Support flake attr nixosModule (#401)

* flake_info.nix: remove helper fn `default`

Nix has builtin syntax for fetching attrs with a default value.

* flake_info.nix: minor refactor

- Remove commented out code
- Simplify pkg filtering
- Break overlong line

* flake_info.nix: support flake attr `nixosModule`

* Support default modules in rust backend and elm

Co-authored-by: Yannik Sander <me@ysndr.de>

flake-info/src/commands/flake_info.nix

@@ -5,43 +5,32 @@ let
   nixpkgs = (import <nixpkgs> {});
   lib = nixpkgs.lib;
 
-
-  default = drv: attr: default: if drv ? ${attr} then drv.${attr} else default;
-
   # filter = lib.filterAttrs (key: _ : key == "apps" || key == "packages");
 
   withSystem = fn: lib.mapAttrs (system: drvs: (fn system drvs));
   isValid = d:
     let
-      r = builtins.tryEval (lib.isDerivation d && ! (lib.attrByPath [ "meta" "broken" ] false d) && builtins.seq d.name true && d ? outputs);
+      r = builtins.tryEval (lib.isDerivation d && ! (lib.attrByPath [ "meta" "broken" ] false d) &&
+                            builtins.seq d.name true && d ? outputs);
     in
       r.success && r.value;
-  all = pkgs:
-    let
-      validPkgs = lib.filterAttrs (k: v: isValid v) pkgs;
-    in
-      validPkgs;
-
-
+  validPkgs = lib.filterAttrs (k: v: isValid v);
 
   readPackages = system: drvs: lib.mapAttrsToList (
     attribute_name: drv: (
-      # if isValid drv then
       {
         attribute_name = attribute_name;
         system = system;
         name = drv.name;
         # TODO consider using `builtins.parseDrvName`
-        version = default drv "version" "";
+        version = drv.version or "";
         outputs = drv.outputs;
         # paths = builtins.listToAttrs ( map (output: {name = output; value = drv.${output};}) drv.outputs );
       }
       // lib.optionalAttrs (drv ? meta && drv.meta ? description) { inherit (drv.meta) description; }
       // lib.optionalAttrs (drv ? meta && drv.meta ? license) { inherit (drv.meta) license; }
-
-      # else {}
     )
-  ) (all drvs);
+  ) (validPkgs drvs);
   readApps = system: apps: lib.mapAttrsToList (
     attribute_name: app: (
       {
@@ -54,8 +43,7 @@ let
     )
   ) apps;
 
-  readOptions = modules: isNixOS: let
-
+  readOptions = let
     declarations = module: (
       lib.evalModules {
         modules = (if lib.isList module then module else [ module ]) ++ [
@@ -70,7 +58,7 @@ let
       }
     ).options;
 
-    cleanUpOption = module: opt:
+    cleanUpOption = extraAttrs: opt:
       let
         applyOnAttr = n: f: lib.optionalAttrs (builtins.hasAttr n opt) { ${n} = f opt.${n}; };
         mkDeclaration = decl:
@@ -96,31 +84,47 @@ let
         // applyOnAttr "example" substFunction # (_: { __type = "function"; })
         // applyOnAttr "type" substFunction
         // applyOnAttr "declarations" (map mkDeclaration)
-        // lib.optionalAttrs (!isNixOS) { flake = [ flake module ]; };
-
-
-    options = lib.mapAttrs (
-      attr: module: let
-        list = lib.optionAttrSetToDocList (declarations module);
+        // extraAttrs;
   in
-        map (cleanUpOption attr) (lib.filter (x: !x.internal) list)
-    ) modules;
+    { module, modulePath ? null }: let
+      opts = lib.optionAttrSetToDocList (declarations module);
+      extraAttrs = lib.optionalAttrs (modulePath != null) {
+        flake = modulePath;
+      };
     in
-    lib.flatten (builtins.attrValues options);
+      map (cleanUpOption extraAttrs) (lib.filter (x: !x.internal) opts);
 
+  readFlakeOptions = let
+    nixosModulesOpts = builtins.concatLists (lib.mapAttrsToList (moduleName: module:
+      readOptions {
+        inherit module;
+        modulePath = [ flake moduleName ];
+      }
+    ) (resolved.nixosModules or {}));
+
+    nixosModuleOpts = lib.optionals (resolved ? nixosModule) (
+      readOptions {
+        module = resolved.nixosModule;
+        modulePath = [ flake ];
+      }
+    );
+  in
+    # We assume that `nixosModules` includes `nixosModule` when there
+    # are multiple modules
+    if nixosModulesOpts != [] then nixosModulesOpts else nixosModuleOpts;
 
   read = reader: set: lib.flatten (lib.attrValues (withSystem reader set));
 
-  legacyPackages' = read readPackages (default resolved "legacyPackages" {});
-  packages' = read readPackages (default resolved "packages" {});
+  legacyPackages' = read readPackages (resolved.legacyPackages or {});
+  packages' = read readPackages (resolved.packages or {});
 
-  apps' = read readApps (default resolved "apps" {});
+  apps' = read readApps (resolved.apps or {});
 
 
   collectSystems = lib.lists.foldr (
     drv@{ attribute_name, system, ... }: set:
       let
-        present = default set "${attribute_name}" ({ platforms = []; } // drv);
+        present = set."${attribute_name}" or ({ platforms = []; } // drv);
 
         drv' = present // {
           platforms = present.platforms ++ [ system ];
@@ -138,11 +142,9 @@ rec {
   legacyPackages = lib.attrValues (collectSystems legacyPackages');
   packages = lib.attrValues (collectSystems packages');
   apps = lib.attrValues (collectSystems apps');
-  options = readOptions (default resolved "nixosModules" {}) false;
-  nixos-options = readOptions (
-    {
-      "nixos" = import "${builtins.fetchTarball { url = flake; }}/nixos/modules/module-list.nix";
-    }
-  ) true;
+  options = readFlakeOptions;
+  nixos-options = readOptions {
+    module = import "${builtins.fetchTarball { url = flake; }}/nixos/modules/module-list.nix";
+  };
   all = packages ++ apps ++ options;
 }

flake-info/src/data/export.rs

@@ -3,7 +3,7 @@
 /// Flakes, or Nixpkgs.
 use std::{convert::TryInto, path::PathBuf};
 
