[Fix #9946] Avoid slow regexp match in Style/CommentedKeyword

The regular expression we use for finding the keyword on the commented
line is very slow if the comment is long. We need to reverse the order
of the two conditions so we only do the regexp matching after we've
discovered that the line begins with one of the keywords we want to
check.

changelog/fix_avoid_slow_regexp_matches_in.md

@@ -0,0 +1 @@
+* [#9946](https://github.com/rubocop/rubocop/issues/9946): Avoid slow regexp matches in `Style/CommentedKeyword`. ([@jonas054][])

lib/rubocop/cop/style/commented_keyword.rb

@@ -50,7 +50,7 @@ class CommentedKeyword < Base
 
         def on_new_investigation
           processed_source.comments.each do |comment|
-            next unless (match = line(comment).match(/(?<keyword>\S+).*#/)) && offensive?(comment)
+            next unless offensive?(comment) && (match = line(comment).match(/(?<keyword>\S+).*#/))
 
             register_offense(comment, match[:keyword])
           end

spec/rubocop/cop/style/commented_keyword_spec.rb

@@ -218,4 +218,12 @@ def x(y: "#value")
       foo = beginning_statement # comment
     RUBY
   end
+
+  it 'checks a long comment in less than one second' do
+    Timeout.timeout(1) { expect_no_offenses(<<~RUBY) }
+      begin
+        # 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
+      end
+    RUBY
+  end
 end