Add config.disable_sandbox option to Rails console

A long-running `rails console --sandbox` could cause a database server
to become out-of-memory as it's holding on to changes that happen on the
database.

Given that it's common for Ruby on Rails application with huge
traffic to have separate write database and read database, we should
allow the developers to disable this sandbox option to prevent someone
from accidentally causing the Denial-of-Service on their server.

2 files changed, 34 insertions, 3 deletions

diff --git a/railties/test/application/configuration_test.rb b/railties/test/application/configuration_test.rb
index e34c075a1c..b8e167b488 100644
--- a/railties/test/application/configuration_test.rb
+++ b/railties/test/application/configuration_test.rb
@@ -2476,6 +2476,22 @@ module ApplicationTests
       assert_includes Rails.application.config.hosts, ".localhost"
     end
 
+    test "disable_sandbox is false by default" do
+      app "development"
+
+      assert_equal false, Rails.configuration.disable_sandbox
+    end
+
+    test "disable_sandbox can be overridden" do
+      add_to_config <<-RUBY
+        config.disable_sandbox = true
+      RUBY
+
+      app "development"
+
+      assert Rails.configuration.disable_sandbox
+    end
+
     private
       def force_lazy_load_hooks
         yield # Tasty clarifying sugar, homie! We only need to reference a constant to load it.
diff --git a/railties/test/application/console_test.rb b/railties/test/application/console_test.rb
index b6270525f0..db16f4cc56 100644
--- a/railties/test/application/console_test.rb
+++ b/railties/test/application/console_test.rb
@@ -123,13 +123,17 @@ class FullStackConsoleTest < ActiveSupport::TestCase
     assert_output "> ", @primary
   end
 
-  def spawn_console(options)
-    Process.spawn(
+  def spawn_console(options, wait_for_prompt: true)
+    pid = Process.spawn(
       "#{app_path}/bin/rails console #{options}",
       in: @replica, out: @replica, err: @replica
     )
 
-    assert_output "> ", @primary, 30
+    if wait_for_prompt
+      assert_output "> ", @primary, 30
+    end
+
+    pid
   end
 
   def test_sandbox
@@ -148,6 +152,17 @@ class FullStackConsoleTest < ActiveSupport::TestCase
     @primary.puts "quit"
   end
 
+  def test_sandbox_when_sandbox_is_disabled
+    add_to_config <<-RUBY
+      config.disable_sandbox = true
+    RUBY
+
+    output = `#{app_path}/bin/rails console --sandbox`
+
+    assert_includes output, "sandbox mode is disabled"
+    assert_equal 1, $?.exitstatus
+  end
+
   def test_environment_option_and_irb_option
     spawn_console("-e test -- --verbose")