Merge pull request #1 from snowfallorg/dev

feat: upgrade overlays to support merging namespaces

README.md

@@ -66,7 +66,7 @@ library instance with `mkLib`.
 	description = "My Flake";
 
 	inputs = {
-		nixpkgs.url = "github:nixos/nixpkgs/release-22.05";
+		nixpkgs.url = "github:nixos/nixpkgs/nixos-22.05";
 
 		snowfall-lib = {
 			url = "github:snowfallorg/lib";
@@ -247,7 +247,7 @@ packages, overlays, and shells specified by the [Flake Structure](#flake-structu
 	description = "My Flake";
 
 	inputs = {
-		nixpkgs.url = "github:nixos/nixpkgs/release-22.05";
+		nixpkgs.url = "github:nixos/nixpkgs/nixos-22.05";
 
 		snowfall-lib = {
 			url = "github:snowfallorg/lib";
@@ -279,7 +279,7 @@ You can apply overlays and modules from your flake's inputs with the following o
 	description = "My Flake";
 
 	inputs = {
-		nixpkgs.url = "github:nixos/nixpkgs/release-22.05";
+		nixpkgs.url = "github:nixos/nixpkgs/nixos-22.05";
 
 		snowfall-lib = {
 			url = "github:snowfallorg/lib";
@@ -338,7 +338,7 @@ on `pkgs` and consumers of your flake can use the generated `<your-flake>.overla
 	description = "My Flake";
 
 	inputs = {
-		nixpkgs.url = "github:nixos/nixpkgs/release-22.05";
+		nixpkgs.url = "github:nixos/nixpkgs/nixos-22.05";
 
 		snowfall-lib = {
 			url = "github:snowfallorg/lib";
@@ -391,7 +391,7 @@ mapping the `default` package or shell to the name of the one you want.
 	description = "My Flake";
 
 	inputs = {
-		nixpkgs.url = "github:nixos/nixpkgs/release-22.05";
+		nixpkgs.url = "github:nixos/nixpkgs/nixos-22.05";
 
 		snowfall-lib = {
 			url = "github:snowfallorg/lib";
@@ -437,7 +437,7 @@ include `darwin` and/or `nixos-generators` as inputs.
 	description = "My Flake";
 
 	inputs = {
-		nixpkgs.url = "github:nixos/nixpkgs/release-22.05";
+		nixpkgs.url = "github:nixos/nixpkgs/nixos-22.05";
 
 		snowfall-lib = {
 			url = "github:snowfallorg/lib";
@@ -995,6 +995,39 @@ Result:
 { x = 2; }
 ```
 
+#### `lib.snowfall.attrs.merge-shallow-packages`
+
+Merge shallow for packages, but allow one deeper layer of attributes sets.
+
+Type: `[Attrs] -> Attrs`
+
+Usage:
+
+```nix
+merge-shallow-packages [
+	{
+		inherit (pkgs) vim;
+		namespace.first = 1;
+	}
+	{
+		inherit (unstable) vim;
+		namespace.second = 2;
+	}
+]
+```
+
+Result:
+
+```nix
+{
+	vim = {/* the vim package from the last entry */};
+	namespace = {
+		first = 1;
+		second = 2;
+	};
+}
+```
+
 ### `lib.snowfall.system`
 
 #### `lib.snowfall.system.is-darwin`
@@ -1207,7 +1240,7 @@ Result:
 
 Utilities for working with channel overlays.
 
-#### `lib.snowfall.overlay.create-overlays`
+#### `lib.snowfall.overlay.create-overlays-builder`
 
 Create a flake-utils-plus overlays builder.
 
@@ -1216,7 +1249,7 @@ Type: `Attrs -> Attrs -> [(a -> b -> c)]`
 Usage:
 
 ```nix
-create-overlays { src = ./my-overlays; overlay-package-namespace = "my-packages"; }
+create-overlays-builder { src = ./my-overlays; overlay-package-namespace = "my-packages"; extra-overlays = []; }
 ```
 
 Result:
@@ -1225,6 +1258,35 @@ Result:
 (channels: [ ... ])
 ```
 
