style: check deprecate! reason

Library/Homebrew/rubocops/deprecate.rb

@@ -32,6 +32,43 @@ module RuboCop
           (pair (sym :date) $str)
         EOS
       end
+
+      # This cop audits deprecate! reason
+      class DeprecateReason < FormulaCop
+        def audit_formula(_node, _class_node, _parent_class_node, body_node)
+          deprecate_node = find_node_method_by_name(body_node, :deprecate!)
+
+          return if deprecate_node.nil?
+
+          deprecate_reason(deprecate_node) do |reason_node|
+            offending_node(reason_node)
+            reason_string = string_content(reason_node)
+
+            problem "Do not start the reason with `it`" if reason_string.start_with?("it ")
+
+            problem "Do not end the reason with a punctuation mark" if %w[. ! ?].include?(reason_string[-1])
+
+            return
+          end
+
+          problem 'Add a reason for deprecation: `deprecate! because: "..."`'
+        end
+
+        def autocorrect(node)
+          return unless node.str_type?
+
+          lambda do |corrector|
+            reason = string_content(node)
+            reason = reason[3..] if reason.start_with?("it ")
+            reason.chop! if %w[. ! ?].include?(reason[-1])
+            corrector.replace(node.source_range, "\"#{reason}\"")
+          end
+        end
+
+        def_node_search :deprecate_reason, <<~EOS
+          (pair (sym :because) $str)
+        EOS
+      end
     end
   end
 end

Library/Homebrew/test/.rubocop_todo.yml

@@ -21,7 +21,7 @@ RSpec/InstanceVariable:
     - 'utils/git_spec.rb'
     - 'version_spec.rb'
 
-# Offense count: 75
+# Offense count: 76
 RSpec/MultipleDescribes:
   Exclude:
     - 'ENV_spec.rb'
@@ -93,6 +93,7 @@ RSpec/MultipleDescribes:
     - 'patch_spec.rb'
     - 'rubocops/checksum_spec.rb'
     - 'rubocops/class_spec.rb'
+    - 'rubocops/deprecate_spec.rb'
     - 'rubocops/formula_desc_spec.rb'
     - 'rubocops/lines_spec.rb'
     - 'rubocops/text_spec.rb'

Library/Homebrew/test/rubocops/deprecate_spec.rb

@@ -101,3 +101,145 @@ describe RuboCop::Cop::FormulaAudit::DeprecateDate do
     end
   end
 end
+
+describe RuboCop::Cop::FormulaAudit::DeprecateReason do
+  subject(:cop) { described_class.new }
+
+  context "When auditing formula for deprecate! because:" do
+    it "deprecation reason is acceptable" do
+      expect_no_offenses(<<~RUBY)
+        class Foo < Formula
+          url 'https://brew.sh/foo-1.0.tgz'
+          deprecate! because: "is broken"
+        end
+      RUBY
+    end
+
+    it "deprecation reason is acceptable with date" do
+      expect_no_offenses(<<~RUBY)
+        class Foo < Formula
+          url 'https://brew.sh/foo-1.0.tgz'
+          deprecate! date: "2020-08-28", because: "is broken"
+        end
+      RUBY
+    end
+
+    it "deprecation reason is absent" do
+      expect_offense(<<~RUBY)
+        class Foo < Formula
+          url 'https://brew.sh/foo-1.0.tgz'
+          deprecate!
+          ^^^^^^^^^^ Add a reason for deprecation: `deprecate! because: "..."`
+        end
+      RUBY
+    end
+
+    it "deprecation reason is absent with date" do
+      expect_offense(<<~RUBY)
+        class Foo < Formula
+          url 'https://brew.sh/foo-1.0.tgz'
+          deprecate! date: "2020-08-28"
+          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Add a reason for deprecation: `deprecate! because: "..."`
+        end
+      RUBY
+    end
+
+    it "deprecation reason starts with `it`" do
+      expect_offense(<<~RUBY)
+        class Foo < Formula
+          url 'https://brew.sh/foo-1.0.tgz'
+          deprecate! because: "it is broken"
+                              ^^^^^^^^^^^^^^ Do not start the reason with `it`
+        end
+      RUBY
+    end
+
+    it "deprecation reason starts with `it` with date" do
+      expect_offense(<<~RUBY)
+        class Foo < Formula
+          url 'https://brew.sh/foo-1.0.tgz'
+          deprecate! date: "2020-08-28", because: "it is broken"
+                                                  ^^^^^^^^^^^^^^ Do not start the reason with `it`
+        end
+      RUBY
+    end
+
+    it "deprecation reason ends with a period" do
+      expect_offense(<<~RUBY)
+        class Foo < Formula
+          url 'https://brew.sh/foo-1.0.tgz'
+          deprecate! because: "is broken."
+                              ^^^^^^^^^^^^ Do not end the reason with a punctuation mark
+        end
+      RUBY
+    end
+
+    it "deprecation reason ends with an exclamation point" do
+      expect_offense(<<~RUBY)
+        class Foo < Formula
+          url 'https://brew.sh/foo-1.0.tgz'
+          deprecate! because: "is broken!"
+                              ^^^^^^^^^^^^ Do not end the reason with a punctuation mark
+        end
+      RUBY
+    end
+
+    it "deprecation reason ends with a question mark" do
+      expect_offense(<<~RUBY)
+        class Foo < Formula
+          url 'https://brew.sh/foo-1.0.tgz'
+          deprecate! because: "is broken?"
+                              ^^^^^^^^^^^^ Do not end the reason with a punctuation mark
+        end
+      RUBY
+    end
+
+    it "deprecation reason ends with a period with date" do
+      expect_offense(<<~RUBY)
+        class Foo < Formula
+          url 'https://brew.sh/foo-1.0.tgz'
+          deprecate! date: "2020-08-28", because: "is broken."
+                                                  ^^^^^^^^^^^^ Do not end the reason with a punctuation mark
+        end
+      RUBY
+    end
+
+    it "auto corrects to remove `it`" do
+      source = <<~RUBY
+        class Foo < Formula
+          url 'https://brew.sh/foo-1.0.tgz'
+          deprecate! because: "it is broken"
+        end
+      RUBY
+
+      corrected_source = <<~RUBY
+        class Foo < Formula
+          url 'https://brew.sh/foo-1.0.tgz'
+          deprecate! because: "is broken"
+        end
+      RUBY
+
+      new_source = autocorrect_source(source)
+      expect(new_source).to eq(corrected_source)
+    end
+
+    it "auto corrects to remove punctuation" do
+      source = <<~RUBY
+        class Foo < Formula
+          url 'https://brew.sh/foo-1.0.tgz'
+          deprecate! because: "is broken."
+        end
+      RUBY
+
+      corrected_source = <<~RUBY
+        class Foo < Formula
+          url 'https://brew.sh/foo-1.0.tgz'
+          deprecate! because: "is broken"
+        end
+      RUBY
+
+      new_source = autocorrect_source(source)
+      expect(new_source).to eq(corrected_source)
+    end
+  end
+end