sanitize_sql_like escapes escape_character not only backslash.

* This is a follow up to: fe4b0eee05f59831e1468ed50f55fbad0ce11e1d
* The originating PR is #14222
* It should fix the build

activerecord/lib/active_record/sanitization.rb

@@ -110,7 +110,8 @@ def sanitize_sql_hash_for_assignment(attrs, table)
       # Sanitizes a +string+ so that it is safe to use within a sql
       # LIKE statement. This method uses +escape_character+ to escape all occurrences of "\", "_" and "%"
       def sanitize_sql_like(string, escape_character = "\\")
-        string.gsub(/[\\_%]/) { |x| [escape_character, x].join }
+        pattern = Regexp.union(escape_character, "%", "_")
+        string.gsub(pattern) { |x| [escape_character, x].join }
       end
 
       # Accepts an array of conditions. The array has each value

activerecord/test/cases/sanitize_test.rb

@@ -62,19 +62,20 @@ def test_sanitize_sql_like
   def test_sanitize_sql_like_with_custom_escape_character
     assert_equal '100!%', Binary.send(:sanitize_sql_like, '100%', '!')
     assert_equal 'snake!_cased!_string', Binary.send(:sanitize_sql_like, 'snake_cased_string', '!')
-    assert_equal 'C:!\\Programs!\\MsPaint', Binary.send(:sanitize_sql_like, 'C:\\Programs\\MsPaint', '!')
+    assert_equal 'great!!', Binary.send(:sanitize_sql_like, 'great!', '!')
+    assert_equal 'C:\\Programs\\MsPaint', Binary.send(:sanitize_sql_like, 'C:\\Programs\\MsPaint', '!')
     assert_equal 'normal string 42', Binary.send(:sanitize_sql_like, 'normal string 42', '!')
   end
 
   def test_sanitize_sql_like_example_use_case
     searchable_post = Class.new(Post) do
       def self.search(term)
-        where("title LIKE ?", sanitize_sql_like(term))
+        where("title LIKE ?", sanitize_sql_like(term, '!'))
       end
     end
 
-    assert_sql /LIKE '20\\% \\_reduction\\_'/ do
-      searchable_post.search("20% _reduction_").to_a
+    assert_sql /LIKE '20!% !_reduction!_!!'/ do
+      searchable_post.search("20% _reduction_!").to_a
     end
   end
 end