Don't report same line for multiple duplications

This uses Ruby's
[`set`](http://ruby-doc.org/stdlib-2.2.3/libdoc/set/rdoc/Set.html) class
to keep track of which lines in every file is reported to prevent
reporting the same line multiple times.

This happens most frequently with JavaScript since the Babel generated
ast is verbose and can expand a single line into a large s-expression
tree which can have several duplications.

Author: BlakeWilliams

lib/cc/engine/analyzers/reporter.rb

@@ -12,6 +12,7 @@ def initialize(engine_config, language_strategy, io)
           @engine_config = engine_config
           @language_strategy = language_strategy
           @io = io
+          @reports = Set.new
         end
 
         def run
@@ -35,7 +36,12 @@ def process_files
 
         def report
           flay.report(StringIO.new).each do |issue|
-            io.puts "#{new_violation(issue).to_json}\0"
+            violation = new_violation(issue)
+
+            unless reports.include?(violation.report_name)
+              reports.add(violation.report_name)
+              io.puts "#{violation.format.to_json}\0"
+            end
           end
         end
 
@@ -46,6 +52,8 @@ def process_sexp(sexp)
 
         private
 
+        attr_reader :reports
+
         def flay
           @flay ||= Flay.new(flay_options)
         end
@@ -58,7 +66,7 @@ def mass_threshold
 
         def new_violation(issue)
           hashes = flay.hashes[issue.structural_hash]
-          Violation.new(language_strategy.base_points, issue, hashes).format
+          Violation.new(language_strategy.base_points, issue, hashes)
         end
 
         def flay_options

lib/cc/engine/analyzers/violation.rb

@@ -26,6 +26,10 @@ def format
           }
         end
 
+        def report_name
+          "#{current_sexp.file}-#{current_sexp.line}"
+        end
+
         private
 
         attr_reader :base_points, :hashes

spec/cc/engine/analyzers/javascript/main_spec.rb

@@ -58,6 +58,16 @@
       expect(run_engine(engine_conf)).to be_empty
   end
 
+  it "does not report the same line for multiple issues" do
+    create_source_file("dup.jsx", <<-EOJSX)
+          <a className='button button-primary full' href='#' onClick={this.onSubmit.bind(this)}>Login</a>
+    EOJSX
+
+    result = run_engine(engine_conf).strip
+    issues = result.split("\0")
+    expect(issues.length).to eq 1
+  end
+
   def create_source_file(path, content)
     File.write(File.join(@code, path), content)
   end