Bernardo Meurer
a53ede53dc
buildRustCrate passes `--remap-path-prefix=$NIX_BUILD_TOP=/` so the sandbox build directory is not embedded in compiled artifacts. The resulting source path is `/$sourceRoot/src/...` — which works out to `/<crateName>-<version>/src/...` only because fetchCrate happens to unpack to a directory named after the crate. When `src` is supplied directly — `lib.fileset.toSource` (always `source`), `lib.cleanSource ./.`, a flake's `self`, or any `<hash>-source` store path — stdenv unpacks to `$NIX_BUILD_TOP/source/`, so every such crate ends up with `/source/src/lib.rs`. The crate identity is gone from panic backtraces, `file!()` expansions, debuginfo, and llvm-cov coverage maps. Workspace builds via crate2nix that source each member with a fileset see all members collapse to the same prefix, making per-crate coverage and backtrace attribution impossible without a per-crate remap override. Add a second, more specific remap of `$NIX_BUILD_TOP/$sourceRoot` to `/<crateName>-<version>`. rustc applies `--remap-path-prefix` flags last-match-wins, so this prefix wins for everything under the source root — which in a buildRustCrate build is effectively everything that would otherwise embed a sandbox path, including `OUT_DIR` (placed at `$sourceRoot/target/build/` by configure-crate.nix). The broader `$NIX_BUILD_TOP=/` remap stays as a fallback for any path outside `$sourceRoot`. This is safe with respect to the original remap's purpose: - Reproducibility: still maps the per-build sandbox path to a fixed, build-independent string. `crateName` and `version` are already derivation inputs, so the result is deterministic. - Closure size: still no store paths in the embedded strings. - fetchCrate sources: `$sourceRoot` is `<crateName>-<version>` there, so the new remap rewrites `/<crateName>-<version>` to itself — the output is byte-for-byte identical. Only custom-`src` crates change, and they change from a degenerate `/source/...` to the same shape fetchCrate crates already had. - The remap only affects path *strings* embedded in output (DWARF `DW_AT_comp_dir`/`DW_AT_name`, `file!()`, `Location::file()`, LLVM coverage filename tables). It does not change which files are read or compiled. Users who depend on the old `/source/...` prefix can restore it via `extraRustcOpts`, which is appended after these flags and therefore wins under last-match-wins.
Nixpkgs is a collection of over 120,000 software packages that can be installed with the Nix package manager. It also implements NixOS, a purely-functional Linux distribution.
Manuals
- NixOS Manual - how to install, configure, and maintain a purely-functional Linux distribution
- Nixpkgs Manual - contributing to Nixpkgs and using programming-language-specific Nix expressions
- Nix Package Manager Manual - how to write Nix expressions (programs), and how to use Nix command line tools
Community
- Discourse Forum
- Matrix Chat
- Official wiki
- Community-maintained list of ways to get in touch (Discord, Telegram, IRC, etc.)
Other Project Repositories
The sources of all official Nix-related projects are in the NixOS organization on GitHub. Here are some of the main ones:
- Nix - the purely functional package manager
- NixOps - the tool to remotely deploy NixOS machines
- nixos-hardware - NixOS profiles to optimize settings for different hardware
- Nix RFCs - the formal process for making substantial changes to the community
- NixOS homepage - the NixOS.org website
- hydra - our continuous integration system
- NixOS Branding - NixOS branding
Continuous Integration and Distribution
Nixpkgs and NixOS are built and tested by our continuous integration system, Hydra.
- Continuous package builds for unstable/master
- Continuous package builds for the NixOS 25.11 release
- Tests for unstable/master
- Tests for the NixOS 25.11 release
Artifacts successfully built with Hydra are published to cache at https://cache.nixos.org/. When successful build and test criteria are met, the Nixpkgs expressions are distributed via Nix channels.
Contributing
Nixpkgs is among the most active projects on GitHub. While thousands of open issues and pull requests might seem like a lot at first, it helps to consider it in the context of the scope of the project. Nixpkgs describes how to build tens of thousands of pieces of software and implements a Linux distribution. The GitHub Insights page gives a sense of the project activity.
Community contributions are always welcome through GitHub Issues and Pull Requests.
For more information about contributing to the project, please visit the contributing page.
Donations
The infrastructure for NixOS and related projects is maintained by a nonprofit organization, the NixOS Foundation. To ensure the continuity and expansion of the NixOS infrastructure, we are looking for donations to our organization.
You can donate to the NixOS Foundation through SEPA bank transfers or by using Open Collective:
License
Nixpkgs is licensed under the MIT License.
Note
MIT license does not apply to the packages built by Nixpkgs, merely to the files in this repository (the Nix expressions, build scripts, NixOS modules, etc.). It also might not apply to patches included in Nixpkgs, which may be derivative works of the packages to which they apply. The aforementioned artifacts are all covered by the licenses of the respective packages.