style: forbid one line nested license expressions

Library/Homebrew/rubocops/lines.rb

@@ -272,6 +272,20 @@ module RuboCop
         end
       end
 
+      class Licenses < FormulaCop
+        def audit_formula(_node, _class_node, _parent_class_node, body_node)
+          license_node = find_node_method_by_name(body_node, :license)
+          return unless license_node
+
+          license = parameters(license_node).first
+          return unless license.hash_type?
+          return unless license.each_descendant(:hash).count.positive?
+          return if license.source.include?("\n")
+
+          problem "Split nested license declarations onto multiple lines"
+        end
+      end
+
       class Miscellaneous < FormulaCop
         def audit_formula(_node, _class_node, _parent_class_node, body_node)
           # FileUtils is included in Formula

Library/Homebrew/test/rubocops/lines_spec.rb

@@ -647,6 +647,66 @@ describe RuboCop::Cop::FormulaAudit::LicenseArrays do
   end
 end
 
+describe RuboCop::Cop::FormulaAudit::Licenses do
+  subject(:cop) { described_class.new }
+
+  context "When auditing licenses" do
+    it "allow license strings" do
+      expect_no_offenses(<<~RUBY)
+        class Foo < Formula
+          desc "foo"
+          url 'https://brew.sh/foo-1.0.tgz'
+          license "MIT"
+        end
+      RUBY
+    end
+
+    it "allow license symbols" do
+      expect_no_offenses(<<~RUBY)
+        class Foo < Formula
+          desc "foo"
+          url 'https://brew.sh/foo-1.0.tgz'
+          license :public_domain
+        end
+      RUBY
+    end
+
+    it "allow license hashes" do
+      expect_no_offenses(<<~RUBY)
+        class Foo < Formula
+          desc "foo"
+          url 'https://brew.sh/foo-1.0.tgz'
+          license any_of: ["MIT", "0BSD"]
+        end
+      RUBY
+    end
+
+    it "allow multiline nested license hashes" do
+      expect_no_offenses(<<~RUBY)
+        class Foo < Formula
+          desc "foo"
+          url 'https://brew.sh/foo-1.0.tgz'
+          license any_of: [
+            "MIT",
+            all_of: ["0BSD", "Zlib"],
+          ]
+        end
+      RUBY
+    end
+
+    it "require multiple lines for nested license hashes" do
+      expect_offense(<<~RUBY)
+        class Foo < Formula
+          desc "foo"
+          url 'https://brew.sh/foo-1.0.tgz'
+          license any_of: ["MIT", all_of: ["0BSD", "Zlib"]]
+          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Split nested license declarations onto multiple lines
+        end
+      RUBY
+    end
+  end
+end
+
 describe RuboCop::Cop::FormulaAudit::Miscellaneous do
   subject(:cop) { described_class.new }