gistfile1.txt

module ActiveRecordStructuralOrAddition
  def or!(other) # :nodoc:
    raise
    incompatible_values = structurally_incompatible_values_for_or(other)
    unless incompatible_values.empty?
      raise ArgumentError, "Relations passed to #or must be structurally compatible. Incompatible values: #{incompatible_values}"
    end

    self.where_clause = self.where_clause.or(other.where_clause)
    self.having_clause = having_clause.or(other.having_clause)
    self.references_values += other.references_values

    self
  end

  STRUCTURAL_OR_METHODS = ActiveRecord::Relation::VALUE_METHODS - [:extending, :where, :having, :unscope, :references]
  private def structurally_incompatible_values_for_or(other)
    ActiveRecordStructuralOrAddition::STRUCTURAL_OR_METHODS.reject do |method|
      get_value(method) == other.get_value(method)
    end
  end
end

ActiveRecord::QueryMethods.prepend(ActiveRecordStructuralOrAddition)