+#### `lib.snowfall.overlay.create-overlays`
+
+Create overlays to be used for flake outputs.
+
+Type: `Attrs -> Attrs`
+
+Usage:
+
+```nix
+create-overlays {
+	src = ./my-overlays;
+	packages-src = ./my-packages;
+	overlay-package-namespace = "my-namespace";
+	extra-overlays = {
+		my-example = final: prev: {};
+	};
+}
+```
+
+Result:
+
+```nix
+{
+	default = final: prev: {};
+	my-example = final: prev: {};
+	some-overlay = final: prev: {};
+}
+```
+
 ### `lib.snowfall.template`
 
 Utilities for working with flake templates.

flake.lock

@@ -1,26 +1,5 @@
 {
   "nodes": {
-    "darwin": {
-      "inputs": {
-        "nixpkgs": [
-          "nixpkgs"
-        ]
-      },
-      "locked": {
-        "lastModified": 1661882940,
-        "narHash": "sha256-4LaVFnV22WrOA0aolqqk9dXrM8crikcrLQt29G18F7M=",
-        "owner": "lnl7",
-        "repo": "nix-darwin",
-        "rev": "80cec5115aae74accc4ccfb9f84306d7863f0632",
-        "type": "github"
-      },
-      "original": {
-        "owner": "lnl7",
-        "ref": "master",
-        "repo": "nix-darwin",
-        "type": "github"
-      }
-    },
     "flake-compat": {
       "flake": false,
       "locked": {
@@ -70,49 +49,13 @@
         "type": "github"
       }
     },
-    "nixlib": {
-      "locked": {
-        "lastModified": 1636849918,
-        "narHash": "sha256-nzUK6dPcTmNVrgTAC1EOybSMsrcx+QrVPyqRdyKLkjA=",
-        "owner": "nix-community",
-        "repo": "nixpkgs.lib",
-        "rev": "28a5b0557f14124608db68d3ee1f77e9329e9dd5",
-        "type": "github"
-      },
-      "original": {
-        "owner": "nix-community",
-        "repo": "nixpkgs.lib",
-        "type": "github"
-      }
-    },
-    "nixos-generators": {
-      "inputs": {
-        "nixlib": "nixlib",
-        "nixpkgs": [
-          "nixpkgs"
-        ]
-      },
-      "locked": {
-        "lastModified": 1660727616,
-        "narHash": "sha256-zYTIvdPMYMx/EYqXODAwIIU30RiEHqNHdgarIHuEYZc=",
-        "owner": "nix-community",
-        "repo": "nixos-generators",
-        "rev": "adccd191a0e83039d537e021f19495b7bad546a1",
-        "type": "github"
-      },
-      "original": {
-        "owner": "nix-community",
-        "repo": "nixos-generators",
-        "type": "github"
-      }
-    },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1662316000,
+        "lastModified": 1665216225,
-        "narHash": "sha256-NkJHCVi6sj1+QqqXaozSJ0K23ANmvsnDmeC/6WXo+wI=",
+        "narHash": "sha256-SUuvJXGEXhmyaGJlDlptbc9I2Wai9tUx83QYIqvipfE=",
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "50c62eeda9df340ff6b83a0e2343a447af04237c",
+        "rev": "1a9935bf90e0f4225756f99e772f06d5fea9edb6",
         "type": "github"
       },
       "original": {
@@ -124,10 +67,8 @@
     },
     "root": {
       "inputs": {
-        "darwin": "darwin",
         "flake-compat": "flake-compat",
         "flake-utils-plus": "flake-utils-plus",
-        "nixos-generators": "nixos-generators",
         "nixpkgs": "nixpkgs"
       }
     }

lib/attrs/default.nix

@@ -7,10 +7,12 @@ let
   inherit (core-inputs.nixpkgs.lib)
     assertMsg
     mapAttrsToList
+    mapAttrs
     flatten
-    fold
+    foldl
     recursiveUpdate
-    mergeAttrs;
+    mergeAttrs
+    isDerivation;
 in
 {
   attrs = {
@@ -25,12 +27,33 @@ in
     # Type: [Attrs] -> Attrs
     # Usage: merge-deep [{ x = 1; } { x = 2; }]
     #   result: { x = 2; }
-    merge-deep = fold recursiveUpdate { };
+    merge-deep = foldl recursiveUpdate { };
 
