mkmf.rb: fix merge_libs

* lib/mkmf.rb (MakeMakefile#merge_libs): insert following reversal
  ordered elements just after the duplicated element, not overwriting
  successive elements.  [ruby-core:50314] [Bug #7467]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39128 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

3 files changed, 29 insertions, 8 deletions

diff --git a/ChangeLog b/ChangeLog
index 65b553ae08..f15db14816 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Thu Feb  7 15:33:17 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* lib/mkmf.rb (MakeMakefile#merge_libs): insert following reversal
+	  ordered elements just after the duplicated element, not overwriting
+	  successive elements.  [ruby-core:50314] [Bug #7467]
+
 Thu Feb  7 14:56:15 2013  Eric Hodel  <drbrain@segment7.net>
 
 	* lib/rubygems/package.rb:  Ensure digests are generated for signing.
diff --git a/lib/mkmf.rb b/lib/mkmf.rb
index a33bb4c933..226bb301fb 100644
--- a/lib/mkmf.rb
+++ b/lib/mkmf.rb
@@ -269,17 +269,15 @@ module MakeMakefile
 
   def merge_libs(*libs)
     libs.inject([]) do |x, y|
-      xy = x & y
-      xn = yn = 0
       y = y.inject([]) {|ary, e| ary.last == e ? ary : ary << e}
       y.each_with_index do |v, yi|
-        if xy.include?(v)
-          xi = [x.index(v), xn].max()
-          x[xi, 1] = y[yn..yi]
-          xn, yn = xi + (yi - yn + 1), yi + 1
+        if xi = x.rindex(v)
+          x[(xi+1)..-1] = merge_libs(y[(yi+1)..-1], x[(xi+1)..-1])
+          x[xi, 0] = y[0...yi]
+          break
         end
-      end
-      x.concat(y[yn..-1] || [])
+      end and x.concat(y)
+      x
     end
   end
 
diff --git a/test/mkmf/test_libs.rb b/test/mkmf/test_libs.rb
index 67722afa67..27674dfd26 100644
--- a/test/mkmf/test_libs.rb
+++ b/test/mkmf/test_libs.rb
@@ -65,5 +65,22 @@ class TestMkmf
       assert_in_order(array, "c", "d" , bug)
       ## assume that a and c have no dependency
     end
+
+    def test_merge_reversal_followed
+      bug7467 = '[ruby-core:50314] [Bug #7467]'
+      array = nil
+      assert_nothing_raised(bug7467) {
+        array = merge_libs(%w[a b c d e f g h], %w[d c d e], [])
+      }
+      assert_in_order(array, "a", "b", bug7467)
+      assert_in_order(array, "b", "c", bug7467)
+      assert_in_order(array, "c", "d", bug7467)
+      assert_in_order(array, "d", "e", bug7467)
+      assert_in_order(array, "e", "f", bug7467)
+      assert_in_order(array, "f", "g", bug7467)
+      assert_in_order(array, "g", "h", bug7467)
+      assert_in_order(array, "d", "c", bug7467)
+      assert_in_order(array, "c", "e", bug7467)
+    end
   end
 end if RUBY_ENGINE == "ruby"