Run each spec file in a process to detect missing requires

* Fixes ruby-concurrency#934.

Gemfile

@@ -2,7 +2,6 @@ source 'https://rubygems.org'
 
 require File.join(File.dirname(__FILE__), 'lib/concurrent-ruby/concurrent/version')
 require File.join(File.dirname(__FILE__ ), 'lib/concurrent-ruby-edge/concurrent/edge/version')
-require File.join(File.dirname(__FILE__ ), 'lib/concurrent-ruby/concurrent/utility/engine')
 
 no_path = ENV['NO_PATH']
 options = no_path ? {} : { path: '.' }

README.md

@@ -271,6 +271,7 @@ Everything within this gem can be loaded simply by requiring it:
 require 'concurrent'
 ```
 
+TODO: update this
 *Requiring only specific abstractions from Concurrent Ruby is not yet supported.*
 
 To use the tools in the Edge gem it must be required separately:

concurrent-ruby.gemspec

@@ -1,5 +1,4 @@
 require File.join(File.dirname(__FILE__ ), 'lib/concurrent-ruby/concurrent/version')
-require File.join(File.dirname(__FILE__ ), 'lib/concurrent-ruby/concurrent/utility/engine')
 
 Gem::Specification.new do |s|
   git_files = `git ls-files`.split("\n")

deps.md

@@ -0,0 +1,13 @@
+Currently:
+* lib/concurrent-ruby/concurrent/synchronization.rb loads C exts
+* require 'concurrent/synchronization/*' seems not supported, too deep, and relies on require 'concurrent/synchronization' instead (seems OK).
+
+A cycle:
+AtomicMarkableReference -> Synchronization::Object
+
+Synchronization::Object (synchronization/object.rb) -> AtomicReference
+AtomicReference -> MutexAtomicReference (but only if non-cruby/jruby/tuffleruby)
+MutexAtomicReference -> Synchronization::LockableObject
+Synchronization::LockableObject -> MutexLockableObject, JRubyLockableObject, MonitorLockableObject
+MutexLockableObject -> AbstractLockableObject
+AbstractLockableObject -> Synchronization::Object

lib/concurrent-ruby/concurrent/atomic/atomic_markable_reference.rb

@@ -1,3 +1,5 @@
+require 'concurrent/synchronization'
+
 module Concurrent
   # An atomic reference which maintains an object reference along with a mark bit
   # that can be updated atomically.

lib/concurrent-ruby/concurrent/atomic/atomic_reference.rb

@@ -1,4 +1,4 @@
-require 'concurrent/synchronization'
+require 'concurrent/synchronization' # NEEDED?
 require 'concurrent/utility/engine'
 require 'concurrent/atomic_reference/numeric_cas_wrapper'
 

spec/concurrent/agent_spec.rb

@@ -1,3 +1,9 @@
+require 'concurrent/agent'
+require 'concurrent/executor/single_thread_executor'
+require 'concurrent/executor/immediate_executor'
+require 'concurrent/executor/fixed_thread_pool'
+require 'concurrent/atomic/count_down_latch'
+
 require_relative 'concern/observable_shared'
 
 module Concurrent

spec/concurrent/array_spec.rb

@@ -1,3 +1,5 @@
+require 'concurrent/array'
+
 module Concurrent
   RSpec.describe Array do
     let!(:ary) { described_class.new }

spec/concurrent/async_spec.rb

@@ -1,5 +1,6 @@
-module Concurrent
+require 'concurrent/async'
 
+module Concurrent
   RSpec.describe Async do
 
     let(:async_class) do

spec/concurrent/atomic/atomic_boolean_spec.rb

@@ -1,3 +1,5 @@
+require 'concurrent/atomic/atomic_boolean'
+
 RSpec.shared_examples :atomic_boolean do
 
   describe 'construction' do

spec/concurrent/atomic/atomic_fixnum_spec.rb

@@ -1,3 +1,5 @@
+require 'concurrent/atomic/atomic_fixnum'
+
 RSpec.shared_examples :atomic_fixnum do
 
   context 'construction' do

spec/concurrent/atomic/atomic_markable_reference_spec.rb

@@ -1,3 +1,5 @@
+require 'concurrent/atomic/atomic_markable_reference'
+
 RSpec.describe Concurrent::AtomicMarkableReference do
   subject { described_class.new 1000, true }
 

spec/concurrent/no_concurrent_files_loaded_before_spec.rb

@@ -0,0 +1,7 @@
+files_loaded_before = $LOADED_FEATURES.grep(/\/concurrent\//).grep_v(/\/version\.rb$/)
+
+RSpec.describe 'The test harness' do
+  it 'does not load concurrent-ruby files to ensure there are no missing requires' do
+    expect(files_loaded_before).to eq []
+  end
+end

spec/spec_helper.rb

@@ -26,11 +26,6 @@ def requires=(paths)
   end
 end
 
-require 'concurrent'
-require 'concurrent-edge'
-
-Concurrent.use_simple_logger Logger::FATAL
-
 require_relative 'support/example_group_extensions'
 require_relative 'support/threadsafe_test'
 
@@ -44,6 +39,13 @@ def requires=(paths)
   config.include Concurrent::TestHelpers
   config.extend Concurrent::TestHelpers
 
+  config.before :all do
+    # Only configure logging if it has been required, to make sure the necessary require's are in place
+    if Concurrent.respond_to? :use_simple_logger
+      Concurrent.use_simple_logger Logger::FATAL
+    end
+  end
+
   config.before :each do
     expect(!defined?(@created_threads) || @created_threads.nil? || @created_threads.empty?).to be_truthy
   end

spec/support/example_group_extensions.rb

@@ -1,5 +1,4 @@
 require 'rbconfig'
-require 'concurrent/synchronization'
 
 module Concurrent
   module TestHelpers
@@ -17,7 +16,7 @@ def delta(v1, v2)
       return (v1 - v2).abs
     end
 
-    include Utility::EngineDetector
+    # include Utility::EngineDetector # TODO
 
     def use_c_extensions?
       Concurrent.allow_c_extensions?