Doesn't work with spring

[TylerRick]

Steps to reproduce

1. Check out a Rails app that has spring inserted in the binstubs — for example, this example app:
   https://github.com/TylerRick/exception_notification-rake_example_with_spring/tree/workaround_using_load_in_bin_rake

2. Run bin/rake check:exception

3. Observe that no email is sent

How it's supposed to work

Normally (without spring), what happens is:

• the bin/rake binstub gets loaded first, and
• that is what triggers rake.rb and rake/rake_module.rb (which defines Rake.application) to get loaded.
• Then Bundler.require loads exception_notification-rake gem, which checks that Rake.application is defined and patches Rake::Application#display_error_message

This is evident from the following backtraces taken at those 2 points:

"~/.rubies/ruby-2.6.0/lib/ruby/gems/2.6.0/gems/rake-12.3.2/lib/rake/rake_module.rb:2:in `<top (required)>'",
"~/.rubies/ruby-2.6.0/lib/ruby/gems/2.6.0/gems/rake-12.3.2/lib/rake.rb:44:in `require'",
"~/.rubies/ruby-2.6.0/lib/ruby/gems/2.6.0/gems/rake-12.3.2/lib/rake.rb:44:in `<top (required)>'",
  require "rake/rake_module"
"bin/rake:8:in `require'",
"bin/rake:8:in `<main>'"]
  require 'rake'

(or if using global rake instead of bin/rake binstub:

"~/.rubies/ruby-2.6.0/lib/ruby/gems/2.6.0/gems/rake-12.3.2/lib/rake/rake_module.rb:4:in `<top (required)>'",
"~/.rubies/ruby-2.6.0/lib/ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in `require'",
"~/.rubies/ruby-2.6.0/lib/ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in `require'",
"~/.rubies/ruby-2.6.0/lib/ruby/gems/2.6.0/gems/rake-12.3.2/lib/rake.rb:44:in `<top (required)>'",
  require "rake/rake_module"
"~/.rubies/ruby-2.6.0/lib/ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in `require'",
"~/.rubies/ruby-2.6.0/lib/ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in `require'",
"~/.rubies/ruby-2.6.0/lib/ruby/gems/2.6.0/gems/rake-12.3.2/exe/rake:25:in `<top (required)>'",
"~/.gem/ruby/2.6.0/bin/rake:23:in `load'",
"~/.gem/ruby/2.6.0/bin/rake:23:in `<main>'"]
  load Gem.activate_bin_path('rake', 'rake', version)

)

"exception_notification-rake/lib/exception_notifier/rake/rake_patch.rb:5:in `<top (required)>'",
"exception_notification-rake/lib/exception_notifier/rake.rb:2:in `require'",
"exception_notification-rake/lib/exception_notifier/rake.rb:2:in `<top (required)>'",
"exception_notification-rake/lib/exception_notification/rake.rb:3:in `require'",
"exception_notification-rake/lib/exception_notification/rake.rb:3:in `<top (required)>'",
"~/.rubies/ruby-2.6.0/lib/ruby/2.6.0/bundler/runtime.rb:95:in `require'",
"~/.rubies/ruby-2.6.0/lib/ruby/2.6.0/bundler/runtime.rb:95:in `rescue in block in require'",
"~/.rubies/ruby-2.6.0/lib/ruby/2.6.0/bundler/runtime.rb:72:in `block in require'",
"~/.rubies/ruby-2.6.0/lib/ruby/2.6.0/bundler/runtime.rb:65:in `each'",
"~/.rubies/ruby-2.6.0/lib/ruby/2.6.0/bundler/runtime.rb:65:in `require'",
"~/.rubies/ruby-2.6.0/lib/ruby/2.6.0/bundler.rb:114:in `require'",
"example_app/config/application.rb:7:in `<top (required)>'",
  Bundler.require(*Rails.groups)
"example_app/Rakefile:4:in `require_relative'",
"example_app/Rakefile:4:in `<top (required)>'",
  require_relative 'config/application'
"~/.rubies/ruby-2.6.0/lib/ruby/gems/2.6.0/gems/rake-12.3.2/lib/rake/rake_module.rb:31:in `load'",
"~/.rubies/ruby-2.6.0/lib/ruby/gems/2.6.0/gems/rake-12.3.2/lib/rake/rake_module.rb:31:in `load_rakefile'",
"~/.rubies/ruby-2.6.0/lib/ruby/gems/2.6.0/gems/rake-12.3.2/lib/rake/application.rb:703:in `raw_load_rakefile'",
"~/.rubies/ruby-2.6.0/lib/ruby/gems/2.6.0/gems/rake-12.3.2/lib/rake/application.rb:104:in `block in load_rakefile'",
"~/.rubies/ruby-2.6.0/lib/ruby/gems/2.6.0/gems/rake-12.3.2/lib/rake/application.rb:186:in `standard_exception_handling'",
"~/.rubies/ruby-2.6.0/lib/ruby/gems/2.6.0/gems/rake-12.3.2/lib/rake/application.rb:103:in `load_rakefile'",
"~/.rubies/ruby-2.6.0/lib/ruby/gems/2.6.0/gems/rake-12.3.2/lib/rake/application.rb:82:in `block in run'",
"~/.rubies/ruby-2.6.0/lib/ruby/gems/2.6.0/gems/rake-12.3.2/lib/rake/application.rb:186:in `standard_exception_handling'",
"~/.rubies/ruby-2.6.0/lib/ruby/gems/2.6.0/gems/rake-12.3.2/lib/rake/application.rb:80:in `run'",
"bin/rake:10:in `<main>'"]

