require 'active_support/core_ext/hash/except' require 'active_support/core_ext/hash/slice' require 'active_record/relation/merger' module ActiveRecord module SpawnMethods # This is overridden by Associations::CollectionProxy def spawn #:nodoc: clone end # Merges in the conditions from other, if other is an ActiveRecord::Relation. # Returns an array representing the intersection of the resulting records with other, if other is an array. # # Post.where(published: true).joins(:comments).merge( Comment.where(spam: false) ) # # Performs a single join query with both where conditions. # # recent_posts = Post.order('created_at DESC').first(5) # Post.where(published: true).merge(recent_posts) # # Returns the intersection of all published posts with the 5 most recently created posts. # # (This is just an example. You'd probably want to do this with a single query!) # # Procs will be evaluated by merge: # # Post.where(published: true).merge(-> { joins(:comments) }) # # => Post.where(published: true).joins(:comments) # # This is mainly intended for sharing common conditions between multiple associations. def merge(other) if other.is_a?(Array) to_a & other elsif other spawn.merge!(other) else raise ArgumentError, "invalid argument: #{other.inspect}." end end def merge!(other) # :nodoc: if other.is_a?(Hash) Relation::HashMerger.new(self, other).merge elsif other.is_a?(Relation) Relation::Merger.new(self, other).merge elsif other.respond_to?(:to_proc) instance_exec(&other) else raise ArgumentError, "#{other.inspect} is not an ActiveRecord::Relation" end end # Removes from the query the condition(s) specified in +skips+. # # Post.order('id asc').except(:order) # discards the order condition # Post.where('id > 10').order('id asc').except(:where) # discards the where condition but keeps the order def except(*skips) relation_with values.except(*skips) end # Removes any condition from the query other than the one(s) specified in +onlies+. # # Post.order('id asc').only(:where) # discards the order condition # Post.order('id asc').only(:where, :order) # uses the specified order def only(*onlies) relation_with values.slice(*onlies) end private def relation_with(values) # :nodoc: result = Relation.create(klass, table, predicate_builder, values) result.extend(*extending_values) if extending_values.any? result end end end