nixops4 · Ericson2314 · Dec 6, 2025
diff --git a/Cargo.lock b/Cargo.lock
diff --git a/Cargo.toml b/Cargo.toml
@@ -1,6 +1,11 @@
 [workspace]
 members = [
-    "nix-bindings-bindgen-raw",
+    "nix-bindings-bdwgc-sys",
+    "nix-bindings-util-sys",
+    "nix-bindings-store-sys",
+    "nix-bindings-expr-sys",
+    "nix-bindings-fetchers-sys",
+    "nix-bindings-flake-sys",
     "nix-bindings-expr",
     "nix-bindings-fetchers",
     "nix-bindings-flake",

diff --git a/flake.nix b/flake.nix
@@ -29,10 +29,7 @@
           {
             _file = ./flake.nix;
             options.perSystem = flake-parts-lib.mkPerSystemOption (
-              { config, pkgs, ... }:
-              let
-                cfg = config.nix-bindings-rust;
-              in
+              { pkgs, ... }:
               {
                 options.nix-bindings-rust = {
                   nixPackage = lib.mkOption {
@@ -49,10 +46,25 @@
                       A module to load into your nix-cargo-integration
                       [`perSystem.nci.projects.<name>.depsDrvConfig`](https://flake.parts/options/nix-cargo-integration.html#opt-perSystem.nci.projects._name_.depsDrvConfig) or similar such options.
 
+                      This provides common build configuration (pkg-config, libclang, etc.) but you must
+                      add the specific Nix C libraries your crates need to `buildInputs`:
+                      - `nix-bindings-util-sys` needs `nix-util-c`
+                      - `nix-bindings-store-sys` needs `nix-store-c`
+                      - `nix-bindings-expr-sys` needs `nix-expr-c`
+                      - `nix-bindings-fetchers-sys` needs `nix-fetchers-c` (Nix >= 2.29)
+                      - `nix-bindings-flake-sys` needs `nix-flake-c`
+                      - `nix-bindings-bdwgc-sys` needs `boehmgc`
+
                       Example:
                       ```nix
-                      perSystem = perSystem@{ config, ... }: {
-                        nci.projects."my_project".depsDrvConfig = perSystem.config.nix-bindings-rust.nciBuildConfig;
+                      perSystem = perSystem@{ config, pkgs, ... }: {
+                        nci.projects."my_project".depsDrvConfig = {
+                          imports = [ perSystem.config.nix-bindings-rust.nciBuildConfig ];
+                          mkDerivation.buildInputs = [
+                            perSystem.config.nix-bindings-rust.nixPackage.libs.nix-store-c
+                            # ... add other libs as needed
+                          ];
+                        };
                       }
                       ```
                     '';
@@ -64,22 +76,7 @@
                       buildInputs = [
                         # stdbool.h
                         pkgs.stdenv.cc
-                      ]
-                      ++ (
-                        if cfg.nixPackage ? libs then
-                          let
-                            l = cfg.nixPackage.libs;
-                          in
-                          [
-                            l.nix-expr-c
-                            l.nix-store-c
-                            l.nix-util-c
-                            l.nix-fetchers-c or null # Nix >= 2.29
-                            l.nix-flake-c
-                          ]
-                        else
-                          [ cfg.nixPackage ]
-                      );
+                      ];
                       nativeBuildInputs = [
                         pkgs.pkg-config
                       ];

diff --git a/nci.nix b/nci.nix
@@ -2,8 +2,24 @@
   perSystem =
     {
       config,
+      pkgs,
       ...
     }:
+    let
+      cfg = config.nix-bindings-rust;
+      nixLibs =
+        if cfg.nixPackage ? libs then
+          cfg.nixPackage.libs
+        else
+          # Fallback for older Nix versions without split libs
+          {
+            nix-util-c = cfg.nixPackage;
+            nix-store-c = cfg.nixPackage;
+            nix-expr-c = cfg.nixPackage;
+            nix-fetchers-c = cfg.nixPackage;
+            nix-flake-c = cfg.nixPackage;
+          };
+    in
     {
       # https://flake.parts/options/nix-cargo-integration
       nci.projects.nix-bindings = {
@@ -38,12 +54,46 @@
               echo "experimental-features = ca-derivations flakes" > "$NIX_CONF_DIR/nix.conf"
 
