WIP: cyclomatic complexity: indicate full method in location

lib/cc/engine/rubocop.rb

@@ -1,5 +1,6 @@
 require "json"
 require "pathname"
+require "rubocop/cop/method_complexity_patch"
 require "rubocop"
 require "cc/engine/category_parser"
 

lib/rubocop/cop/method_complexity_patch.rb

@@ -0,0 +1,18 @@
+# Monkey patching! Here be dragons.
+module RuboCop
+  module Cop
+    module MethodComplexity
+      # RuboCop's default implementation of `add_offense` in `Cop` only gets the
+      # location of the keyword associated with the problem which, for things
+      # like complexity checkers, is just the method def line. This isn't very
+      # useful for checkers where the entire method body is relevant. Fetching
+      # this information from an `Offense` instance is difficult, since the
+      # original AST is no longer available. So it's easier to monkey-path
+      # this method on complexity checkers to send the location of the entire
+      # method to the created `Offense`.
+      def add_offense(node, loc, message = nil, severity = nil)
+        super(node, node.loc, message, severity)
+      end
+    end
+  end
+end

spec/cc/engine/rubocop_spec.rb

@@ -161,6 +161,46 @@ def method
         assert_equal location, result["location"]
       end
 
+      it "includes complete method body for cyclomatic complexity issue" do
+        create_source_file("my_script", <<-EORUBY)
+          #!/usr/bin/env ruby
+
+          def method(a,b,c,d,e,f,g)
+            r = 1
+            if a
+              if !b
+                if c
+                  if !d
+                    if e
+                      if !f
+                        (1..g).each do |n|
+                          r = (r * n) - n
+                        end
+                      end
+                    end
+                  end
+                end
+              end
+            end
+            r
+          end
+        EORUBY
+        output = run_engine
+        assert includes_check?(output, "Metrics/CyclomaticComplexity")
+
+        json = JSON.parse('[' + output.split("\u0000").join(',') + ']')
+
+        result = json.select { |i| i && i["check_name"] =~ /Metrics\/CyclomaticComplexity/ }.first
+        location = {
+          "path" => "my_script",
+          "positions" => {
+            "begin" => { "column"=>11, "line"=>3 },
+            "end" => { "column"=>14, "line"=>21 }
+          }
+        }
+        assert_equal location, result["location"]
+      end
+
       def includes_check?(output, cop_name)
         issues = output.split("\0").map { |x| JSON.parse(x) }