Commit 9e70ff34 authored by Rémy Coutable's avatar Rémy Coutable

Merge branch '1819-override-ce' into 'master'

CE: Override module to specify that we're overriding

See merge request gitlab-org/gitlab-ce!16131
parents c75a8af1 fd54d7a2
......@@ -3,6 +3,7 @@ module ShaAttribute
module ClassMethods
def sha_attribute(name)
return if ENV['STATIC_VERIFICATION']
return unless table_exists?
column = columns.find { |c| c.name == name.to_s }
......
......@@ -87,9 +87,9 @@ still having access the class's implementation with `super`.
There are a few gotchas with it:
- you should always add a `raise NotImplementedError unless defined?(super)`
guard clause in the "overrider" method to ensure that if the method gets
renamed in CE, the EE override won't be silently forgotten.
- you should always [`extend ::Gitlab::Utils::Override`] and use `override` to
guard the "overrider" method to ensure that if the method gets renamed in
CE, the EE override won't be silently forgotten.
- when the "overrider" would add a line in the middle of the CE
implementation, you should refactor the CE method and split it in
smaller methods. Or create a "hook" method that is empty in CE,
......@@ -134,6 +134,9 @@ There are a few gotchas with it:
guards:
``` ruby
module EE::Base
extend ::Gitlab::Utils::Override
override :do_something
def do_something
# Follow the above pattern to call super and extend it
end
......@@ -174,10 +177,11 @@ implementation:
```ruby
module EE
class ApplicationController
def after_sign_out_path_for(resource)
raise NotImplementedError unless defined?(super)
module ApplicationController
extend ::Gitlab::Utils::Override
override :after_sign_out_path_for
def after_sign_out_path_for(resource)
if Gitlab::Geo.secondary?
Gitlab::Geo.primary_node.oauth_logout_url(@geo_logout_state)
else
......@@ -188,6 +192,8 @@ module EE
end
```
[`extend ::Gitlab::Utils::Override`]: utilities.md#override
#### Use self-descriptive wrapper methods
When it's not possible/logical to modify the implementation of a
......@@ -208,8 +214,8 @@ end
In EE, the implementation `ee/app/models/ee/users.rb` would be:
```ruby
override :full_private_access?
def full_private_access?
raise NotImplementedError unless defined?(super)
super || auditor?
end
```
......
......@@ -45,6 +45,51 @@ We developed a number of utilities to ease development.
[:hello, "world", :this, :crushes, "an entire", "hash"]
```
## [`Override`](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/lib/gitlab/utils/override.rb)
* This utility could help us check if a particular method would override
another method or not. It has the same idea of Java's `@Override` annotation
or Scala's `override` keyword. However we only do this check when
`ENV['STATIC_VERIFICATION']` is set to avoid production runtime overhead.
This is useful to check:
* If we have typos in overriding methods.
* If we renamed the overridden methods, making original overriding methods
overrides nothing.
Here's a simple example:
``` ruby
class Base
def execute
end
end
class Derived < Base
extend ::Gitlab::Utils::Override
override :execute # Override check happens here
def execute
end
end
```
This also works on modules:
``` ruby
module Extension
extend ::Gitlab::Utils::Override
override :execute # Modules do not check this immediately
def execute
end
end
class Derived < Base
prepend Extension # Override check happens here, not in the module
end
```
## [`StrongMemoize`](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/lib/gitlab/utils/strong_memoize.rb)
* Memoize the value even if it is `nil` or `false`.
......
module Gitlab
module Utils
module Override
class Extension
def self.verify_class!(klass, method_name)
instance_method_defined?(klass, method_name) ||
raise(
NotImplementedError.new(
"#{klass}\##{method_name} doesn't exist!"))
end
def self.instance_method_defined?(klass, name, include_super: true)
klass.instance_methods(include_super).include?(name) ||
klass.private_instance_methods(include_super).include?(name)
end
attr_reader :subject
def initialize(subject)
@subject = subject
end
def add_method_name(method_name)
method_names << method_name
end
def add_class(klass)
classes << klass
end
def verify!
classes.each do |klass|
index = klass.ancestors.index(subject)
parents = klass.ancestors.drop(index + 1)
method_names.each do |method_name|
parents.any? do |parent|
self.class.instance_method_defined?(
parent, method_name, include_super: false)
end ||
raise(
NotImplementedError.new(
"#{klass}\##{method_name} doesn't exist!"))
end
end
end
private
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-ee/issues/1819
def override(method_name)
return unless ENV['STATIC_VERIFICATION']
if is_a?(Class)
