nix-source-info

nix-source-info makes a Nix flake's source metadata available to a Rust program at runtime. It uses ver-stub to inject the flake's sourceInfo JSON into already-built binaries, so changing version metadata does not require recompiling them.

The repository provides:

• the nix-source-info Rust crate, whose SourceInfo::get() method exposes the revision, dirty state, timestamp, NAR hash, store path, and related metadata;
• the Nix flake helper lib.patchSourceInfo, which copies a package and patches every executable in its bin directory with that metadata.

Usage

Read the metadata from Rust:

use nix_source_info::SourceInfo;

if let Some(info) = SourceInfo::get() {
    println!("{} ({})", info.rev8(), info.timestamp());
}

Then wrap the program's Nix package with the helper, passing the source flake's sourceInfo:

source-info.lib.patchSourceInfo pkgs self.sourceInfo my-package

SourceInfo::get() returns None when the binary has not been patched.