Unexpected results when specifying stop words as Regexps

[rob99]

FuzzyMatch.new(['AAI Limited', 'LITED'], :stop_words=>['limited']).find('AAI Limited')
=> "AAI Limited"  # good


FuzzyMatch.new(['AAI Limited', 'LITED'], :stop_words=>[/limited/i]).find('AAI Limited')
=> "LITED"  # bad

I would expect the same result in either case, given the absence of special characters in the regexp.

[rob99]

Also found:

FuzzyMatch.new(['AAI Limited', 'LITED'], :stop_words=>[/limited/]).find('AAI Limited')
=> "AAI Limited"

So the case insensitive modifier seems to be having an undesirable impact...

[rlue]

TL;DR: This was fixed as of 4f914f2 (7/20/2015), but appears not to have been updated on rubygems. To use the most recent version, try the following line in your Gemfile:

gem 'fuzzy_match', :git => 'https://github.com/seamusabshere/fuzzy_match.git'

---

To be clear, the issue is not with the /i Regexp flag. Rather, [/limited/i] is the only version of the stop word that works! You can try it yourself:

pry(main)> FuzzyMatch.new(['AAI Limited', 'LITED']), stop_words: [/limited/i])
=> #<FuzzyMatch:0x007fd394393388
 ... @haystack=[w("AAI"), w("LITED")], ... >

vs

pry(main)> FuzzyMatch.new(['AAI Limited', 'LITED']), stop_words: [/limited/])
=> #<FuzzyMatch:0x007fd394393388
 ... @haystack=[w("AAI Limited"), w("LITED")], ... >

The problem is that the when you try to #find('AAI Limited'), the old version (the one on rubygems) only filters the stop word out of the ‘haystack’, and not out of the ‘needle’. Thus, applying the stop word makes it search for ‘AAI Limited’ in ‘AAI’ / ‘LITED’, when it should be search for just ‘AAI’.