gitlab-org--gitlab-foss/rubocop/cop/gitlab/module_with_instance_variables.rb

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module RuboCop
module Cop
module Gitlab
class ModuleWithInstanceVariables < RuboCop::Cop::Cop
MSG = <<~EOL.freeze
Do not use instance variables in a module. Please read this
for the rationale behind it:
https://docs.gitlab.com/ee/development/module_with_instance_variables.html
EOL
def on_module(node)
check_method_definition(node)
# Not sure why some module would have an extra begin wrapping around
node.each_child_node(:begin) do |begin_node|
check_method_definition(begin_node)
end
end
private
def check_method_definition(node)
node.each_child_node(:def) do |definition|
# We allow this pattern:
#
# def f
# @f ||= true
# end
if only_ivar_or_assignment?(definition)
# We don't allow if any other ivar is used
definition.each_descendant(:ivar) do |offense|
add_offense(offense, location: :expression)
end
# We allow initialize method and single ivar
elsif !initialize_method?(definition) && !single_ivar?(definition)
definition.each_descendant(:ivar, :ivasgn) do |offense|
add_offense(offense, location: :expression)
end
end
end
end
def only_ivar_or_assignment?(definition)
node = definition.child_nodes.last
definition.child_nodes.size == 2 &&
node.or_asgn_type? && node.child_nodes.first.ivasgn_type?
end
def single_ivar?(definition)
node = definition.child_nodes.last
definition.child_nodes.size == 2 && node.ivar_type?
end
def initialize_method?(definition)
definition.children.first == :initialize
end
end
end
end
end