style: convert from license array to license hash

Library/Homebrew/rubocops/lines.rb

@@ -254,6 +254,24 @@ module RuboCop
         end
       end
 
+      class LicenseArrays < 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.array_type?
+
+          problem "Use `license any_of: #{license.source}` instead of `license #{license.source}`"
+        end
+
+        def autocorrect(node)
+          lambda do |corrector|
+            corrector.replace(node.source_range, "license any_of: #{parameters(node).first.source}")
+          end
+        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

@@ -579,6 +579,74 @@ describe RuboCop::Cop::FormulaAudit::ShellVariables do
   end
 end
 
+describe RuboCop::Cop::FormulaAudit::LicenseArrays 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 "require using :any_of instead of a license array" do
+      expect_offense(<<~RUBY)
+        class Foo < Formula
+          desc "foo"
+          url 'https://brew.sh/foo-1.0.tgz'
+          license ["MIT", "0BSD"]
+          ^^^^^^^^^^^^^^^^^^^^^^^ Use `license any_of: ["MIT", "0BSD"]` instead of `license ["MIT", "0BSD"]`
+        end
+      RUBY
+    end
+
+    it "corrects license arrays to hash with :any_of" do
+      source = <<~RUBY
+        class Foo < Formula
+          desc "foo"
+          url 'https://brew.sh/foo-1.0.tgz'
+          license ["MIT", "0BSD"]
+        end
+      RUBY
+
+      corrected_source = <<~RUBY
+        class Foo < Formula
+          desc "foo"
+          url 'https://brew.sh/foo-1.0.tgz'
+          license any_of: ["MIT", "0BSD"]
+        end
+      RUBY
+
+      new_source = autocorrect_source(source)
+      expect(new_source).to eq(corrected_source)
+    end
+  end
+end
+
 describe RuboCop::Cop::FormulaAudit::Miscellaneous do
   subject(:cop) { described_class.new }