Monkey patch active record relation query attribute hash method to better compare objects

This a important since arel and AR commonly use array - operator

Author: JesseChavez

lib/arjdbc/abstract/relation_query_attribute_monkey_patch.rb

@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+require "active_model/attribute"
+
+module ActiveRecord
+  # NOTE: improved implementation for hash methods that is used to
+  # compare objects. AR and arel commonly use `[a, b] - [b]` operations and
+  # JRuby internally uses the hash method to implement that operation,
+  # on the other hand, CRuby does not use the hash method
+  # for small arrays (length <= 16).
+  class Relation
+    # monkey patch
+    module RelationQueryAttributeMonkeyPatch
+      def hash
+        # [self.class, name, value_for_database, type].hash
+        [self.class, name, value_before_type_cast, type].hash
+      end
+    end
+
+    class QueryAttribute
+      prepend RelationQueryAttributeMonkeyPatch
+    end
+  end
+end

lib/arjdbc/mysql/adapter.rb

@@ -11,6 +11,8 @@
 require 'arjdbc/abstract/statement_cache'
 require 'arjdbc/abstract/transaction_support'
 
+require "arjdbc/abstract/relation_query_attribute_monkey_patch"
+
 module ActiveRecord
   module ConnectionAdapters
     AbstractMysqlAdapter.class_eval do

lib/arjdbc/postgresql/adapter.rb

@@ -27,6 +27,8 @@
 
 require 'active_model'
 
+require "arjdbc/abstract/relation_query_attribute_monkey_patch"
+
 module ArJdbc
   # Strives to provide Rails built-in PostgreSQL adapter (API) compatibility.
   module PostgreSQL

lib/arjdbc/sqlite3/adapter.rb

@@ -18,6 +18,8 @@
 require "active_support/core_ext/class/attribute"
 require "arjdbc/sqlite3/column"
 
+require "arjdbc/abstract/relation_query_attribute_monkey_patch"
+
 module SQLite3
   module Constants
     module Open