Fix error with empty args.

* ext/pathname/lib/pathname.rb (Pathname#join): Fix error with
  empty args. Reported by ko1 via IRC.

* test/pathname/test_pathname.rb (TestPathname#test_join): Add the
  test for above case.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45499 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,11 @@
+Wed Apr  2 11:46:29 2014  Kazuhiro NISHIYAMA  <[email protected]>
+
+	* ext/pathname/lib/pathname.rb (Pathname#join): Fix error with
+	  empty args. Reported by ko1 via IRC.
+
+	* test/pathname/test_pathname.rb (TestPathname#test_join): Add the
+	  test for above case.
+
 Tue Apr  1 11:39:57 2014  James Edward Gray II  <[email protected]>
 
 	* lib/csv.rb: Symbol HeaderConverter: strip leading/trailing space.

ext/pathname/lib/pathname.rb

@@ -384,6 +384,7 @@ def plus(path1, path2) # -> path # :nodoc:
   #       #=> true
   #
   def join(*args)
+    return self if args.empty?
     result = args.pop
     result = Pathname.new(result) unless Pathname === result
     return result if result.absolute?

test/pathname/test_pathname.rb

@@ -242,6 +242,8 @@ def test_join
     assert_equal(Pathname("/c"), r)
     r = Pathname("/a").join("/b", "/c")
     assert_equal(Pathname("/c"), r)
+    r = Pathname("/foo/var").join()
+    assert_equal(Pathname("/foo/var"), r)
   end
 
   def test_absolute