8 files changed, 56 insertions, 4 deletions
diff --git a/railties/CHANGELOG.md b/railties/CHANGELOG.md
index 02fdaf09e0..d2662d61da 100644
--- a/railties/CHANGELOG.md
+++ b/railties/CHANGELOG.md
@@ -1,3 +1,10 @@
+*   Generator a `.keep` file in the `tmp` folder by default as many scripts
+    assume the existence of this folder and most would fail if it is absent.
+
+    See #20299.
+
+    *Yoong Kang Lim*, *Sunny Juneja*
+
 *   `config.static_index` configures directory `index.html` filename
 
     Set `config.static_index` to serve a static directory index file not named
diff --git a/railties/lib/rails/generators/rails/app/app_generator.rb b/railties/lib/rails/generators/rails/app/app_generator.rb
index 1047a2c429..152c26860e 100644
--- a/railties/lib/rails/generators/rails/app/app_generator.rb
+++ b/railties/lib/rails/generators/rails/app/app_generator.rb
@@ -141,6 +141,7 @@ module Rails
     end
 
     def tmp
+      empty_directory_with_keep_file "tmp"
       empty_directory "tmp/cache"
       empty_directory "tmp/cache/assets"
     end
diff --git a/railties/lib/rails/generators/rails/app/templates/bin/setup b/railties/lib/rails/generators/rails/app/templates/bin/setup
index 3a5a2cc1e3..0d41f2fe4c 100644
--- a/railties/lib/rails/generators/rails/app/templates/bin/setup
+++ b/railties/lib/rails/generators/rails/app/templates/bin/setup
@@ -25,5 +25,5 @@ chdir APP_ROOT do
   system 'ruby bin/rake log:clear tmp:clear'
 
   puts "\n== Restarting application server =="
-  touch 'tmp/restart.txt'
+  system 'ruby bin/rake restart'
 end
diff --git a/railties/lib/rails/generators/rails/app/templates/gitignore b/railties/lib/rails/generators/rails/app/templates/gitignore
index e4a00ad181..1b8cf8a9fa 100644
--- a/railties/lib/rails/generators/rails/app/templates/gitignore
+++ b/railties/lib/rails/generators/rails/app/templates/gitignore
@@ -15,7 +15,8 @@
 <% end -%>
 # Ignore all logfiles and tempfiles.
 /log/*
+/tmp/*
 <% if keeps? -%>
 !/log/.keep
+!/tmp/.keep
 <% end -%>
-/tmp
diff --git a/railties/lib/rails/tasks/restart.rake b/railties/lib/rails/tasks/restart.rake
index 1e8940b675..f36c86d81b 100644
--- a/railties/lib/rails/tasks/restart.rake
+++ b/railties/lib/rails/tasks/restart.rake
@@ -1,4 +1,5 @@
 desc "Restart app by touching tmp/restart.txt"
 task :restart do
+  FileUtils.mkdir_p('tmp')
   FileUtils.touch('tmp/restart.txt')
 end
diff --git a/railties/test/application/rake/restart_test.rb b/railties/test/application/rake/restart_test.rb
index 35099913fb..4cae199e6b 100644
--- a/railties/test/application/rake/restart_test.rb
+++ b/railties/test/application/rake/restart_test.rb
@@ -13,12 +13,12 @@ module ApplicationTests
       def teardown
         teardown_app
       end
-      
+
       test 'rake restart touches tmp/restart.txt' do
         Dir.chdir(app_path) do
           `rake restart`
           assert File.exist?("tmp/restart.txt")
-          
+
           prev_mtime = File.mtime("tmp/restart.txt")
           sleep(1)
           `rake restart`
@@ -26,6 +26,14 @@ module ApplicationTests
           assert_not_equal prev_mtime, curr_mtime
         end
       end
+
+      test 'rake restart should work even if tmp folder does not exist' do
+        Dir.chdir(app_path) do
+          FileUtils.remove_dir('tmp')
+          `rake restart`
+          assert File.exist?('tmp/restart.txt')
+        end
+      end
     end
   end
 end
diff --git a/railties/test/application/rake_test.rb b/railties/test/application/rake_test.rb
index de14f269df..dd26ec867d 100644
--- a/railties/test/application/rake_test.rb
+++ b/railties/test/application/rake_test.rb
@@ -285,5 +285,12 @@ module ApplicationTests
 
       assert_match(/Hello, World!/, output)
     end
+
+    def test_tmp_clear_should_work_if_folder_missing
+      FileUtils.remove_dir("#{app_path}/tmp")
+      errormsg = Dir.chdir(app_path) { `bundle exec rake tmp:clear` }
+      assert_predicate $?, :success?
+      assert_empty errormsg
+    end
   end
 end
diff --git a/railties/test/generators/app_generator_test.rb b/railties/test/generators/app_generator_test.rb
index 2bfa05a0b8..af1c05cab1 100644
--- a/railties/test/generators/app_generator_test.rb
+++ b/railties/test/generators/app_generator_test.rb
@@ -44,6 +44,7 @@ DEFAULT_APP_FILES = %w(
   vendor/assets
   vendor/assets/stylesheets
   vendor/assets/javascripts
+  tmp
   tmp/cache
   tmp/cache/assets
 )
@@ -606,6 +607,32 @@ class AppGeneratorTest < Rails::Generators::TestCase
     end
   end
 
+  def test_create_keeps
+    run_generator
+    folders_with_keep = %w(
+      app/assets/images
+      app/mailers
+      app/models
+      app/controllers/concerns
+      app/models/concerns
+      lib/tasks
+      lib/assets
+      log
+      test/fixtures
+      test/fixtures/files
+      test/controllers
+      test/mailers
+      test/models
+      test/helpers
+      test/integration
+      tmp
+      vendor/assets/stylesheets
+    )
+    folders_with_keep.each do |folder|
+      assert_file("#{folder}/.keep")
+    end
+  end
+
   def test_psych_gem
     run_generator
     gem_regex = /gem 'psych',\s+'~> 2.0',\s+platforms: :rbx/