# frozen_string_literal: true require "active_support/core_ext/string/conversions" module ActiveRecord module Associations # Keeps track of table aliases for ActiveRecord::Associations::JoinDependency class AliasTracker # :nodoc: def self.create(connection, initial_table, joins) if joins.empty? aliases = Hash.new(0) else aliases = Hash.new { |h, k| h[k] = initial_count_for(connection, k, joins) } end aliases[initial_table] = 1 new(connection, aliases) end def self.initial_count_for(connection, name, table_joins) quoted_name = nil counts = table_joins.map do |join| if join.is_a?(Arel::Nodes::StringJoin) # quoted_name should be case ignored as some database adapters (Oracle) return quoted name in uppercase quoted_name ||= connection.quote_table_name(name) # Table names + table aliases join.left.scan( /JOIN(?:\s+\w+)?\s+(?:\S+\s+)?(?:#{quoted_name}|#{name})\sON/i ).size elsif join.is_a?(Arel::Nodes::Join) join.left.name == name ? 1 : 0 elsif join.is_a?(Hash) join[name] else raise ArgumentError, "joins list should be initialized by list of Arel::Nodes::Join" end end counts.sum end # table_joins is an array of arel joins which might conflict with the aliases we assign here def initialize(connection, aliases) @aliases = aliases @connection = connection end def aliased_table_for(table_name, aliased_name, type_caster) if aliases[table_name].zero? # If it's zero, we can have our table_name aliases[table_name] = 1 Arel::Table.new(table_name, type_caster: type_caster) else # Otherwise, we need to use an alias aliased_name = @connection.table_alias_for(aliased_name) # Update the count aliases[aliased_name] += 1 table_alias = if aliases[aliased_name] > 1 "#{truncate(aliased_name)}_#{aliases[aliased_name]}" else aliased_name end Arel::Table.new(table_name, type_caster: type_caster).alias(table_alias) end end attr_reader :aliases private def truncate(name) name.slice(0, @connection.table_alias_length - 2) end end end end