     # Merge the root of a list of attribute sets.
     # Type: [Attrs] -> Attrs
     # Usage: merge-shallow [{ x = 1; } { x = 2; }]
     #   result: { x = 2; }
-    merge-shallow = fold mergeAttrs { };
+    merge-shallow = foldl mergeAttrs { };
+
+    # Merge shallow for packages, but allow one deeper layer of attribute sets.
+    # Type: [Attrs] -> Attrs
+    # Usage: merge-shallow-packages [ { inherit (pkgs) vim; some.value = true; } { some.value = false; } ]
+    #   result: { vim = ...; some.value = false; }
+    merge-shallow-packages = items:
+      foldl
+        (result: item:
+          result // (mapAttrs
+            (name: value:
+              if isDerivation value then
+                value
+              else if builtins.isAttrs value then
+                (result.${name} or { }) // value
+              else
+                value
+            )
+            item)
+        )
+        { }
+        items;
   };
 }

lib/flake/default.nix

@@ -78,9 +78,10 @@ rec {
       modules = snowfall-lib.module.create-modules {
         overrides = (full-flake-options.modules or { });
       };
-      overlays = core-inputs.flake-utils-plus.lib.exportOverlays ({
+      overlays = snowfall-lib.overlay.create-overlays {
-        inherit (user-inputs.self) pkgs inputs;
+        overlay-package-namespace = full-flake-options.overlay-package-namespace or null;
-      });
+        extra-overlays = full-flake-options.extra-exported-overlays or { };
+      };
 
       outputs-builder = channels:
         let
@@ -107,7 +108,7 @@ rec {
         snowfall-lib.attrs.merge-deep [ user-outputs outputs ];
 
       flake-options = custom-flake-options // {
-        inherit hosts templates overlays;
+        inherit hosts templates;
         inherit (user-inputs) self;
 
         lib = snowfall-lib.internal.user-lib;
@@ -117,7 +118,7 @@ rec {
 
         channelsConfig = full-flake-options.channels-config or { };
 
-        channels.nixpkgs.overlaysBuilder = snowfall-lib.overlay.create-overlays {
+        channels.nixpkgs.overlaysBuilder = snowfall-lib.overlay.create-overlays-builder {
           overlay-package-namespace = full-flake-options.overlay-package-namespace or null;
           extra-overlays = full-flake-options.overlays or [ ];
         };
@@ -125,36 +126,14 @@ rec {
         outputsBuilder = outputs-builder;
       };
 
-      flake-outputs =
+      flake-utils-plus-outputs =
         core-inputs.flake-utils-plus.lib.mkFlake flake-options;
 
-      overlay = (final: prev:
+      flake-outputs =
-        let
+        flake-utils-plus-outputs // {
-          overlay-package-namespace = full-flake-options.overlay-package-namespace or null;
+          inherit overlays;
-          user-overlay-packages =
+          overlay = overlays.default;
-            (builtins.map (overlay: overlay final prev) (builtins.attrValues flake-outputs.overlays));
+        };
-          namespaced-user-overlay-packages =
-            foldl
-              (namespaced-user-overlay-packages: user-overlay-package:
-                namespaced-user-overlay-packages // user-overlay-package.${overlay-package-namespace}
-              )
-              { }
-              user-overlay-packages;
-          merged-user-overlay-packages =
-            if overlay-package-namespace == null then
-              snowfall-lib.attrs.merge-shallow
-                user-overlay-packages
-            else
-              {
-                ${overlay-package-namespace} =
-                  (prev.${overlay-package-namespace} or { })
-                  // namespaced-user-overlay-packages;
-              };
-        in
-        merged-user-overlay-packages
-      );
     in
-    flake-outputs // {
+    flake-outputs;
-      inherit overlay;
-    };
 }

lib/overlay/default.nix

@@ -4,9 +4,10 @@
 }:
 
 let
-  inherit (core-inputs.nixpkgs.lib) assertMsg;
+  inherit (core-inputs.nixpkgs.lib) assertMsg foldl concatStringsSep;
 
