Add node pattern methods to handle dependency audits in a better way

Library/Homebrew/rubocops/extend/formula_cop.rb

@@ -1,4 +1,5 @@
 require "parser/current"
+require_relative "../../extend/string"
 
 module RuboCop
   module Cop
@@ -138,17 +139,14 @@ def depends_on_name_type?(node, name = nil, type = :required)
 
         case type
         when :required
-          type_match = !node.method_args.nil? &&
-                       (node.method_args.first.str_type? || node.method_args.first.sym_type?)
+          type_match = required_dependency?(node)
           if type_match && !name_match
-            name_match = node_equals?(node.method_args.first, name)
+            name_match = required_dependency_name?(node, name)
           end
         when :build, :optional, :recommended, :run
-          type_match = !node.method_args.nil? &&
-                       node.method_args.first.hash_type? &&
-                       node.method_args.first.values.first.children.first == type
+          type_match = dependency_type_hash_match?(node, type)
           if type_match && !name_match
-            name_match = node_equals?(node.method_args.first.keys.first.children.first, name)
+            name_match = dependency_name_hash_match?(node, name)
           end
         else
           type_match = false
@@ -161,6 +159,22 @@ def depends_on_name_type?(node, name = nil, type = :required)
         type_match && name_match
       end
 
+      def_node_search :required_dependency?, <<-EOS.undent
+        (send nil :depends_on ({str sym} _))
+      EOS
+
+      def_node_search :required_dependency_name?, <<-EOS.undent
+        (send nil :depends_on ({str sym} %1))
+      EOS
+
+      def_node_search :dependency_type_hash_match?, <<-EOS.undent
+        (hash (pair ({str sym} _) ({str sym} %1)))
+      EOS
+
+      def_node_search :dependency_name_hash_match?, <<-EOS.undent
+        (hash (pair ({str sym} %1) ({str sym} _)))
+      EOS
+
       # To compare node with appropriate Ruby variable
       def node_equals?(node, var)
         node == Parser::CurrentRuby.parse(var.inspect)

Library/Homebrew/test/rubocops/text_cop_spec.rb

@@ -7,6 +7,54 @@
   subject(:cop) { described_class.new }
 
   context "When auditing formula text" do
+    it "with both openssl and libressl optional dependencies" do
+      source = <<-EOS.undent
+        class Foo < Formula
+          url "http://example.com/foo-1.0.tgz"
+          homepage "http://example.com"
+
+          depends_on "openssl"
+          depends_on "libressl" => :optional
+        end
+      EOS
+
+      expected_offenses = [{  message: "Formulae should not depend on both OpenSSL and LibreSSL (even optionally).",
+                              severity: :convention,
+                              line: 6,
+                              column: 2,
+                              source: source }]
+
+      inspect_source(cop, source)
+
+      expected_offenses.zip(cop.offenses).each do |expected, actual|
+        expect_offense(expected, actual)
+      end
+    end
+
+    it "with both openssl and libressl dependencies" do
+      source = <<-EOS.undent
+        class Foo < Formula
+          url "http://example.com/foo-1.0.tgz"
+          homepage "http://example.com"
+
+          depends_on "openssl"
+          depends_on "libressl"
+        end
+      EOS
+
+      expected_offenses = [{  message: "Formulae should not depend on both OpenSSL and LibreSSL (even optionally).",
+                              severity: :convention,
+                              line: 6,
+                              column: 2,
+                              source: source }]
+
+      inspect_source(cop, source)
+
+      expected_offenses.zip(cop.offenses).each do |expected, actual|
+        expect_offense(expected, actual)
+      end
+    end
+
     it "When xcodebuild is called without SYMROOT" do
       source = <<-EOS.undent
         class Foo < Formula