Generalize heroicons special case to all fetch-only git deps

fixtures/example/deps.nix

@@ -377,6 +377,20 @@ let
         in
         drv;
 
+      daisyui = stdenv.mkDerivation {
+        name = "daisyui";
+        src = fetchFromGitHub {
+          owner = "saadeghi";
+          repo = "daisyui";
+          rev = "22ecff57f2c391b80a75617325748cf4d13fdf47";
+          hash = "sha256-I2LI9VYVxQcvoMDgDWmvNyQToS1rFm12V167YxqDs24=";
+        };
+        buildPhase = ''
+          mkdir $out
+          ln -sv $src $out/src
+        '';
+      };
+
       db_connection =
         let
           version = "2.10.2";

fixtures/example/mix.exs

@@ -23,6 +23,13 @@ defmodule Example.MixProject do
     [
       {:bandit, github: "mtrudel/bandit", ref: "1.4.2", override: true},
       {:brod, "~> 3.16"},
+      {:daisyui,
+       github: "saadeghi/daisyui",
+       tag: "v5.5.20",
+       sparse: "packages/bundle",
+       app: false,
+       compile: false,
+       depth: 1},
       {:deps_nix, path: "../..", only: [:dev]},
       {:eventstore, "~> 1.4"},
       {:ex_heroicons, "~> 3.1"},

fixtures/example/mix.lock

@@ -9,6 +9,7 @@
   "cldr_utils": {:hex, :cldr_utils, "2.29.7", "2189bc0117efe91c684558e79174b45eb43135595b7d1fe9b57f53917be195c1", [:mix], [{:castore, "~> 0.1 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: true]}, {:certifi, "~> 2.5", [hex: :certifi, repo: "hexpm", optional: true]}, {:decimal, "~> 1.9 or ~> 2.0 or ~> 3.0", [hex: :decimal, repo: "hexpm", optional: false]}], "hexpm", "4bddcd597fee34e2d2829ae9ef62bcfef8d97ae5f6b75f0c6ee37a3db31aa73a"},
   "crc32cer": {:hex, :crc32cer, "0.1.8", "c6c2275c5fb60a95f4935d414f30b50ee9cfed494081c9b36ebb02edfc2f48db", [:rebar3], [], "hexpm", "251499085482920deb6c9b7aadabf9fb4c432f96add97ab42aee4501e5b6f591"},
   "ctx": {:hex, :ctx, "0.6.0", "8ff88b70e6400c4df90142e7f130625b82086077a45364a78d208ed3ed53c7fe", [:rebar3], [], "hexpm", "a14ed2d1b67723dbebbe423b28d7615eb0bdcba6ff28f2d1f1b0a7e1d4aa5fc2"},
+  "daisyui": {:git, "https://github.com/saadeghi/daisyui.git", "22ecff57f2c391b80a75617325748cf4d13fdf47", [tag: "v5.5.20", sparse: "packages/bundle", depth: 1]},
   "db_connection": {:hex, :db_connection, "2.10.2", "ae391e803a5adff104da913c2fc1c0c14a37f8b10001dcef568796e1fb7bf95c", [:mix], [{:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "510b14482330f1af6490a2fa0efd8d4f1435d1529b165647df22ac0f2df0fa93"},
   "decimal": {:hex, :decimal, "3.1.1", "430d87b04011ce6cbd4fd205be758311a81f87d552d40904abd00f015935b1d0", [:mix], [], "hexpm", "c5f25f2ced74a0587d03e6023f595db8e924c9d3922c8c8ffd9edfc4498cf1f6"},
   "digital_token": {:hex, :digital_token, "2.0.0", "fb3c74411790994895c4a61387ab322b64a682995ef2f54a4627c92d46be5d62", [:mix], [], "hexpm", "cbd2fff52770284a8251540a4b4e529e9738c6fe052d7f3c3428eb5c817385cd"},

lib/deps_nix.ex

@@ -190,11 +190,10 @@ defmodule DepsNix do
     end
   end
 
+  # Fetch-only deps become plain source derivations, but that only works for
+  # git checkouts; anything else with `app: false, compile: false` is dropped.
   defp unwanted(dep) do
-    dep.app != :heroicons &&
-      Enum.all?([:app, :compile], fn opt ->
-        Keyword.fetch(dep.opts, opt) == {:ok, false}
-      end)
+    dep.scm != Mix.SCM.Git && Packages.fetch_only?(dep)
   end
 
   defp add_output(%Options{} = options, parsed_args) do

lib/deps_nix/derivation.ex

@@ -13,7 +13,8 @@ defmodule DepsNix.Derivation do
             DepsNix.FetchFromGitHub.t()
             | DepsNix.FetchGit.t()
             | DepsNix.FetchHex.t(),
-          beam_deps: list(atom())
+          beam_deps: list(atom()),
+          fetch_only: boolean()
         }
 
   @enforce_keys [
@@ -30,15 +31,17 @@ defmodule DepsNix.Derivation do
     :name,
     :version,
     :src,
-    :beam_deps
+    :beam_deps,
+    fetch_only: false
   ]
 
   def new(dep, opts) do
     struct!(
       __MODULE__,
       [
         name: dep.app,
-        beam_deps: Enum.map(dep.deps, & &1.app)
+        beam_deps: Enum.map(dep.deps, & &1.app),
+        fetch_only: DepsNix.Packages.fetch_only?(dep)
       ]
       |> Keyword.merge(opts)
     )
@@ -196,10 +199,12 @@ defmodule DepsNix.Derivation do
       """
     end
 