How it works instead when using spring

But when using spring:

• spring's preload loads exception_notifier-rake gem before bin/rake is loaded
• exception_notification-rake checks if Rake.application is defined; since it is not, it doesn't patch Rake::Application#display_error_message and so this gem has no effect
• Then the bin/rake binstub gets loaded,
• which triggers rake.rb and rake/rake_module.rb (which defines Rake.application) to get loaded (too late).

Again, you can see this from the backtraces if you wish:

"exception_notification-rake/lib/exception_notifier/rake/rake_patch.rb:5:in `<top (required)>'",
"exception_notification-rake/lib/exception_notifier/rake.rb:2:in `require'",
"exception_notification-rake/lib/exception_notifier/rake.rb:2:in `<top (required)>'",
"exception_notification-rake/lib/exception_notification/rake.rb:3:in `require'",
"exception_notification-rake/lib/exception_notification/rake.rb:3:in `<top (required)>'",
"~/.rubies/ruby-2.6.0/lib/ruby/2.6.0/bundler/runtime.rb:95:in `require'",
"~/.rubies/ruby-2.6.0/lib/ruby/2.6.0/bundler/runtime.rb:95:in `rescue in block in require'",
"~/.rubies/ruby-2.6.0/lib/ruby/2.6.0/bundler/runtime.rb:72:in `block in require'",
"~/.rubies/ruby-2.6.0/lib/ruby/2.6.0/bundler/runtime.rb:65:in `each'",
"~/.rubies/ruby-2.6.0/lib/ruby/2.6.0/bundler/runtime.rb:65:in `require'",
"~/.rubies/ruby-2.6.0/lib/ruby/2.6.0/bundler.rb:114:in `require'",
"example_app/config/application.rb:7:in `<top (required)>'",
  Bundler.require(*Rails.groups)
"ruby/2.6.0/gems/spring-2.0.2/lib/spring/application.rb:92:in `require'",
"ruby/2.6.0/gems/spring-2.0.2/lib/spring/application.rb:92:in `preload'",

"~/.rubies/ruby-2.6.0/lib/ruby/gems/2.6.0/gems/rake-12.3.2/lib/rake/rake_module.rb:2:in `<top (required)>'",
"~/.rubies/ruby-2.6.0/lib/ruby/gems/2.6.0/gems/rake-12.3.2/lib/rake.rb:44:in `<top (required)>'",
"example_app/bin/rake:8:in `<top (required)>'",
  require 'rake'
"~/.gem/ruby/2.6.0/gems/spring-2.0.2/lib/spring/command_wrapper.rb:40:in `call'",
"~/.gem/ruby/2.6.0/gems/spring-2.0.2/lib/spring/application.rb:201:in `block in serve'",

Workaround

One workaround is to add this line to bin/rake:

 require 'rake'
+load 'exception_notifier/rake/rake_patch.rb'
 Rake.application.run

But a better solution is needed that doesn't require modifying the binstubs that spring automatically generated...