logger.rb: Fix handling progname

Because progname was memoized with ||= a logger call that involved
outputting false would be nil. Example code:

  logger = Logger.new(STDOUT)
  logger.info(false)  # => nil

Perform an explicit nil check instead of ||= so that false will be output.

patched by Gavin Miller <gavingmiller@gmail.com> [Fix GH-1667]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@59380 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 3 insertions, 1 deletions

diff --git a/lib/logger.rb b/lib/logger.rb
index 8be1c26664..f572921db4 100644
--- a/lib/logger.rb
+++ b/lib/logger.rb
@@ -457,7 +457,9 @@ class Logger
     if @logdev.nil? or severity < @level
       return true
     end
-    progname ||= @progname
+    if progname.nil?
+      progname = @progname
+    end
     if message.nil?
       if block_given?
         message = yield