[ruby/logger] Let File::NULL ("/dev/null", "NUL" etc.) be considered a nil log device

https://github.com/ruby/logger/commit/b42a1b99aa

2 files changed, 6 insertions, 1 deletions

diff --git a/lib/logger.rb b/lib/logger.rb
index f0b99f75a2..4000dae50c 100644
--- a/lib/logger.rb
+++ b/lib/logger.rb
@@ -385,7 +385,7 @@ class Logger
     self.datetime_format = datetime_format
     self.formatter = formatter
     @logdev = nil
-    if logdev
+    if logdev && logdev != File::NULL
       @logdev = LogDevice.new(logdev, shift_age: shift_age,
         shift_size: shift_size,
         shift_period_suffix: shift_period_suffix,
diff --git a/test/logger/test_logger.rb b/test/logger/test_logger.rb
index 521b5627d4..f8cc2e5bd6 100644
--- a/test/logger/test_logger.rb
+++ b/test/logger/test_logger.rb
@@ -378,4 +378,9 @@ class TestLogger < Test::Unit::TestCase
     log = log(logger, :debug) { "msg" }
     assert_nil log.msg
   end
+
+  def test_does_not_instantiate_log_device_for_File_NULL
+    l = Logger.new(File::NULL)
+    assert_nil(l.instance_variable_get(:@logdev))
+  end
 end