-    def to_string(%DepsNix.Derivation{name: :heroicons} = drv) do
+    # Fetch-only deps aren't BEAM packages; expose the bare checkout so
+    # consumers can symlink ${pkg}/src into deps/.
+    def to_string(%DepsNix.Derivation{fetch_only: true} = drv) do
       """
       #{drv.name} = stdenv.mkDerivation {
-        name = "heroicons";
+        name = "#{drv.name}";
         src = #{drv.src |> Kernel.to_string() |> Util.indent(from: 1)}
         buildPhase = ''
           mkdir $out

lib/deps_nix/packages.ex

@@ -28,6 +28,16 @@ defmodule DepsNix.Packages do
     Enum.filter(packages, &("#{&1.app}" in permitted_names))
   end
 
+  @doc """
+  Deps declared with `app: false, compile: false` are plain source checkouts
+  (e.g. asset repos like heroicons or daisyui) rather than BEAM packages.
+  """
+  def fetch_only?(%Mix.Dep{} = dep) do
+    Enum.all?([:app, :compile], fn opt ->
+      Keyword.fetch(dep.opts, opt) == {:ok, false}
+    end)
+  end
+
   def reject_paths(deps) do
     deps
     |> Enum.reject(fn dep ->

test/deps_nix/special_treatment_test.exs

@@ -6,7 +6,7 @@ defmodule DepsNix.SpecialTreatmentTest do
   alias DepsNix.FetchFromGitHub
   alias DepsNix.FetchHex
 
-  test "heroicons needs a nested GitHub fetch" do
+  test "fetch-only deps like heroicons or daisyui get a nested GitHub fetch" do
     # the src dir is expected by mixRelease, which symlinks deps into place
     assert %Derivation{
              builder: "buildMix",
@@ -19,7 +19,8 @@ defmodule DepsNix.SpecialTreatmentTest do
                hash: "sha256-4yRqfY8r2Ar9Fr45ikD/8jK+H3g4veEHfXa9BorLxXg="
              },
              beam_deps: [],
-             app_config_path: "foo"
+             app_config_path: "foo",
+             fetch_only: true
            }
            |> to_string() == """
            heroicons = stdenv.mkDerivation {
@@ -36,6 +37,36 @@ defmodule DepsNix.SpecialTreatmentTest do
              '';
            };
            """
+
+    assert %Derivation{
+             builder: "buildMix",
+             name: :daisyui,
+             version: nil,
+             src: %FetchFromGitHub{
+               owner: "saadeghi",
+               repo: "daisyui",
+               rev: "4dbf88f9dd80e0917b7d366b0f4e28ec33ba6b52",
+               hash: "sha256-4yRqfY8r2Ar9Fr45ikD/8jK+H3g4veEHfXa9BorLxXg="
+             },
+             beam_deps: [],
+             app_config_path: "foo",
+             fetch_only: true
+           }
+           |> to_string() == """
+           daisyui = stdenv.mkDerivation {
+             name = "daisyui";
+             src = fetchFromGitHub {
+               owner = "saadeghi";
+               repo = "daisyui";
+               rev = "4dbf88f9dd80e0917b7d366b0f4e28ec33ba6b52";
+               hash = "sha256-4yRqfY8r2Ar9Fr45ikD/8jK+H3g4veEHfXa9BorLxXg=";
+             };
+             buildPhase = ''
+               mkdir $out
+               ln -sv $src $out/src
+             '';
+           };
+           """
   end
 
   test "ex_heroicons symlinks the required heroicons into place" do

test/deps_nix_test.exs

@@ -166,17 +166,28 @@ defmodule DepsNixTest do
     assert output(%DepsNix.Options{}, &stub_converger/1) =~ "with self;\n    {\n \n    };"
   end
 
-  test "creates a special fetcher derivation for heroicons, which is included in new Phoenix apps" do
-    dep = dep(name: :heroicons, dep_opts: [app: false, compile: false]) |> pick()
-    converger = fn [env: :prod] -> [dep] end
-    nix = output(%DepsNix.Options{envs: %{"prod" => :all}}, converger)
+  property "creates fetch-only derivations for git deps marked app: false and compile: false" do
+    check all dep <-
+                dep(
+                  name: :an_asset_dep,
+                  scm: Mix.SCM.Git,
+                  dep_opts: [app: false, compile: false]
+                ) do
+      converger = fn [env: :prod] -> [dep] end
+      nix = output(%DepsNix.Options{envs: %{"prod" => :all}}, converger)
 
-    assert Regex.scan(~r(heroicons), nix) |> length() >= 1,
-           "Couldn't find special-cased heroicons fetcher in #{nix}"
+      assert nix =~ "an_asset_dep = stdenv.mkDerivation",
+             "Couldn't find fetch-only fetcher for #{dep.app} in #{nix}"
+    end
   end
 
-  property "doesn't create derivations marked both app: false and compile: false" do
-    check all dep <- dep(name: :not_a_mix_dep, dep_opts: [app: false, compile: false]) do
+  property "doesn't create derivations for non-git deps marked both app: false and compile: false" do
+    check all dep <-
+                dep(
+                  name: :not_a_mix_dep,
+                  scm: Mix.SCM.Hex,
+                  dep_opts: [app: false, compile: false]
+                ) do
       converger = fn [env: :prod] -> [dep] end
       nix = output(%DepsNix.Options{envs: %{"prod" => :all}}, converger)