merge revision(s) 59102: [Backport #13515]

pathname.rb: UNC root pathname needs a separator

	* ext/pathname/lib/pathname.rb (Pathname#plus): UNC root pathname
	  needs a separator.  File.basename returns "/" on UNC root, as
	  well as sole drive letter, even if it does not end with a
	  separator.  [ruby-core:80900] [Bug #13515]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_4@59400 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ext/pathname/lib/pathname.rb

@@ -378,7 +378,7 @@ class Pathname
       basename_list2.shift
     end
     r1 = chop_basename(prefix1)
-    if !r1 && /#{SEPARATOR_PAT}/o =~ File.basename(prefix1)
+    if !r1 && (r1 = /#{SEPARATOR_PAT}/o =~ File.basename(prefix1))
       while !basename_list2.empty? && basename_list2.first == '..'
         index_list2.shift
         basename_list2.shift

test/pathname/test_pathname.rb

@@ -14,8 +14,8 @@ class TestPathname < Test::Unit::TestCase
   end
 
   def self.get_linenum
-    if /:(\d+):/ =~ caller[1]
-      $1.to_i
+    if loc = caller_locations(2, 1)
+      loc[0].lineno
     else
       nil
     end
@@ -221,6 +221,8 @@ class TestPathname < Test::Unit::TestCase
 
   defassert(:plus, 'a//b/d//e', 'a//b/c', '../d//e')
 
+  defassert(:plus, '//foo/var/bar', '//foo/var', 'bar')
+
   def test_slash
     assert_kind_of(Pathname, Pathname("a") / Pathname("b"))
   end

version.h

@@ -1,6 +1,6 @@
 #define RUBY_VERSION "2.4.2"
 #define RUBY_RELEASE_DATE "2017-07-23"
-#define RUBY_PATCHLEVEL 151
+#define RUBY_PATCHLEVEL 152
 
 #define RUBY_RELEASE_YEAR 2017
 #define RUBY_RELEASE_MONTH 7