1 files changed, 33 insertions, 0 deletions
diff --git a/Library/Homebrew/rubocops/components_redundancy_cop.rb b/Library/Homebrew/rubocops/components_redundancy_cop.rb
new file mode 100644
index 000000000..3d95d6c05
--- /dev/null
+++ b/Library/Homebrew/rubocops/components_redundancy_cop.rb
@@ -0,0 +1,33 @@
+require_relative "./extend/formula_cop"
+
+module RuboCop
+  module Cop
+    module Homebrew
+      # This cop checks if redundant components are present and other component errors
+      #
+      # - `url|checksum|mirror` should be inside `stable` block
+      # - `head` and `head do` should not be simultaneously present
+      # - `bottle :unneeded/:disable` and `bottle do` should not be simultaneously present
+
+      class ComponentsRedundancy < FormulaCop
+        HEAD_MSG = "`head` and `head do` should not be simultaneously present".freeze
+        BOTTLE_MSG = "`bottle :modifier` and `bottle do` should not be simultaneously present".freeze
+
+        def audit_formula(_node, _class_node, _parent_class_node, formula_class_body_node)
+          stable_block = find_block(formula_class_body_node, :stable)
+          if stable_block
+            [:url, :sha256, :mirror].each do |method_name|
+              problem "`#{method_name}` should be put inside `stable` block" if method_called?(formula_class_body_node, method_name)
+            end
+          end
+
+          problem HEAD_MSG if method_called?(formula_class_body_node, :head) &&
+                              find_block(formula_class_body_node, :head)
+
+          problem BOTTLE_MSG if method_called?(formula_class_body_node, :bottle) &&
+                                find_block(formula_class_body_node, :bottle)
+        end
+      end
+    end
+  end
+end