Modify fuzzy_arel_match to search for equality when a term shorter than 3 characters is provided

lib/gitlab/sql/pattern.rb

@@ -4,7 +4,7 @@ module Gitlab
       extend ActiveSupport::Concern
 
       MIN_CHARS_FOR_PARTIAL_MATCHING = 3
-      REGEX_QUOTED_WORD = /(?<=^| )"[^"]+"(?= |$)/
+      REGEX_QUOTED_WORD = /(?<=\A| )"[^"]+"(?= |\z)/
 
       class_methods do
         def to_pattern(query)
@@ -20,11 +20,18 @@ module Gitlab
         end
 
         def fuzzy_arel_match(column, query)
+          query = query.squish
+          return nil unless query.present?
+
           words = select_fuzzy_words(query)
 
-          matches = words.map { |word| arel_table[column].matches(to_pattern(word)) }
-
-          matches.reduce { |result, match| result.and(match) }
+          if words.any?
+            words.map { |word| arel_table[column].matches(to_pattern(word)) }.reduce(:and)
+          else
+            # No words of at least 3 chars, but we can search for an exact
+            # case insensitive match with the query as a whole
+            arel_table[column].matches(sanitize_sql_like(query))
+          end
         end
 
         def select_fuzzy_words(query)
@@ -32,7 +39,7 @@ module Gitlab
 
           query = quoted_words.reduce(query) { |q, quoted_word| q.sub(quoted_word, '') }
 
-          words = query.split(/\s+/)
+          words = query.split
 
           quoted_words.map! { |quoted_word| quoted_word[1..-2] }
 

spec/lib/gitlab/sql/pattern_spec.rb

@@ -151,8 +151,8 @@ describe Gitlab::SQL::Pattern do
     context 'with a word shorter than 3 chars' do
       let(:query) { 'fo' }
 
-      it 'returns nil' do
-        expect(fuzzy_arel_match).to be_nil
+      it 'returns a single equality condition' do
+        expect(fuzzy_arel_match.to_sql).to match(/title.*I?LIKE 'fo'/)
       end
     end
 
@@ -164,6 +164,22 @@ describe Gitlab::SQL::Pattern do
       end
     end
 
+    context 'with two words both shorter than 3 chars' do
+      let(:query) { 'fo ba' }
+
+      it 'returns a single ILIKE condition' do
+        expect(fuzzy_arel_match.to_sql).to match(/title.*I?LIKE 'fo ba'/)
+      end
+    end
+
+    context 'with two words, one shorter 3 chars' do
+      let(:query) { 'foo ba' }
+
+      it 'returns a single ILIKE condition using the longer word' do
+        expect(fuzzy_arel_match.to_sql).to match(/title.+I?LIKE '\%foo\%'/)
+      end
+    end
+
     context 'with a multi-word surrounded by double quote and two words' do
       let(:query) { 'foo "really bar" baz' }