               # Init ahead of time, because concurrent initialization is flaky
-              ${config.nix-bindings-rust.nixPackage}/bin/nix-store --init
+              ${cfg.nixPackage}/bin/nix-store --init
 
               echo "Store initialized."
             '';
           };
         };
       };
+
+      # Per-crate configuration: only provide the specific Nix libs each crate needs
+      # FIXME should use propagatedBuildInputs
+      nci.crates.nix-bindings-bdwgc-sys.drvConfig.mkDerivation.buildInputs = [
+        pkgs.boehmgc
+      ];
+      nci.crates.nix-bindings-util-sys.drvConfig.mkDerivation.buildInputs = [
+        nixLibs.nix-util-c
+      ];
+      nci.crates.nix-bindings-util.drvConfig.mkDerivation.buildInputs =
+        config.nci.crates.nix-bindings-util-sys.drvConfig.mkDerivation.buildInputs;
+      nci.crates.nix-bindings-store-sys.drvConfig.mkDerivation.buildInputs =
+        config.nci.crates.nix-bindings-util-sys.drvConfig.mkDerivation.buildInputs
+        ++ [ nixLibs.nix-store-c ];
+      nci.crates.nix-bindings-store.drvConfig.mkDerivation.buildInputs =
+        config.nci.crates.nix-bindings-store-sys.drvConfig.mkDerivation.buildInputs;
+      nci.crates.nix-bindings-expr-sys.drvConfig.mkDerivation.buildInputs =
+        config.nci.crates.nix-bindings-store-sys.drvConfig.mkDerivation.buildInputs
+        ++ [
+          nixLibs.nix-expr-c
+          pkgs.boehmgc
+        ];
+      nci.crates.nix-bindings-expr.drvConfig.mkDerivation.buildInputs =
+        config.nci.crates.nix-bindings-expr-sys.drvConfig.mkDerivation.buildInputs;
+      nci.crates.nix-bindings-fetchers-sys.drvConfig.mkDerivation.buildInputs =
+        config.nci.crates.nix-bindings-expr-sys.drvConfig.mkDerivation.buildInputs
+        ++ [ nixLibs.nix-fetchers-c ];
+      nci.crates.nix-bindings-fetchers.drvConfig.mkDerivation.buildInputs =
+        config.nci.crates.nix-bindings-fetchers-sys.drvConfig.mkDerivation.buildInputs;
+      nci.crates.nix-bindings-flake-sys.drvConfig.mkDerivation.buildInputs =
+        config.nci.crates.nix-bindings-fetchers-sys.drvConfig.mkDerivation.buildInputs
+        ++ [ nixLibs.nix-flake-c ];
+      nci.crates.nix-bindings-flake.drvConfig.mkDerivation.buildInputs =
+        config.nci.crates.nix-bindings-flake-sys.drvConfig.mkDerivation.buildInputs;
     };
 }
diff --git a/nix-bindings-bdwgc-sys/Cargo.toml b/nix-bindings-bdwgc-sys/Cargo.toml
@@ -0,0 +1,15 @@
+[package]
+name = "nix-bindings-bdwgc-sys"
+version = "0.1.0"
+edition = "2021"
+build = "build.rs"
+license = "LGPL-2.1"
+
+[lib]
+path = "src/lib.rs"
+
+[dependencies]
+
+[build-dependencies]
+bindgen = "0.69"
+pkg-config = "0.3"
diff --git a/nix-bindings-bdwgc-sys/README.md b/nix-bindings-bdwgc-sys/README.md
@@ -0,0 +1,4 @@
+# nix-bindings-bdwgc-sys
+
+This crate contains generated bindings for the Boehm-Demers-Weiser garbage collector (`bdw-gc`).
+**You should not have to use this crate directly,** and so you should probably not add it to your dependencies.
diff --git a/nix-bindings-bdwgc-sys/build.rs b/nix-bindings-bdwgc-sys/build.rs
@@ -0,0 +1,27 @@
+use std::env;
+use std::path::PathBuf;
+
+fn main() {
+    println!("cargo:rerun-if-changed=include/bdwgc.h");
+
+    let mut args = Vec::new();
+    for path in pkg_config::probe_library("bdw-gc")
+        .unwrap()
+        .include_paths
+        .iter()
+    {
+        args.push(format!("-I{}", path.to_str().unwrap()));
+    }
+
+    let bindings = bindgen::Builder::default()
+        .header("include/bdwgc.h")
+        .clang_args(args)
+        .parse_callbacks(Box::new(bindgen::CargoCallbacks::new()))
+        .generate()
+        .expect("Unable to generate bindings");
+
+    let out_path = PathBuf::from(env::var("OUT_DIR").unwrap());
+    bindings
+        .write_to_file(out_path.join("bindings.rs"))
+        .expect("Couldn't write bindings!");
+}
diff --git a/nix-bindings-bdwgc-sys/include/bdwgc.h b/nix-bindings-bdwgc-sys/include/bdwgc.h
@@ -0,0 +1,2 @@
+#define GC_THREADS
+#include <gc/gc.h>
diff --git a/nix-bindings-bdwgc-sys/src/lib.rs b/nix-bindings-bdwgc-sys/src/lib.rs
@@ -0,0 +1,7 @@
+#![allow(non_upper_case_globals)]
+#![allow(non_camel_case_types)]
+#![allow(non_snake_case)]
+#![allow(dead_code)]
+#![allow(clippy::all)]
+
+include!(concat!(env!("OUT_DIR"), "/bindings.rs"));
diff --git a/nix-bindings-bindgen-raw/README.md b/nix-bindings-bindgen-raw/README.md