feat: dev-registry for dev environments

features/dev-registry.nix

@@ -0,0 +1,16 @@
+{
+  nixos =
+    { inputs, ... }:
+    {
+      nix.registry.dev = {
+        from = {
+          type = "indirect";
+          id = "dev";
+        };
+        to = {
+          type = "path";
+          path = inputs.self.outPath;
+        };
+      };
+    };
+}

flake.nix

@@ -36,6 +36,7 @@
     };
 
     neovim-nightly-overlay.url = "github:nix-community/neovim-nightly-overlay";
+
   };
 
   outputs =

flake/devshell.nix

@@ -1,17 +1,107 @@
 _: {
   perSystem =
-    { pkgs, ... }:
+    { pkgs, lib, ... }:
+    let
+      # libraries needed by python native extensions
+      pythonLibraries = [
+        pkgs.stdenv.cc.cc.lib
+        pkgs.zlib
+        pkgs.openssl
+        pkgs.curl
+      ];
+
+      mkUv = python: {
+        packages = [
+          python
+          pkgs.uv
+        ];
+        libraries = pythonLibraries;
+        env = {
+          UV_PYTHON_DOWNLOADS = "never";
+          UV_PYTHON_PREFERENCE = "only-system";
+          UV_PYTHON = "${python}/bin/python";
+        };
+        shellHook = ''
+          unset PYTHONPATH
+          export UV_PROJECT_ENVIRONMENT="$HOME/.venvs/$(basename "$PWD")-$(echo "$PWD" | md5sum | cut -c1-8)"
+        '';
+      };
+
+      # composable dev environment components
+      # each is exposed as its own devShell, layered via `use dev` in .envrc
+      components = {
+        uv_10 = mkUv pkgs.python310;
+        uv_11 = mkUv pkgs.python311;
+        uv_12 = mkUv pkgs.python312;
+        uv_13 = mkUv pkgs.python313;
+        uv_14 = mkUv pkgs.python314;
+
+        pg_15 = {
+          packages = [ pkgs.postgresql_15 ];
+        };
+        pg_16 = {
+          packages = [ pkgs.postgresql_16 ];
+        };
+        pg_17 = {
+          packages = [ pkgs.postgresql_17 ];
+        };
+        pg_18 = {
+          packages = [ pkgs.postgresql_18 ];
+        };
+
+        rust = {
+          packages = [
+            pkgs.rustc
+            pkgs.cargo
+            pkgs.rust-analyzer
+            pkgs.openssl
+            pkgs.pkg-config
+          ];
+        };
+
+        cmake = {
+          packages = [
+            pkgs.cmake
+            pkgs.ninja
+          ];
+        };
+      };
+
+      mkComponentShell =
+        component:
+        let
+          c = components.${component};
+          libraries = c.libraries or [ ];
+          libPath = lib.makeLibraryPath libraries;
+        in
+        pkgs.mkShell (
+          {
+            packages = c.packages or [ ];
+            shellHook =
+              (lib.optionalString (libraries != [ ]) ''
+                export LD_LIBRARY_PATH="${libPath}''${LD_LIBRARY_PATH:+:$LD_LIBRARY_PATH}"
+              '')
+              + (c.shellHook or "");
+          }
+          // lib.optionalAttrs (c ? env) { inherit (c) env; }
+        );
+
+      componentShells = lib.mapAttrs (name: _: mkComponentShell name) components;
+    in
     {
       formatter = pkgs.nixfmt-tree;
 
-      devShells.default = pkgs.mkShell {
+      devShells = {
-        packages = [
+        default = pkgs.mkShell {
-          pkgs.pre-commit
+          packages = [
-          pkgs.statix
+            pkgs.pre-commit
-          pkgs.shellcheck
+            pkgs.statix
-          pkgs.shfmt
+            pkgs.shellcheck
-          pkgs.qemu
+            pkgs.shfmt
-        ];
+            pkgs.qemu
-      };
+          ];
+        };
+      }
+      // componentShells;
     };
 }

flake/hosts.nix

@@ -30,6 +30,7 @@ in
         "yubikey"
         "calibre"
         "steam"
+        "dev-registry"
         "neovim"
         "dev"
         "claude"
@@ -56,6 +57,7 @@ in
         "calibre"
         "steam"
         "initrd-ssh"
+        "dev-registry"
         "neovim"
         "dev"
         "claude"