Extension.verify_class!(self, method_name)
else # We delay the check for modules
Override.extensions[self] ||= Extension.new(self)
Override.extensions[self].add_method_name(method_name)
end
end
def included(base = nil)
return super if base.nil? # Rails concern, ignoring it
super
if base.is_a?(Class) # We could check for Class in `override`
# This could be `nil` if `override` was never called
Override.extensions[self]&.add_class(base)
end
end
alias_method :prepended, :included
def self.extensions
@extensions ||= {}
end
def self.verify!
extensions.values.each(&:verify!)
end
end
end
end
......@@ -7,4 +7,9 @@ namespace :dev do
Rake::Task["gitlab:setup"].invoke
Rake::Task["gitlab:shell:setup"].invoke
end
desc "GitLab | Eager load application"
task load: :environment do
Rails.application.eager_load!
end
end
unless Rails.env.production?
namespace :lint do
task :static_verification_env do
ENV['STATIC_VERIFICATION'] = 'true'
end
desc "GitLab | lint | Static verification"
task static_verification: %w[
lint:static_verification_env
dev:load
] do
Gitlab::Utils::Override.verify!
end
desc "GitLab | lint | Lint JavaScript files using ESLint"
task :javascript do
Rake::Task['eslint'].invoke
......
......@@ -10,9 +10,10 @@ tasks = [
%w[bundle exec license_finder],
%w[yarn run eslint],
%w[bundle exec rubocop --parallel],
%w[scripts/lint-conflicts.sh],
%w[bundle exec rake gettext:lint],
%w[scripts/lint-changelog-yaml]
%w[bundle exec rake lint:static_verification],
%w[scripts/lint-changelog-yaml],
%w[scripts/lint-conflicts.sh]
]
failed_tasks = tasks.reduce({}) do |failures, task|
......
require 'spec_helper'
describe Gitlab::Utils::Override do
let(:base) { Struct.new(:good) }
let(:derived) { Class.new(base).tap { |m| m.extend described_class } }
let(:extension) { Module.new.tap { |m| m.extend described_class } }
let(:prepending_class) { base.tap { |m| m.prepend extension } }
let(:including_class) { base.tap { |m| m.include extension } }
let(:klass) { subject }
def good(mod)
mod.module_eval do
override :good
def good
super.succ
end
end
mod
end
def bad(mod)
mod.module_eval do
override :bad
def bad
true
end
end
mod
end
shared_examples 'checking as intended' do
it 'checks ok for overriding method' do
good(subject)
result = klass.new(0).good
expect(result).to eq(1)
described_class.verify!
end
it 'raises NotImplementedError when it is not overriding anything' do
expect do
bad(subject)
klass.new(0).bad
described_class.verify!
end.to raise_error(NotImplementedError)
end
end
shared_examples 'nothing happened' do
it 'does not complain when it is overriding something' do
good(subject)
result = klass.new(0).good
expect(result).to eq(1)
described_class.verify!
end
it 'does not complain when it is not overriding anything' do
bad(subject)
result = klass.new(0).bad
expect(result).to eq(true)
described_class.verify!
end
end
before do
# Make sure we're not touching the internal cache
allow(described_class).to receive(:extensions).and_return({})
end
describe '#override' do
context 'when STATIC_VERIFICATION is set' do
before do
stub_env('STATIC_VERIFICATION', 'true')
end
context 'when subject is a class' do
subject { derived }
it_behaves_like 'checking as intended'
end
context 'when subject is a module, and class is prepending it' do
subject { extension }
let(:klass) { prepending_class }
it_behaves_like 'checking as intended'
end
context 'when subject is a module, and class is including it' do
subject { extension }
let(:klass) { including_class }
it 'raises NotImplementedError because it is not overriding it' do
expect do
good(subject)
klass.new(0).good
described_class.verify!
end.to raise_error(NotImplementedError)
end
it 'raises NotImplementedError when it is not overriding anything' do
expect do
bad(subject)
klass.new(0).bad
described_class.verify!
end.to raise_error(NotImplementedError)
end
end
end
end
context 'when STATIC_VERIFICATION is not set' do
before do
stub_env('STATIC_VERIFICATION', nil)
end
context 'when subject is a class' do
subject { derived }
it_behaves_like 'nothing happened'
end
context 'when subject is a module, and class is prepending it' do
subject { extension }
let(:klass) { prepending_class }
it_behaves_like 'nothing happened'
end
context 'when subject is a module, and class is including it' do
subject { extension }
let(:klass) { including_class }
it 'does not complain when it is overriding something' do
good(subject)
result = klass.new(0).good
expect(result).to eq(0)
described_class.verify!
end
it 'does not complain when it is not overriding anything' do
bad(subject)
result = klass.new(0).bad
expect(result).to eq(true)
described_class.verify!
end
end
end
end
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