-use super::{import::DocValue, pandoc::PandocExt};
+use super::{import::{DocValue, ModulePath}, pandoc::PandocExt};
 use crate::data::import::NixOption;
 use log::error;
 use serde::{Deserialize, Serialize};
@@ -110,7 +110,7 @@ pub enum Derivation {
 
         option_example: Option<DocValue>,
 
-        option_flake: Option<(String, String)>,
+        option_flake: Option<ModulePath>,
     },
 }
 

flake-info/src/data/import.rs

@@ -63,8 +63,18 @@ pub struct NixOption {
     pub default: Option<DocValue>,
     pub example: Option<DocValue>,
 
-    /// If defined in a flake, contains defining flake and module
-    pub flake: Option<(String, String)>,
+    /// If defined in a flake, contains defining flake and optionally a module
+    pub flake: Option<ModulePath>,
+}
+
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+#[serde(untagged)]
+pub enum ModulePath {
+    /// A module taken from <flake>.nixosModule
+    /// JSON representation is a list, therefore use a 1-Tuple as representation
+    DefaultModule((String,)),
+    /// A module taken from <flake>.nixosModules.<name>
+    NamedModule((String, String)),
 }
 
 #[derive(Debug, Clone, PartialEq, Deserialize)]
@@ -345,6 +355,32 @@ mod tests {
             .collect();
     }
 
+    #[test]
+    fn test_flake_option() {
+        let json = r#"
+        {
+            "declarations": [],
+            "name": "test-option",
+            "flake": ["flake", "module"]
+        }
+        "#;
+
+        serde_json::from_str::<NixOption>(json).unwrap();
+    }
+
+    #[test]
+    fn test_flake_option_default_module() {
+        let json = r#"
+        {
+            "declarations": [],
+            "name": "test-option",
+            "flake": ["flake"]
+        }
+        "#;
+
+        serde_json::from_str::<NixOption>(json).unwrap();
+    }
+
     #[test]
     fn test_option_parsing() {}
 }

src/Page/Options.elm

@@ -68,7 +68,7 @@ type alias ResultItemSource =
     , source : Maybe String
 
     -- flake
-    , flake : Maybe ( String, String )
+    , flake : Maybe (List String)
     , flakeName : Maybe String
     , flakeDescription : Maybe String
     , flakeUrl : Maybe String
@@ -274,17 +274,20 @@ viewResultItem channel _ show item =
             Maybe.map asGithubLink item.source.source
 
         flakeOrNixpkgs =
-            case ( item.source.flakeName, item.source.flake, item.source.flakeUrl ) of
+            let
+                mkLink flake url =
+                    a [ href url ] [ text flake ]
+            in
+            case ( item.source.flake, item.source.flakeUrl ) of
                 -- its a flake
-                ( Just name, Just ( flake, attr ), Just flakeUrl_ ) ->
+                ( Just (flake :: []), Just url ) ->
                     Just
-                        [ li []
-                            [ a [ href flakeUrl_ ] [ text flake ]
-                            , text "#"
-                            , text attr
-                            ]
+                        [ li [] [ mkLink flake url ]
                         ]
 
+                ( Just (flake :: moduleName :: []), Just url ) ->
+                    Just [ li [] [ mkLink flake url, text "#", text moduleName ] ]
+
                 _ ->
                     Nothing
     in
@@ -344,12 +347,16 @@ findSource channel source =
         flakeOrNixpkgs =
             case ( source.flake, source.flakeUrl ) of
                 -- its a flake
-                ( Just ( name, module_ ), Just flakeUrl_ ) ->
+                ( Just (name :: attrs), Just flakeUrl_ ) ->
+                    let
+                        module_ =
+                            Maybe.withDefault "(default)" <| Maybe.map (\m -> "(Module: " ++ m ++ ")") <| List.head attrs
+                    in
                     Just <|
                         List.append
                             (Maybe.withDefault [] <| Maybe.map (\sourceFile_ -> [ sourceFile_, span [] [ text " in " ] ]) sourceFile)
                             [ span [] [ text "Flake: " ]
-                            , a [ href flakeUrl_ ] [ text <| name ++ "(Module: " ++ module_ ++ ")" ]
+                            , a [ href flakeUrl_ ] [ text <| name ++ module_ ]
                             ]
 
                 ( Nothing, _ ) ->
@@ -420,7 +427,7 @@ decodeResultItemSource =
         |> Json.Decode.Pipeline.optional "option_example" (Json.Decode.map Just Json.Decode.string) Nothing
         |> Json.Decode.Pipeline.optional "option_source" (Json.Decode.map Just Json.Decode.string) Nothing
         |> Json.Decode.Pipeline.optional "option_flake"
-            (Json.Decode.map Just <| Json.Decode.map2 Tuple.pair (Json.Decode.index 0 Json.Decode.string) (Json.Decode.index 1 Json.Decode.string))
+            (Json.Decode.map Just <| Json.Decode.list Json.Decode.string)
             Nothing
         |> Json.Decode.Pipeline.optional "flake_name" (Json.Decode.map Just Json.Decode.string) Nothing
         |> Json.Decode.Pipeline.optional "flake_description" (Json.Decode.map Just Json.Decode.string) Nothing