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|
# frozen_string_literal: true
require_dependency 'gitlab/utils'
require_dependency 'gitlab/environment'
module Gitlab
module Utils
module Override
class Extension
def self.verify_class!(klass, method_name, arity)
extension = new(klass)
parents = extension.parents_for(klass)
extension.verify_method!(
klass: klass, parents: parents, method_name: method_name, sub_method_arity: arity)
end
attr_reader :subject
def initialize(subject)
@subject = subject
end
def parents_for(klass)
index = klass.ancestors.index(subject)
klass.ancestors.drop(index + 1)
end
def verify!
classes.each do |klass|
parents = parents_for(klass)
method_names.each_pair do |method_name, arity|
verify_method!(
klass: klass,
parents: parents,
method_name: method_name,
sub_method_arity: arity)
end
end
end
def verify_method!(klass:, parents:, method_name:, sub_method_arity:)
overridden_parent = parents.find do |parent|
instance_method_defined?(parent, method_name)
end
raise NotImplementedError, "#{klass}\##{method_name} doesn't exist!" unless overridden_parent
super_method_arity = find_direct_method(overridden_parent, method_name).arity
unless arity_compatible?(sub_method_arity, super_method_arity)
raise NotImplementedError, "#{subject}\##{method_name} has arity of #{sub_method_arity}, but #{overridden_parent}\##{method_name} has arity of #{super_method_arity}"
end
end
def add_method_name(method_name, arity = nil)
method_names[method_name] = arity
end
def add_class(klass)
classes << klass
end
def verify_override?(method_name)
method_names.has_key?(method_name)
end
private
def instance_method_defined?(klass, name)
klass.method_defined?(name, false) ||
klass.private_method_defined?(name, false)
end
def find_direct_method(klass, name)
method = klass.instance_method(name)
method = method.super_method until method && klass == method.owner
method
end
def arity_compatible?(sub_method_arity, super_method_arity)
if sub_method_arity >= 0 && super_method_arity >= 0
# Regular arguments
sub_method_arity == super_method_arity
else
# It's too complex to check this case, just allow sub-method having negative arity
# But we don't allow sub_method_arity > 0 yet super_method_arity < 0
sub_method_arity < 0
end
end
def method_names
@method_names ||= {}
end
def classes
@classes ||= []
end
end
# Instead of writing patterns like this:
#
# def f
# raise NotImplementedError unless defined?(super)
#
# true
# end
#
# We could write it like:
#
# extend ::Gitlab::Utils::Override
#
# override :f
# def f
# true
# end
#
# This would make sure we're overriding something. See:
# https://gitlab.com/gitlab-org/gitlab/issues/1819
def override(method_name)
return unless Gitlab::Environment.static_verification?
Override.extensions[self] ||= Extension.new(self)
Override.extensions[self].add_method_name(method_name)
end
def method_added(method_name)
super
return unless Gitlab::Environment.static_verification?
return unless Override.extensions[self]&.verify_override?(method_name)
method_arity = instance_method(method_name).arity
if is_a?(Class)
Extension.verify_class!(self, method_name, method_arity)
else # We delay the check for modules
Override.extensions[self].add_method_name(method_name, method_arity)
end
end
def included(base = nil)
super
queue_verification(base) if base
end
def prepended(base = nil)
super
# prepend can override methods, thus we need to verify it like classes
queue_verification(base, verify: true) if base
end
def extended(mod = nil)
super
# Hack to resolve https://gitlab.com/gitlab-org/gitlab/-/issues/23932
is_not_concern_hack =
(mod.is_a?(Class) || !name&.end_with?('::ClassMethods'))
if mod && is_not_concern_hack
queue_verification(mod.singleton_class)
end
end
def queue_verification(base, verify: false)
return unless Gitlab::Environment.static_verification?
# We could check for Class in `override`
# This could be `nil` if `override` was never called.
# We also force verification for prepend because it can also override
# a method like a class, but not the cases for include or extend.
# This includes Rails helpers but not limited to.
if base.is_a?(Class) || verify
Override.extensions[self]&.add_class(base)
end
end
def self.extensions
@extensions ||= {}
end
def self.verify!
extensions.each_value(&:verify!)
end
end
end
end
|
