Drop support for Rails 4.0 and 4.1

* Bump version to 2.0.0 because this will be a kind of "breaking change"
* Add 'runtime' dependency on activesupport >= 4.2 to gemfile so that
  Spring 2.0.0 won't be installed by bundler in a Rails 4.0 or 4.1
  application (the dependency isn't actually used at runtime)

.travis.yml

@@ -8,8 +8,6 @@ rvm:
   - 2.2.0
   - 2.3.0
 env:
-  - RAILS_VERSION="~> 4.0.0"
-  - RAILS_VERSION="~> 4.1.0"
   - RAILS_VERSION="~> 4.2.0"
 before_script:
   - "[ $TRAVIS_RUBY_VERSION = \"1.9.3\" ] && travis_retry gem install mime-types --version \"~> 2\" || true"

CHANGELOG.md

@@ -1,3 +1,7 @@
+## 2.0.0 (unreleased)
+
+* Drop Rails 4.0 and 4.1 support
+
 ## 1.7.2
 
 * Use `Spring.failsafe_thread` to prevent threads from aborting process due to `Thread.abort_on_exception` when set to `true`

Gemfile

@@ -2,3 +2,7 @@ source 'https://rubygems.org'
 
 # Specify your gem's dependencies in spring.gemspec
 gemspec
+
+if ENV["RAILS_VERSION"]
+  gem "activesupport", ENV["RAILS_VERSION"]
+end

README.md

@@ -17,7 +17,8 @@ boot it every time you run a test, rake task or migration.
 ## Compatibility
 
 * Ruby versions: MRI 1.9.3, MRI 2.0, MRI 2.1, MRI 2.2
-* Rails versions: 4.0+ (in Rails 4.1 and up Spring is included by default)
+* Rails versions: 4.2 (Spring is installed by default when you do `rails
+  new` to generate your application)
 
 Spring makes extensive use of `Process.fork`, so won't be able to
 provide a speed up on platforms which don't support forking (Windows, JRuby).

lib/spring/binstub.rb

@@ -1,6 +1,26 @@
 command  = File.basename($0)
 bin_path = File.expand_path("../../../bin/spring", __FILE__)
 
+# When we run a command which does not go through Spring (e.g. DISABLE_SPRING
+# is used, or we just call 'rails' or something) then we get this warning from
+# Rubygems:
+#
+#   WARN: Unresolved specs during Gem::Specification.reset: activesupport (<= 5.1, >= 4.2)
+#   WARN: Clearing out unresolved specs.
+#   Please report a bug if this causes problems.
+#
+# This happens due to our dependency on activesupport, when Bundler.setup gets
+# called.  We don't actually *use* the dependency; it is purely there to
+# restrict the Rails version that we're compatible with.
+#
+# When the warning is shown, Rubygems just does the below.
+# Therefore, by doing it ourselves here, we can avoid the warning.
+if Gem::Specification.respond_to?(:unresolved_deps)
+  Gem::Specification.unresolved_deps.clear
+else
+  Gem.unresolved_deps.clear
+end
+
 if command == "spring"
   load bin_path
 else

lib/spring/test/acceptance_test.rb

@@ -540,6 +540,11 @@ def exec_name
 
         assert_failure "bin/rails runner ''", stderr: "timed out"
       end
+
+      test "no warnings are shown for unsprung commands" do
+        app.env["DISABLE_SPRING"] = "1"
+        refute_output_includes "bin/rails runner ''", stderr: "WARN"
+      end
     end
   end
 end

lib/spring/test/application.rb

@@ -65,7 +65,7 @@ def rails_version
       end
 
       def spring_test_command
-        "#{rails_version.test_command} #{test}"
+        "bin/rake test #{test}"
       end
 
       def stop_spring
@@ -74,7 +74,7 @@ def stop_spring
       end
 
       def test
-        path "test/#{rails_version.controller_tests_dir}/posts_controller_test.rb"
+        path "test/controllers/posts_controller_test.rb"
       end
 
       def controller

lib/spring/test/application_generator.rb

@@ -48,8 +48,7 @@ def generate_files
 
         @version = RailsVersion.new(`ruby -e 'puts Gem::Specification.find_by_name("rails", "#{version_constraint}").version'`.chomp)
 
-        skips = %w(--skip-bundle --skip-javascript --skip-sprockets)
-        skips << "--skip-spring" if version.bundles_spring?
+        skips = %w(--skip-bundle --skip-javascript --skip-sprockets --skip-spring)
 
         system("rails _#{version}_ new #{application.root} #{skips.join(' ')}")
         raise "application generation failed" unless application.exists?
@@ -60,14 +59,6 @@ def generate_files
 
         append_to_file(application.gemfile, "gem 'spring', '#{Spring::VERSION}'")
 
-        if version.needs_testunit?
-          append_to_file(application.gemfile, "gem 'spring-commands-testunit'")
-        end
-
-        if RUBY_VERSION == "1.9.3" && version.to_s.start_with?("4.0")
-          append_to_file(application.gemfile, "gem 'mime-types', '~> 2'")
-        end
-
         rewrite_file(application.gemfile) do |c|
           c.sub!("https://rubygems.org", "http://rubygems.org")
           c.gsub!(/(gem '(byebug|web-console|sdoc|jbuilder)')/, "# \\1")

lib/spring/test/rails_version.rb

@@ -7,23 +7,6 @@ def initialize(string)
         @version = Gem::Version.new(string)
       end
 
-      def rails_3?
-        version < Gem::Version.new("4.0.0")
-      end
-      alias needs_testunit? rails_3?
-
-      def test_command
-        needs_testunit? ? 'bin/testunit' : 'bin/rake test'
-      end
-
-      def controller_tests_dir
-        rails_3? ? 'functional' : 'controllers'
-      end
-
-      def bundles_spring?
-        version.segments.take(2) == [4, 1] || version > Gem::Version.new("4.1")
-      end
-
       def major
         version.segments[0]
       end

lib/spring/version.rb

@@ -1,3 +1,3 @@
 module Spring
-  VERSION = "1.7.2"
+  VERSION = "2.0.0"
 end

spring.gemspec

@@ -13,7 +13,11 @@ Gem::Specification.new do |gem|
   gem.files         = Dir["LICENSE.txt", "README.md", "lib/**/*", "bin/*"]
   gem.executables   = gem.files.grep(%r{^bin/}).map{ |f| File.basename(f) }
 
-  gem.add_development_dependency 'activesupport', '~> 4.2.0'
+  # We don't directly use Active Support (Spring needs to be able to run
+  # without gem dependencies), but this will ensure that this version of
+  # Spring can't be installed alongside an incompatible Rails version.
+  gem.add_dependency 'activesupport', '>= 4.2'
+
   gem.add_development_dependency 'rake'
   gem.add_development_dependency 'bump'
 end