Port audit_desc rules to cop

Library/Homebrew/dev-cmd/audit.rb

@@ -569,39 +569,6 @@ class FormulaAuditor
     problem "New formulae should not use `deprecated_option`."
   end
 
-  def audit_desc
-    # For now, only check the description when using `--strict`
-    return unless @strict
-
-    desc = formula.desc
-
-    unless desc && !desc.empty?
-      problem "Formula should have a desc (Description)."
-      return
-    end
-
-    # Make sure the formula name plus description is no longer than 80 characters
-    # Note full_name includes the name of the tap, while name does not
-    linelength = "#{formula.name}: #{desc}".length
-    if linelength > 80
-      problem <<-EOS.undent
-        Description is too long. \"name: desc\" should be less than 80 characters.
-        Length is calculated as #{formula.name} + desc. (currently #{linelength})
-      EOS
-    end
-
-    if desc =~ /([Cc]ommand ?line)/
-      problem "Description should use \"command-line\" instead of \"#{$1}\""
-    end
-
-    if desc =~ /^([Aa]n?)\s/
-      problem "Description shouldn't start with an indefinite article (#{$1})"
-    end
-
-    return unless desc.downcase.start_with? "#{formula.name} "
-    problem "Description shouldn't include the formula name"
-  end
-
   def audit_homepage
     homepage = formula.homepage
 
@@ -1254,7 +1221,6 @@ class FormulaAuditor
     audit_class
     audit_specs
     audit_revision_and_version_scheme
-    audit_desc
     audit_homepage
     audit_bottle_spec
     audit_github_repository

Library/Homebrew/rubocops.rb

@@ -1 +1,2 @@
 require_relative "./rubocops/bottle_block_cop"
+require_relative "./rubocops/formula_desc_cop"

Library/Homebrew/rubocops/formula_desc_cop.rb

@@ -0,0 +1,67 @@
+module RuboCop
+  module Cop
+    module Homebrew
+      class FormulaDesc < Cop
+        def on_class(node)
+          class_node, parent_class_node, body = *node
+          formula_name = class_node.const_name
+          return unless parent_class_node && parent_class_node.const_name == "Formula" && body
+          check(node, body, formula_name)
+        end
+
+        private
+
+        def check(node, body, formula_name)
+          body.each_child_node(:send) do |call_node|
+            _receiver, call_name, args = *call_node
+            next unless call_name == :desc && !args.children[0].empty?
+            description = args.children[0]
+
+            source_buffer = call_node.source_range.source_buffer
+            line_number = call_node.loc.line
+            line_begin_pos = call_node.source_range.source_buffer.line_range(call_node.loc.line).begin_pos
+            desc_begin_pos = call_node.children[2].source_range.begin_pos
+
+            linelength = "#{formula_name}: #{description}".length
+            if linelength > 80
+              column = desc_begin_pos - line_begin_pos
+              length = call_node.children[2].source_range.size
+              sourcerange = source_range(source_buffer, line_number, column, length)
+              message = <<-EOS.strip_indent
+                        Description is too long. \"name: desc\" should be less than 80 characters.
+                        Length is calculated as #{formula_name} + desc. (currently #{linelength})
+                        EOS
+              add_offense(call_node, sourcerange, message)
+            end
+
+            match_object = description.match(/([Cc]ommand ?line)/)
+            if match_object
+              column = desc_begin_pos+match_object.begin(0)-line_begin_pos+1
+              length = match_object.to_s.length
+              sourcerange = source_range(source_buffer, line_number, column, length)
+              add_offense(call_node, sourcerange, "Description should use \"command-line\" instead of \"#{match_object}\"")
+            end
+
+            match_object = description.match(/^([Aa]n?)\s/)
+            if match_object
+              column = desc_begin_pos+match_object.begin(0)-line_begin_pos+1
+              length = match_object.to_s.length
+              sourcerange = source_range(source_buffer, line_number, column, length)
+              add_offense(call_node, sourcerange, "Description shouldn't start with an indefinite article (#{match_object})")
+            end
+
+            match_object = description.match(/^#{formula_name}/i)
+            if match_object
+              column = desc_begin_pos+match_object.begin(0)-line_begin_pos+1
+              length = match_object.to_s.length
+              sourcerange = source_range(source_buffer, line_number, column, length)
+              add_offense(call_node, sourcerange, "Description shouldn't include the formula name")
+            end
+            return
+          end
+          add_offense(node, node.source_range, "Formula should have a desc (Description).")
+        end
+      end
+    end
+  end
+end

Library/Homebrew/test/dev-cmd/audit_spec.rb

@@ -344,10 +344,6 @@ describe FormulaAuditor do
         end
       EOS
 
-      fa.audit_desc
-      expect(fa.problems.shift)
-        .to eq("Description shouldn't include the formula name")
-
       fa.audit_line 'ohai "#{share}/foolibc++"', 3
       expect(fa.problems.shift)
         .to eq("Use \#{pkgshare} instead of \#{share}/foolibc++")
@@ -413,32 +409,6 @@ describe FormulaAuditor do
       .to eq(["Don't recommend setuid in the caveats, suggest sudo instead."])
   end
 
-  specify "#audit_desc" do
-    formula_descriptions = [
-      { name: "foo", desc: nil,
-        problem: "Formula should have a desc" },
-      { name: "bar", desc: "bar" * 30,
-        problem: "Description is too long" },
-      { name: "baz", desc: "Baz commandline tool",
-        problem: "Description should use \"command-line\"" },
-      { name: "qux", desc: "A tool called Qux",
-        problem: "Description shouldn't start with an indefinite article" },
-    ]
-
-    formula_descriptions.each do |formula|
-      content = <<-EOS.undent
-        class #{Formulary.class_s(formula[:name])} < Formula
-          url "http://example.com/#{formula[:name]}-1.0.tgz"
-          desc "#{formula[:desc]}"
-        end
-      EOS
-
-      fa = formula_auditor formula[:name], content, strict: true
-      fa.audit_desc
-      expect(fa.problems.first).to match(formula[:problem])
-    end
-  end
-
   describe "#audit_homepage" do
     specify "homepage URLs" do
       fa = formula_auditor "foo", <<-EOS.undent, online: true