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Nix, the purely functional package manager
40beb50e8f
Adds buildStorePathGraphFromScan() to bridge the generic DependencyGraph
infrastructure with Nix's store path reference scanning. This enables
building annotated dependency graphs that track which files create which
dependencies.
## New API: buildStorePathGraphFromScan()
**Purpose**: Convert file-level scan results into a StorePath-level graph
**How it works**:
1. Calls scanForReferencesDeep() to find which files contain references
2. For each file that references another store path:
- Adds edge: rootStorePath → referencedStorePath
- Attaches FileListEdgeProperty with the file path
3. Returns DependencyGraph<StorePath, FileListEdgeProperty>
**Key benefit**: The graph carries file-level provenance. When you see
an edge A→B, you can query which files in A reference B. Essential for:
- why-depends output showing exact file locations
- Future: detailed cycle error messages
## API Changes
**scanForReferencesDeep() callback signature**:
```cpp
// Before: std::function<void(FileRefScanResult)>
// After: std::function<void(const FileRefScanResult &)>
```
Pass by const-ref to avoid copying large result structures.
## Usage Example
```cpp
auto graph = buildStorePathGraphFromScan(
*accessor,
CanonPath("/nix/store/abc-foo"),
storePathAbc,
candidateRefs
);
// Query file annotations
auto edgeProp = graph.getEdgeProperty(storePathAbc, storePathDef);
// edgeProp->files contains files that created this edge
```
## Implementation Details
- Uses DependencyGraph's edge properties feature
- FileListEdgeProperty defined in dependency-graph.hh
- Merges duplicate edges (multiple files → same path)
- Debug logging for discovered edges
- Zero overhead if file-level detail not needed
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|---|---|---|
| .github | ||
| ci/gha | ||
| contrib | ||
| doc/manual | ||
| maintainers | ||
| misc | ||
| nix-meson-build-support | ||
| packaging | ||
| scripts | ||
| src | ||
| tests | ||
| .clang-format | ||
| .clang-tidy | ||
| .dir-locals.el | ||
| .editorconfig | ||
| .git-blame-ignore-revs | ||
| .gitignore | ||
| .shellcheckrc | ||
| .version | ||
| CITATION.cff | ||
| CONTRIBUTING.md | ||
| COPYING | ||
| default.nix | ||
| docker.nix | ||
| flake.lock | ||
| flake.nix | ||
| HACKING.md | ||
| meson.build | ||
| meson.format | ||
| meson.options | ||
| README.md | ||
| shell.nix | ||
Nix
Nix is a powerful package manager for Linux and other Unix systems that makes package management reliable and reproducible. Please refer to the Nix manual for more details.
Installation and first steps
Visit nix.dev for installation instructions and beginner tutorials.
Full reference documentation can be found in the Nix manual.
Building and developing
Follow instructions in the Nix reference manual to set up a development environment and build Nix from source.
Contributing
Check the contributing guide if you want to get involved with developing Nix.
Additional resources
Nix was created by Eelco Dolstra and developed as the subject of his PhD thesis The Purely Functional Software Deployment Model, published 2006. Today, a world-wide developer community contributes to Nix and the ecosystem that has grown around it.
- The Nix, Nixpkgs, NixOS Community on nixos.org
- Official documentation on nix.dev
- Nixpkgs is the largest, most up-to-date free software repository in the world
- NixOS is a Linux distribution that can be configured fully declaratively
- Discourse
- Matrix: #users:nixos.org for user support and #nix-dev:nixos.org for development
License
Nix is released under the LGPL v2.1.