feat: allow options for deps

examples/no-flake/derivation/default.nix

@@ -14,4 +14,4 @@
     system = builtins.currentSystem;
   };
 in
-  drv-parts.lib.derivationFromModules hello
+  drv-parts.lib.derivationFromModules {} hello

examples/no-flake/hello-from-nixpkgs/default.nix

@@ -25,7 +25,7 @@
     stdenv = pkgs.stdenv;
   };
 
-  hello = drv-parts.lib.derivationFromModules [
+  hello = drv-parts.lib.derivationFromModules {} [
     helloDefaultNix
     helloDeps
   ];

examples/no-flake/mkDerivation/default.nix

@@ -22,4 +22,4 @@
     };
   };
 in
-  drv-parts.lib.derivationFromModules hello
+  drv-parts.lib.derivationFromModules {} hello

lib.nix

@@ -4,9 +4,10 @@
 let
   l = lib // builtins;
 
-  derivationFromModules = modules: let
+  derivationFromModules = dependencySets: modules: let
     drv = lib.evalModules {
       modules = if l.isList modules then modules else [modules];
+      specialArgs = {inherit dependencySets;};
     };
   in
     drv.config.final.derivation;

lib/makeModule.nix

@@ -32,45 +32,27 @@ defaultNix: let
   # generated nixos options for all flags
   flagOptions = makeFlagOptions flagArgs;
 
-  # throws error listing missing deps.xxx entries
-  throwMissingDepsError = missingDepNames: throw ''
-    You are trying to generate a module from a legacy default.nix file
-      located under ${defaultNix},
-      but the `deps` option is not populated with all required dependencies.
-    The following dependencies are missing:
-      - ${l.concatStringsSep "\n  - " missingDepNames}
-  '';
-
-  # Ensure that all required default.nix dependencies are passed via `deps`.
-  # This is a bit hacky. It would be nicer if we could define `deps.{foo}`
-  #   as an individual option, but `deps` is already defined as `coercedTo`
-  #   which does not support nested options.
-  ensureDepsPopulated = deps: let
-    missingDeps = l.filterAttrs (depName: _: ! deps ? ${depName}) depArgs;
-    missingDepNames = l.attrNames missingDeps;
-  in
-    if missingDeps == {}
-    then deps
-    else throwMissingDepsError missingDepNames;
-
   # override func that exposes mkDerivation arguments
   passthruMkDrvArgs = oldArgs: {passthru.__mkDrvArgs = oldArgs;};
 
   getMkDrvArgs = drv: (drv.overrideAttrs passthruMkDrvArgs).__mkDrvArgs;
 
+  mkDepOpt = depName: _: l.mkOption {
+    description = "Specify a package for the dependency ${depName}.";
+    type = t.raw;
+  };
+
 in {config, options, ...}: {
 
   imports = [../modules/mkDerivation/interface.nix];
 
   options.flags = flagOptions;
+  options.deps = l.mapAttrs mkDepOpt depArgs;
 
   config = let
 
-    # raises errors if a dependency is missing from `config.deps`
-    ensuredDeps = ensureDepsPopulated config.deps;
-
     pickFlag = flagName: _: config.flags.${flagName};
-    pickDep = depName: _: ensuredDeps.${depName};
+    pickDep = depName: _: config.deps.${depName};
     flagArgs' = l.mapAttrs pickFlag flagArgs;
     depArgs' = l.mapAttrs pickDep depArgs;
 
@@ -123,12 +105,24 @@ in {config, options, ...}: {
       config.stdenv = config.stdenv;
     };
 
-    finalDerivation = drvPartsLib.derivationFromModules [finalDrvModule];
+    finalDerivation = drvPartsLib.derivationFromModules {} [finalDrvModule];
+
+    /*
+      Populate deps with some defaults.
+      `lib` should be taken from the current module.
+      `stdenv` should be taken from `config.stdenv`.
+    */
+    deps' = {
+      inherit lib;
+      inherit (config) stdenv;
+    };
+    deps'' = l.intersectAttrs depArgs deps';
+    deps = l.mapAttrs (_: dep: l.mkDefault dep) deps'';
 
   in
 
   {
-    deps.lib = lib;
+    deps = deps;
     final.derivation = finalDerivation;
   };
 }

modules/derivation-common/interface.nix

@@ -1,7 +1,6 @@
 {config, lib, dependencySets, ...}: let
   l = lib // builtins;
   t = l.types;
-  callDeps = func: func dependencySets;
   optNullOrBool = l.mkOption {
     type = t.nullOr t.bool;
     default = null;
@@ -116,12 +115,12 @@
 
         So deps should be specific, but not overly specific. For instance, the caller shouldn't have to know the version of a dependency in order to override it. The name should suffice. (e.g. `nix = nixVersions.nix_2_12` instead of `inherit (nixVersions) nix_2_12`.
       '';
-      type =
-        t.coercedTo
-        (t.functionTo (t.lazyAttrsOf t.raw))
-        callDeps
-        (t.lazyAttrsOf t.raw);
-      default = {};
+      type = t.submoduleWith {
+        # TODO: This could be made stricter by removing the freeformType
+        # Maybe add option `strictDeps = true/false` ? ;P
+        modules = [{freeformType = t.lazyAttrsOf t.raw;}];
+        specialArgs = dependencySets;
+      };
       example = lib.literalExpression ''
         {pkgs, inputs', ...}: {
           inherit (pkgs) stdenv;

modules/drv-parts.nix

@@ -13,7 +13,7 @@ in {
               modules = [./derivation-common];
               specialArgs = {
                 inherit (inputs.drv-parts) drv-backends;
-                inherit (config) dependencySets;
+                inherit (config.drv-parts) dependencySets;
               };
             }
           );
@@ -66,7 +66,7 @@ in {
           '';
         };
 
-        dependencySets = l.mkOption {
+        drv-parts.dependencySets = l.mkOption {
           type = t.lazyAttrsOf t.raw;
           default = {
             inherit pkgs inputs';