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# frozen_string_literal: true
require "active_support/core_ext/hash/except"
require "active_support/core_ext/hash/slice"
require "active_record/relation/merger"
module ActiveRecord
module SpawnMethods
def spawn # :nodoc:
already_in_scope?(klass.scope_registry) ? klass.all : clone
end
# Merges in the conditions from <tt>other</tt>, if <tt>other</tt> is an ActiveRecord::Relation.
# Returns an array representing the intersection of the resulting records with <tt>other</tt>, if <tt>other</tt> 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.
#
# For conditions that exist in both relations, those from <tt>other</tt> will take precedence.
# To find the intersection of two relations, use QueryMethods#and.
def merge(other, *rest)
if other.is_a?(Array)
records & other
elsif other
spawn.merge!(other, *rest)
else
raise ArgumentError, "invalid argument: #{other.inspect}."
end
end
def merge!(other, *rest) # :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)
result = spawn
result.instance_variable_set(:@values, values)
result
end
end
end
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