{
  "id": 13540098,
  "title": "Nix wrote half of my debugger",
  "url": "https://urgent.news/2026/10/09/nix-wrote-half-of-my-debugger",
  "topic": "tech",
  "section": "Tech",
  "published": "2026-10-09T07:29:08.000Z",
  "source": {
    "name": "Hacker News",
    "slug": "hacker-news",
    "url": "https://fzakaria.com/2026/10/07/nix-wrote-half-of-my-debugger"
  },
  "original_language": "en",
  "account": "Nix has developed a debugger for its deterministic VM, Rewind. The debugger is integrated with the source panel, stack frames, bookmarks, and thread lanes. It leverages Nix's ability to access the exact inputs of a program, debug symbols, sources, and libraries, as well as the derivation that packages are built from. Rewind's VM runs on a single CPU, which helps in isolating race conditions. It runs the build multiple times with different schedules, narrowing down the failure to a specific step. The debugger allows users to see the source of the program at the playhead, stack frames, and even execute gdb commands on a fork of the run. If the source is not enough, users can use rewind gdb to inspect the program's state. Rewind also provides a Compare tab that shows the differences between two runs, helping to identify the exact step where a race condition occurs.",
  "summary": null,
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}