nix: incremental builds with crane

flake.lock

@@ -1,5 +1,20 @@
 {
   "nodes": {
+    "crane": {
+      "locked": {
+        "lastModified": 1754269165,
+        "narHash": "sha256-0tcS8FHd4QjbCVoxN9jI+PjHgA4vc/IjkUSp+N3zy0U=",
+        "owner": "ipetkov",
+        "repo": "crane",
+        "rev": "444e81206df3f7d92780680e45858e31d2f07a08",
+        "type": "github"
+      },
+      "original": {
+        "owner": "ipetkov",
+        "repo": "crane",
+        "type": "github"
+      }
+    },
     "nixpkgs": {
       "locked": {
         "lastModified": 1754725699,
@@ -18,6 +33,7 @@
     },
     "root": {
       "inputs": {
+        "crane": "crane",
         "nixpkgs": "nixpkgs"
       }
     }

flake.nix

@@ -1,16 +1,20 @@
 {
   inputs.nixpkgs.url = "github:NixOS/nixpkgs?ref=nixos-unstable";
+  inputs.crane.url = "github:ipetkov/crane";
 
   outputs = {
     self,
     nixpkgs,
+    crane,
   }: let
     systems = ["x86_64-linux" "aarch64-linux"];
     forEachSystem = nixpkgs.lib.genAttrs systems;
     pkgsForEach = nixpkgs.legacyPackages;
   in {
     packages = forEachSystem (system: {
-      default = pkgsForEach.${system}.callPackage ./nix/package.nix {};
+      default = pkgsForEach.${system}.callPackage ./nix/package.nix {
+        craneLib = crane.mkLib pkgsForEach.${system};
+      };
     });
 
     devShells = forEachSystem (system: {

nix/package.nix

@@ -1,11 +1,12 @@
 {
   lib,
-  rustPlatform,
-}:
-rustPlatform.buildRustPackage (finalAttrs: {
+  craneLib,
+  runCommandNoCCLocal,
+}: let
+  inherit (craneLib) buildDepsOnly buildPackage mkDummySrc;
+
   pname = "stash";
   version = (builtins.fromTOML (builtins.readFile ../Cargo.toml)).package.version;
-
   src = let
     fs = lib.fileset;
     s = ../.;
@@ -19,18 +20,44 @@ rustPlatform.buildRustPackage (finalAttrs: {
       ];
     };
 
-  cargoLock.lockFile = "${finalAttrs.src}/Cargo.lock";
-  enableParallelBuilding = true;
+  # basically avoid crane rebuilding everything
+  # when the package version changes
+  replacedSrc = let
+    rgxIn = ''
+      name = "${pname}"
+      version = "${version}"
+    '';
+    rgxOut = ''
+      name = "${pname}"
+      version = "0.9.6"
+    '';
+  in
+    runCommandNoCCLocal "bakaSrc" {} ''
+      cp -r ${src} $out
+      substituteInPlace $out/Cargo.toml \
+         --replace-fail '${rgxIn}' '${rgxOut}'
+      substituteInPlace $out/Cargo.lock \
+         --replace-fail '${rgxIn}' '${rgxOut}'
+    '';
 
-  postInstall = ''
-    mkdir -p $out
-    install -Dm755 ${../vendor/stash.service} $out/share/stash.service
-  '';
-
-  meta = {
-    description = "Wayland clipboard manager with fast persistent history and multi-media support";
-    maintainers = [lib.maintainers.NotAShelf];
-    license = lib.licenses.mpl20;
-    mainProgram = "stash";
+  cargoArtifacts = buildDepsOnly {
+    name = "${pname}-deps";
+    strictDeps = true;
+    dummySrc = mkDummySrc {src = replacedSrc;};
   };
-})
+in
+  buildPackage {
+    inherit cargoArtifacts pname src version;
+    strictDeps = true;
+    postInstall = ''
+      mkdir -p $out
+      install -Dm755 ${../vendor/stash.service} $out/share/stash.service
+    '';
+
+    meta = {
+      description = "Wayland clipboard manager with fast persistent history and multi-media support";
+      maintainers = [lib.maintainers.NotAShelf];
+      license = lib.licenses.mpl20;
+      mainProgram = "stash";
+    };
+  }