diff options
Diffstat (limited to 'rubocop/cop/gitlab/module_with_instance_variables.rb')
-rw-r--r-- | rubocop/cop/gitlab/module_with_instance_variables.rb | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/rubocop/cop/gitlab/module_with_instance_variables.rb b/rubocop/cop/gitlab/module_with_instance_variables.rb new file mode 100644 index 00000000000..5c9cde98512 --- /dev/null +++ b/rubocop/cop/gitlab/module_with_instance_variables.rb @@ -0,0 +1,63 @@ +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, :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, :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 |