Merge pull request #339 from nix-community/feat/flake-parts

feat: add a flake-parts module

examples/_d2n-flake-parts/flake.nix

@@ -0,0 +1,29 @@
+{
+  inputs = {
+    dream2nix.url = "github:nix-community/dream2nix";
+    nixpkgs.follows = "dream2nix/nixpkgs";
+    flake-parts.url = "github:hercules-ci/flake-parts";
+    src.url = "github:BurntSushi/ripgrep/13.0.0";
+    src.flake = false;
+  };
+
+  outputs = {
+    self,
+    dream2nix,
+    flake-parts,
+    src,
+    ...
+  }:
+    flake-parts.lib.mkFlake {inherit self;} {
+      systems = ["x86_64-linux"];
+      imports = [dream2nix.flakeModuleBeta];
+      dream2nix = {
+        config.projectRoot = ./.;
+        # define an input for dream2nix to generate outputs for
+        inputs."ripgrep" = {
+          source = src;
+          settings = [{builder = "crane";}];
+        };
+      };
+    };
+}

flake.nix

@@ -194,6 +194,11 @@
     # kept for compat
     lib2 = d2n-lib;
 
+    flakeModuleBeta = {
+      imports = [./src/modules/flake-parts];
+      dream2nix.lib = d2n-lib;
+    };
+
     # all apps including cli, install, etc.
     apps = forAllSystems (
       system: pkgs:

src/lib/default.nix

@@ -30,6 +30,7 @@
       traceJ
       warnIfIfd
       parseSpdxId
+      isNotDrvAttrs
       ;
 
     inherit

src/modules/flake-parts/default.nix

@@ -0,0 +1,6 @@
+{
+  imports = [
+    ./interface.nix
+    ./implementation.nix
+  ];
+}

src/modules/flake-parts/implementation.nix

@@ -0,0 +1,49 @@
+{
+  config,
+  lib,
+  ...
+}: let
+  l = lib // builtins;
+  d2n = config.dream2nix;
+  makeArgs = p:
+    {
+      inherit (config) systems;
+      inherit (d2n) config;
+    }
+    // p;
+  outputs = d2n.lib.dlib.mergeFlakes (
+    l.map
+    (p: d2n.lib.makeFlakeOutputs (makeArgs p))
+    (l.attrValues d2n.inputs)
+  );
+in {
+  config = {
+    flake =
+      # make attrs default, so that users can override them without
+      # needing to use lib.mkOverride (usually, lib.mkForce)
+      l.mapAttrsRecursiveCond
+      d2n.lib.dlib.isNotDrvAttrs
+      (_: l.mkDefault)
+      outputs;
+    dream2nix.outputs = outputs;
+    perSystem = {
+      config,
+      system,
+      ...
+    }: let
+      # get output attrs that have systems
+      systemizedOutputs =
+        l.mapAttrs
+        (_: attrs: attrs.${system})
+        (
+          l.filterAttrs
+          (_: attrs: l.isAttrs attrs && l.hasAttr system attrs)
+          outputs
+        );
+    in {
+      config = {
+        dream2nix.outputs = systemizedOutputs;
+      };
+    };
+  };
+}

src/modules/flake-parts/interface.nix

@@ -0,0 +1,66 @@
+{
+  lib,
+  flake-parts-lib,
+  ...
+}: let
+  l = lib // builtins;
+  t = l.types;
+in {
+  options = {
+    dream2nix = {
+      lib = l.mkOption {
+        type = t.raw;
+        readOnly = true;
+        description = ''
+          The system-less dream2nix library.
+          This should be the the `lib` attribute of the dream2nix flake.
+        '';
+      };
+      config = l.mkOption {
+        type = t.submoduleWith {
+          modules = [../config];
+        };
+        default = {};
+        description = ''
+          The dream2nix config. This will be applied to all defined `sources`.
+          You can override this per `source` by specifying `config` for that source:
+          ```nix
+            sources."name" = {
+              config.projectSource = ./source;
+            };
+          ```
+        '';
+      };
+      inputs = l.mkOption {
+        type = t.attrsOf t.attrs;
+        default = {};
+        description = ''
+          A list of inputs to generate outputs from.
+          Each one takes the same arguments `makeFlakeOutputs` takes.
+        '';
+      };
+      outputs = l.mkOption {
+        type = t.attrsOf t.raw;
+        readOnly = true;
+        description = ''
+          The raw outputs that were generated.
+        '';
+      };
+    };
+    perSystem =
+      flake-parts-lib.mkPerSystemOption
+      ({...}: {
+        options = {
+          dream2nix = {
+            outputs = l.mkOption {
+              type = t.attrsOf t.raw;
+              readOnly = true;
+              description = ''
+                The raw outputs that were generated.
+              '';
+            };
+          };
+        };
+      });
+  };
+}

src/subsystems/rust/builders/devshell.nix

@@ -15,17 +15,17 @@
   mergeShellConfig = base: other: let
     c = base.config;
     oc = other.config;
-    i = base.imports;
-    oi = other.imports;
+    i = base.imports or [];
+    oi = other.imports or [];
     hasCConfig = config: (config ? language) && (config.language ? c);
   in {
     config =
       c
       // oc
       // {
-        packages = l.unique (c.packages ++ oc.packages);
-        commands = l.unique (c.commands ++ oc.commands);
-        env = l.unique (c.env ++ oc.env);
+        packages = l.unique ((c.packages or []) ++ (oc.packages or []));
+        commands = l.unique ((c.commands or []) ++ (oc.commands or []));
+        env = l.unique ((c.env or []) ++ (oc.env or []));
         devshell =
           (c.devshell or {})
           // (oc.devshell or {})
@@ -56,6 +56,8 @@
       passthru.config = config;
       combineWith = other:
         mkShell (mergeShellConfig config other.passthru.config);
+      addConfig = otherConfig:
+        mkShell (mergeShellConfig config {config = otherConfig;});
     };
   # convenience utils for converting a nix attribute to a shell env
   # TODO: we could probably replace this with something from nixpkgs?