66 lines
2.1 KiB
Ruby
66 lines
2.1 KiB
Ruby
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# frozen_string_literal: true
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# Add support for writing recursive CTEs in ActiveRecord
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# Initially from Lorin Thwaits (https://github.com/lorint) as per comment:
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# https://github.com/vlado/activerecord-cte/issues/16#issuecomment-1433043310
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# Modified from the above code to change the signature to
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# `with_recursive(hash)` and extending CTE hash values to also includes arrays
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# of values that get turned into UNION ALL expressions.
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# This implementation has been merged in Rails: https://github.com/rails/rails/pull/51601
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module ActiveRecord
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module QueryMethodsExtensions
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def with_recursive(*args)
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@with_is_recursive = true
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check_if_method_has_arguments!(__callee__, args)
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spawn.with_recursive!(*args)
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end
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# Like #with_recursive but modifies the relation in place.
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def with_recursive!(*args) # :nodoc:
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self.with_values += args
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@with_is_recursive = true
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self
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end
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private
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def build_with(arel)
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return if with_values.empty?
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with_statements = with_values.map do |with_value|
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raise ArgumentError, "Unsupported argument type: #{with_value} #{with_value.class}" unless with_value.is_a?(Hash)
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build_with_value_from_hash(with_value)
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end
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# Was: arel.with(with_statements)
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@with_is_recursive ? arel.with(:recursive, with_statements) : arel.with(with_statements)
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end
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def build_with_value_from_hash(hash)
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hash.map do |name, value|
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Arel::Nodes::TableAlias.new(build_with_expression_from_value(value), name)
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end
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end
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def build_with_expression_from_value(value)
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case value
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when Arel::Nodes::SqlLiteral then Arel::Nodes::Grouping.new(value)
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when ActiveRecord::Relation then value.arel
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when Arel::SelectManager then value
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when Array then value.map { |e| build_with_expression_from_value(e) }.reduce { |result, value| Arel::Nodes::UnionAll.new(result, value) }
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else
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raise ArgumentError, "Unsupported argument type: `#{value}` #{value.class}"
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end
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end
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end
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end
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ActiveSupport.on_load(:active_record) do
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ActiveRecord::QueryMethods.prepend(ActiveRecord::QueryMethodsExtensions)
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end
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