Require an installable artifact when auditing casks

Signed-off-by: Patrick Linnane <patrick@linnane.io>

Library/Homebrew/cask/audit.rb

@@ -344,10 +344,19 @@ module Cask
         add_error "a #{sym} stanza is required" unless cask.public_send(sym)
       end
       add_error "at least one name stanza is required" if cask.name.empty?
-      # TODO: specific DSL knowledge should not be spread around in various files like this
-      rejected_artifacts = [:uninstall, :zap]
-      installable_artifacts = cask.artifacts.reject { |k| rejected_artifacts.include?(k) }
-      add_error "at least one activatable artifact stanza is required" if installable_artifacts.empty?
+
+      installable_artifact = if cask.on_system_blocks_exist?
+        begin
+          OnSystem::VALID_OS_ARCH_TAGS.any? do |tag|
+            cask.refresh_for_tag(tag) { cask.installable_artifact? }
+          end
+        ensure
+          cask.refresh
+        end
+      else
+        cask.installable_artifact?
+      end
+      add_error "at least one installable artifact stanza is required" unless installable_artifact
     end
 
     sig { void }

Library/Homebrew/test/cask/audit_spec.rb

@@ -170,6 +170,42 @@ RSpec.describe Cask::Audit, :cask do
           it { is_expected.to error_with(/#{stanza} stanza is required/) }
         end
       end
+
+      context "when a cask has only uninstall artifacts" do
+        let(:cask) do
+          Cask::Cask.new("uninstall-only") do
+            version :latest
+            sha256 :no_check
+            url "https://brew.sh/foo.pkg"
+            name "Uninstall Only"
+            homepage "https://brew.sh/"
+            uninstall pkgutil: "org.example.foo"
+            zap trash: "~/Library/Caches/org.example.foo"
+          end
+        end
+
+        it { is_expected.to error_with("at least one installable artifact stanza is required") }
+      end
+
+      context "when a cask has an installable artifact only on Linux" do
+        let(:cask) do
+          Homebrew::SimulateSystem.with(os: :sequoia, arch: :arm) do
+            Cask::Cask.new("linux-only-artifact") do
+              version :latest
+              sha256 :no_check
+              url "https://brew.sh/foo"
+              name "Linux Only Artifact"
+              homepage "https://brew.sh/"
+
+              on_linux do
+                binary "foo"
+              end
+            end
+          end
+        end
+
+        it { is_expected.not_to error_with("at least one installable artifact stanza is required") }
+      end
     end
 
     describe "checking homepage availability" do