72035a6bd1e24a1a5e273de1bd66fabe5c8e8e5fe0a1fdab41ef36c29b6e8653"
canonical_url: "https://aidr.today/72035a6b?lang=en"
title: "Nix wrote half of my debugger"
lang: "en"
requested_lang: "en"
available_langs: ["en","vi"]
translation_fallback: null
fallback_fields: []
published_at: "2026-10-08T10:47:08.000Z"
category: "Tools"
topics: ["coding","devtools"]
source_urls: ["https://fzakaria.com/2026/10/07/nix-wrote-half-of-my-debugger","https://lobste.rs/s/bwmolc/nix_wrote_half_my_debugger"]
summary: "The author developed a deterministic virtual machine called Rewind VM that reproduces Nix build race conditions by treating each run as a pure function of its inputs, and the tool has since gained features like a source panel, stack frames, and thread lanes that help identify exact steps where race conditions occur."
---

# Nix wrote half of my debugger

> [Open the canonical story](<https://aidr.today/72035a6b?lang=en>)

**Published:** 2026-10-08T10:47:08.000Z
**Category:** Tools
**Topics:** coding, devtools

## Summary

The author developed a deterministic virtual machine called Rewind VM that reproduces Nix build race conditions by treating each run as a pure function of its inputs, and the tool has since gained features like a source panel, stack frames, and thread lanes that help identify exact steps where race conditions occur\.

## Sources

- [Story source](<https://fzakaria.com/2026/10/07/nix-wrote-half-of-my-debugger>)
- [Discussion](<https://lobste.rs/s/bwmolc/nix_wrote_half_my_debugger>)