Fix uncaught Gem::LoadError in binstub loader

The previous binstub code did not catch Gem::LoadErrors which can
be generated by bundler or rubygems trying to load the spring gem.

This fixes rails#447.

lib/spring/client/binstub.rb

@@ -13,10 +13,9 @@ class Binstub < Command
       # should cause the "unsprung" version of the command to run.
       LOADER = <<CODE
 begin
-  spring_bin_path = File.expand_path('../spring', __FILE__)
-  load spring_bin_path
+  load File.expand_path('../spring', __FILE__)
 rescue LoadError => e
-  raise unless e.message.end_with? spring_bin_path, 'spring/binstub'
+  raise unless e.message.include?('spring')
 end
 CODE
 
@@ -51,6 +50,7 @@ class Binstub < Command
       BINSTUB_VARIATIONS = Regexp.union [
         %{begin\n  load File.expand_path("../spring", __FILE__)\nrescue LoadError\nend\n},
         %{begin\n  load File.expand_path('../spring', __FILE__)\nrescue LoadError\nend\n},
+        %{begin\n  spring_bin_path = File.expand_path('../spring', __FILE__)\n  load spring_bin_path\nrescue LoadError => e\n  raise unless e.message.end_with? spring_bin_path, 'spring/binstub'\nend\n},
         LOADER
       ]
 

lib/spring/test/acceptance_test.rb

@@ -275,6 +275,13 @@ def exec_name
       end
 
       test "binstub upgrade with new binstub variations" do
+        expected = <<-RUBY.gsub(/^          /, "")
+          #!/usr/bin/env ruby
+          #{Spring::Client::Binstub::LOADER.strip}
+          require 'bundler/setup'
+          load Gem.bin_path('rake', 'rake')
+        RUBY
+
         # older variation with double quotes
         File.write(app.path("bin/rake"), <<-RUBY.strip_heredoc)
           #!/usr/bin/env ruby
@@ -286,36 +293,38 @@ def exec_name
           load Gem.bin_path('rake', 'rake')
         RUBY
 
+        assert_success "bin/spring binstub rake", stdout: "bin/rake: upgraded"
+        assert_equal expected, app.path("bin/rake").read
+
         # newer variation with single quotes
-        File.write(app.path("bin/rails"), <<-RUBY.strip_heredoc)
+        File.write(app.path("bin/rake"), <<-RUBY.strip_heredoc)
           #!/usr/bin/env ruby
           begin
             load File.expand_path('../spring', __FILE__)
           rescue LoadError
           end
-          APP_PATH = File.expand_path('../../config/application',  __FILE__)
-          require_relative '../config/boot'
-          require 'rails/commands'
+          require 'bundler/setup'
+          load Gem.bin_path('rake', 'rake')
         RUBY
 
-        assert_success "bin/spring binstub --all", stdout: "upgraded"
+        assert_success "bin/spring binstub rake", stdout: "bin/rake: upgraded"
+        assert_equal expected, app.path("bin/rake").read
 
-        expected = <<-RUBY.gsub(/^          /, "")
+        # newer variation which checks end of exception message
+        File.write(app.path("bin/rake"), <<-RUBY.strip_heredoc)
           #!/usr/bin/env ruby
-          #{Spring::Client::Binstub::LOADER.strip}
+          begin
+            spring_bin_path = File.expand_path('../spring', __FILE__)
+            load spring_bin_path
+          rescue LoadError => e
+            raise unless e.message.end_with? spring_bin_path, 'spring/binstub'
+          end
           require 'bundler/setup'
           load Gem.bin_path('rake', 'rake')
         RUBY
-        assert_equal expected, app.path("bin/rake").read
 
-        expected = <<-RUBY.gsub(/^          /, "")
-          #!/usr/bin/env ruby
-          #{Spring::Client::Binstub::LOADER.strip}
-          APP_PATH = File.expand_path('../../config/application',  __FILE__)
-          require_relative '../config/boot'
-          require 'rails/commands'
-        RUBY
-        assert_equal expected, app.path("bin/rails").read
+        assert_success "bin/spring binstub rake", stdout: "bin/rake: upgraded"
+        assert_equal expected, app.path("bin/rake").read
       end
 
       test "binstub remove with new binstub variations" do