   user-overlays-root = snowfall-lib.fs.get-file "overlays";
+  user-packages-root = snowfall-lib.fs.get-file "packages";
 in
 {
   overlay = {
@@ -14,7 +15,7 @@ in
     # Type: Attrs -> Attrs -> [(a -> b -> c)]
     # Usage: create-overlays { src = ./my-overlays; overlay-package-namespace = "my-packages"; }
     #   result: (channels: [ ... ])
-    create-overlays =
+    create-overlays-builder =
       { src ? user-overlays-root
       , overlay-package-namespace ? null
       , extra-overlays ? [ ]
@@ -42,5 +43,140 @@ in
         overlays = [ user-packages-overlay ] ++ extra-overlays ++ (builtins.map create-overlay user-overlays);
       in
       overlays;
+
+    # Create exported overlays from the user flake.
+    # Adapted from flake-utils-plus:
+    # https://github.com/gytis-ivaskevicius/flake-utils-plus/blob/2bf0f91643c2e5ae38c1b26893ac2927ac9bd82a/lib/exportOverlays.nix
+    # Type: Attrs -> Attrs
+    # Usage: create-overlays { src = ./my-overlays; packages-src = ./my-packages; overlay-package-namespace = "my-namespace"; extra-overlays = {}; }
+    #   result: { default = final: prev: ...; some-overlay = final: prev: ...; }
+    create-overlays =
+      { src ? user-overlays-root
+      , packages-src ? user-packages-root
+      , overlay-package-namespace ? null
+      , extra-overlays ? { }
+      }:
+      let
+        fake-pkgs = {
+          callPackage = x: x;
+          isFakePkgs = true;
+          lib = { };
+          system = "fake-system";
+        };
+
+        user-overlays = snowfall-lib.fs.get-default-nix-files-recursive src;
+
+        channel-systems = user-inputs.self.pkgs;
+
+        user-packages-overlay = final: prev:
+          let
+            user-packages = snowfall-lib.package.create-packages {
+              pkgs = final;
+              channels = channel-systems.${prev.system};
+            };
+          in
+          if overlay-package-namespace == null then
+            user-packages
+          else
+            {
+              ${overlay-package-namespace} =
+                (prev.${overlay-package-namespace} or { })
+                // user-packages;
+            };
+
+        create-overlay = (overlays: file:
+          let
+            name = builtins.unsafeDiscardStringContext (snowfall-lib.path.get-parent-directory file);
+            overlay = final: prev:
+              let
+                channels = channel-systems.${prev.system};
+                user-overlay = import file (user-inputs // { inherit channels; });
+                packages = user-packages-overlay final prev;
+                prev-with-packages =
+                  if overlay-package-namespace == null then
+                    prev // packages
+                  else
+                    prev // {
+                      ${overlay-package-namespace} =
+                        (prev.${overlay-package-namespace} or { })
+                        // packages.${overlay-package-namespace};
+                    };
+                user-overlay-packages =
+                  user-overlay
+                    final
+                    prev-with-packages;
+                outputs =
+                  user-overlay-packages;
+              in
+              if user-overlay-packages.__dontExport or false == true then
+                outputs // { __dontExport = true; }
+              else
+                outputs;
+            fake-overlay-result = overlay fake-pkgs fake-pkgs;
+          in
+          if fake-overlay-result.__dontExport or false == true then
+            overlays
+          else
+            overlays // {
+              "nixpkgs/${name}" = overlay;
+            }
+        );
+
+        overlays =
+          foldl
+            create-overlay
+            { }
+            user-overlays;
+
+        user-packages = snowfall-lib.fs.get-default-nix-files-recursive packages-src;
+
+        create-package-overlay = package-overlays: file:
+          let
+            name = builtins.unsafeDiscardStringContext (snowfall-lib.path.get-parent-directory file);
+            overlay = final: prev:
+              let
+                channels = channel-systems.${prev.system};
+                packages = snowfall-lib.package.create-packages {
+                  channels = channel-systems.${prev.system};
+                };
+              in
+              if overlay-package-namespace == null then
+                { ${name} = packages.${name}; }
+              else
+                {
+                  ${overlay-package-namespace} =
+                    (prev.${overlay-package-namespace} or { })
+                    // { ${name} = packages.${name}; };
+                };
+          in
+          package-overlays //
+          {
+            "nixpkgs/${name}" = overlay;
+          };
+
+        package-overlays =
+          foldl
+            create-package-overlay
+            { }
+            user-packages;
+
+        default-overlay = final: prev:
+          let
+            overlays-list = builtins.attrValues overlays;
+            package-overlays-list = builtins.attrValues package-overlays;
+
+            overlays-results = builtins.map (overlay: overlay final prev) overlays-list;
+            package-overlays-results = builtins.map (overlay: overlay final prev) package-overlays-list;
+
+            merged-results = snowfall-lib.attrs.merge-shallow-packages
+              (package-overlays-results ++ overlays-results);
+          in
+          merged-results;
+      in
+      package-overlays
+      // overlays
+      // { default = default-overlay; }
+      // extra-overlays;
   };
 }
+