Don't supress non-spring load errors in binstub

Without this change, the spring binstub supresses unrelated load errors,
eg. due to errors in initializers or loaded gems. This change causes the
binstub to only ignore a missing spring binary or gem.

This closes #370 and resolves #259.

Author: felixbuenemann

lib/spring/client/binstub.rb

@@ -13,8 +13,10 @@ class Binstub < Command
       # should cause the "unsprung" version of the command to run.
       LOADER = <<CODE
 begin
-  load File.expand_path('../spring', __FILE__)
-rescue LoadError
+  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
 CODE
 

lib/spring/test/acceptance_test.rb

@@ -208,13 +208,22 @@ def exec_name
         assert_success "bin/rake -T", stdout: "rake db:migrate"
       end
 
-      test "binstub when spring is uninstalled" do
+      test "binstub when spring gem is missing" do
         without_gem "spring-#{Spring::VERSION}" do
           File.write(app.gemfile, app.gemfile.read.gsub(/gem 'spring.*/, ""))
           assert_success "bin/rake -T", stdout: "rake db:migrate"
         end
       end
 
+      test "binstub when spring binary is missing" do
+        begin
+          File.rename(app.path("bin/spring"), app.path("bin/spring.bak"))
+          assert_success "bin/rake -T", stdout: "rake db:migrate"
+        ensure
+          File.rename(app.path("bin/spring.bak"), app.path("bin/spring"))
+        end
+      end
+
       test "binstub upgrade" do
         File.write(app.path("bin/rake"), <<-RUBY.strip_heredoc)
           #!/usr/bin/env ruby