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# frozen-string-literal: true
module Sequel
module Plugins
# The auto_restrict_eager_graph plugin will automatically disallow the use
# of eager_graph for associations that have associated blocks but no :graph_*
# association options. The reason for this is the block will have an effect
# during regular and eager loading, but not loading via eager_graph, and it
# is likely that whatever the block is doing should have an equivalent done
# when eager_graphing. Most likely, not including a :graph_* option was either
# an oversight (and one should be added), or use with eager_graph was never
# intended (and usage should be forbidden). Disallowing eager_graph in this
# case prevents likely unexpected behavior during eager_graph.
#
# As an example of this, consider the following code:
#
# Album.one_to_many :popular_tracks, class: :Track do |ds|
# ds = ds.where(popular: true)
# end
#
# Album.eager(:popular_tracks).all
# # SELECT * FROM albums
# # SELECT * FROM tracks WHERE ((popular IS TRUE) AND (album_id IN (...)))
#
# # Notice that no condition for tracks.popular is added.
# Album.eager_graph(:popular_tracks).all
# # SELECT ... FROM albums LEFT JOIN tracks ON (tracks.album_id = albums.id)
#
# With the auto_restrict_eager_graph plugin, the eager_graph call above will
# raise an error, alerting you to the fact that you either should not be
# using eager_graph with the association, or that you should be adding an
# appropriate :graph_* option, such as:
#
# Album.one_to_many :popular_tracks, class: :Track, graph_conditions: {popular: true} do |ds|
# ds = ds.where(popular: true)
# end
#
# Usage:
#
# # Automatically restrict eager_graph for associations if appropriate for all
# # model subclasses (called before loading subclasses)
# Sequel::Model.plugin :auto_restrict_eager_graph
#
# # Automatically restrict eager_graph for associations in Album class
# Album.plugin :auto_restrict_eager_graph
module AutoRestrictEagerGraph
module ClassMethods
# When defining an association, if a block is given for the association, but
# a :graph_* option is not used, disallow the use of eager_graph.
def associate(type, name, opts = OPTS, &block)
opts = super
if opts[:block] && !opts.has_key?(:allow_eager_graph) && !opts[:orig_opts].any?{|k,| /\Agraph_/ =~ k}
opts[:allow_eager_graph] = false
end
opts
end
end
end
end
end
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