gracefully handle nokogiri errors

lib/deadweight.rb

@@ -22,6 +22,7 @@ def initialize
     @pages = []
     @rules = ""
     @ignore_selectors = []
+    @error_selectors = []
     @mechanize = false
     @log_file = STDERR
     yield self and run if block_given?
@@ -37,9 +38,14 @@ def analyze(html)
 
       next if stripped_selector.empty?
 
-      if doc.search(stripped_selector).any?
-        log.puts("  #{selector.green}")
-        selector
+      begin
+        if doc.search(stripped_selector).any?
+          log.puts("  #{selector.green}")
+          selector
+        end
+      rescue Nokogiri::CSS::SyntaxError => e
+        log.puts("  #{selector.red}")
+        @error_selectors << selector
       end
     end
   end
@@ -85,6 +91,7 @@ def reset!
   def report
     log.puts
     log.puts "found #{@unused_selectors.size} unused selectors out of #{@total_selectors} total".yellow
+    log.puts "found #{@error_selectors.size} which could not be parsed".red
     log.puts
   end
 
@@ -125,6 +132,8 @@ def run
 
   def dump(output)
     output.puts(@unused_selectors)
+    output.puts "== Error"
+    output.puts(@error_selectors)
   end
 
   def process!(html)

test/fixtures/style.css

@@ -27,4 +27,6 @@ input#fancy:nth-child(2):not(#z.o[type='file']) {
     color: red;
 }
 
-@-webkit-keyframes rainbow {}
+@-webkit-keyframes rainbow {}
+
+* :click { outline: 0; }

test/test_helper.rb

@@ -9,6 +9,7 @@
 class Test::Unit::TestCase
   UNUSED_SELECTORS = ['#foo .bar .baz']
   USED_SELECTORS   = ['#foo', '#foo .bar']
+  ERROR_SELECTORS  = ['* :click']
 
   def self.should_correctly_report_selectors
     should "report unused selectors" do
@@ -18,6 +19,10 @@ def self.should_correctly_report_selectors
     should "not report used selectors" do
       assert_does_not_report_used_selectors(@result)
     end
+
+    should "report errored selectors" do
+      assert_reports_error_selectors(@result)
+    end
   end
 
   def assert_correct_selectors_in_output(output)
@@ -32,6 +37,12 @@ def assert_reports_unused_selectors(output)
     end
   end
 
+  def assert_reports_error_selectors(output)
+    ERROR_SELECTORS.each do |s|
+      assert output.include?(s), "output is missing #{s.inspect}:\n#{output}"
+    end
+  end
+
   def assert_does_not_report_used_selectors(output)
     USED_SELECTORS.each do |s|
       assert !output.include?(s), "output should not contain #{s.inspect}:\n#{output}"