gitlab-org--gitlab-foss/app/models/concerns/from_set_operator.rb

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# frozen_string_literal: true
module FromSetOperator
# Define a high level method to more easily work with the SQL set operations
# of UNION, INTERSECT, and EXCEPT as defined by Gitlab::SQL::Union,
# Gitlab::SQL::Intersect, and Gitlab::SQL::Except respectively.
def define_set_operator(operator)
method_name = 'from_' + operator.name.demodulize.downcase
method_name = method_name.to_sym
raise "Trying to redefine method '#{method(method_name)}'" if methods.include?(method_name)
define_method(method_name) do |*members, remove_duplicates: true, remove_order: true, alias_as: table_name|
members = flatten_ar_array(members)
operator_sql =
if members.any?
operator.new(members, remove_duplicates: remove_duplicates, remove_order: remove_order).to_sql
else
where("1=0").to_sql
end
from(Arel.sql("(#{operator_sql}) #{alias_as}"))
end
# Array#flatten with ActiveRecord::Relation items will load the ActiveRecord::Relation.
# Therefore we need to roll our own flatten method.
unless method_defined?(:flatten_ar_array) # rubocop:disable Style/GuardClause
define_method :flatten_ar_array do |ary|
arrays = ary.dup
result = []
until arrays.empty?
item = arrays.shift
if item.is_a?(Array)
arrays.concat(item.dup)
else
result.push(item)
end
end
result
end
private :flatten_ar_array
end
end
end