refactor(rust): update the way the rust.srcToolchain default works and also some defaultText

.rumdl.toml

@@ -0,0 +1,8 @@
+[global]
+disable = [
+  # line length limits
+  "MD013",
+]
+
+[MD057]
+absolute-links = "relative_to_roots"

cad/default.nix

@@ -155,8 +155,8 @@
           };
 
           # Formatter for nix files, available through 'nix fmt'
-          treefmt = lib.mkIf cfg.formatter.enable {
+          treefmt.programs = lib.mkIf cfg.formatter.enable {
-            programs.alejandra.enable = lib.mkIf cfg.formatter.nix true;
+            alejandra.enable = lib.mkIf cfg.formatter.nix true;
           };
         };
       });

flake.nix

@@ -36,6 +36,7 @@
         ./rust
         ./rust-esp32-c6
 
+        inputs.treefmt-nix.flakeModule
         flake-parts.flakeModules.flakeModules
         # define the flake.templates option
         ({lib, ...}: {
@@ -57,6 +58,13 @@
 
       systems = ["aarch64-linux" "x86_64-linux" "aarch64-darwin"];
 
-      perSystem = {pkgs, ...}: {formatter = pkgs.alejandra;};
+      perSystem = {pkgs, ...}: {
+        treefmt.programs = {
+          alejandra.enable = true; # nix
+          taplo.enable = true; # toml
+          rumdl-check.enable = true; # markdown
+          rumdl-format.enable = true; # markdown
+        };
+      };
     };
 }

rust/default.nix

@@ -29,7 +29,7 @@
         manifest = (lib.importTOML "${src}/Cargo.toml").package;
 
         craneLib =
-          if builtins.pathExists cfg.srcToolchain
+          if cfg.srcToolchain != null && builtins.pathExists cfg.srcToolchain
           then
             (inputs.crane.mkLib (pkgs.extend inputs.rust-overlay.overlays.default)).overrideToolchain (
               p: p.rust-bin.fromRustupToolchainFile cfg.srcToolchain
@@ -45,7 +45,8 @@
         # all of that work (e.g. via cachix) when running in CI
         cargoArtifacts = craneLib.buildDepsOnly ({
             inherit src buildInputs nativeBuildInputs;
-        } // cfg.cargoArtifacts.extraAttrs);
+          }
+          // cfg.cargoArtifacts.extraAttrs);
       in {
         options.krantz.rust = {
           enable = lib.mkEnableOption "building a cargo project with crane";
@@ -60,14 +61,26 @@
             description = "A path to the filtered directory of the root of the crate.";
             type = lib.types.path;
             default = craneLib.cleanCargoSource cfg.src;
-            defaultText = lib.literalExpression "config.krantz.rust.craneLib cfg.src";
+            defaultText = lib.literalExpression "config.krantz.rust.craneLib.cleanCargoSource cfg.src";
             example = lib.literalExpression "./.";
           };
           srcToolchain = lib.mkOption {
             description = "A path to the rust-toolchain(.toml) file for the repo. Will use the toolchain from nixpkgs if the file does not exist.";
-            type = lib.types.path;
+            type = lib.types.nullOr lib.types.path;
-            default = "${if cfg.src != null then cfg.src else "/dev/null"}/rust-toolchain.toml";
+            default =
-            defaultText = lib.literalExpression "cfg.src + \"/rust-toolchain.toml\"";
+              if cfg.src != null
+              then cfg.src + "/rust-toolchain.toml"
+              else null;
+            defaultText =
+              lib.literalExpression
+              /*
+              nix
+              */
+              ''
+                if cfg.src != null
+                then cfg.src + "/rust-toolchain.toml"
+                else null;
+              '';
             example = lib.literalExpression "./rust-toolchain";
           };
 
@@ -192,10 +205,10 @@
           # Your custom packages
           # Accessible through 'nix build', 'nix shell', 'nix run', etc
           packages = lib.mkIf cfg.package.enable {
-            ${cfg.package.name} =
+            ${cfg.package.name} = craneLib.buildPackage ({
-              craneLib.buildPackage ({
                 inherit src buildInputs nativeBuildInputs cargoArtifacts;
-              } // cfg.package.extraAttrs);
+              }
+              // cfg.package.extraAttrs);
           };
 
           # Formatter for nix files, available through 'nix fmt'