Fix querying absolute domain name twice

lib/resolv.rb

@@ -1041,7 +1041,7 @@ def lazy_initialize
               if /\./ =~ hostname
                 @search = [Label.split($')]
               else
-                @search = [[]]
+                @search = []
               end
             end
 
@@ -1084,23 +1084,18 @@ def nameserver_port
       end
 
       def generate_candidates(name)
-        candidates = nil
         name = Name.create(name)
         if name.absolute?
-          candidates = [name]
+          [name]
         else
+          abs = Name.new(name.to_a)
+          search = @search.map {|domain| Name.new(name.to_a + domain)}
           if @ndots <= name.length - 1
-            candidates = [Name.new(name.to_a)]
+            [abs, *search]
           else
-            candidates = []
-          end
-          candidates.concat(@search.map {|domain| Name.new(name.to_a + domain)})
-          fname = Name.create("#{name}.")
-          if !candidates.include?(fname)
-            candidates << fname
+            [*search, abs]
           end
         end
-        return candidates
       end
 
       InitialTimeout = 5

test/resolv/test_dns.rb

@@ -25,18 +25,37 @@ def with_udp(host, port)
     end
   end
 
-  # [ruby-core:65836]
-  def test_resolve_with_2_ndots
-    conf = Resolv::DNS::Config.new :nameserver => ['127.0.0.1'], :ndots => 2
-    assert conf.single?
-
-    candidates = []
-    conf.resolv('example.com') { |candidate, *args|
-      candidates << candidate
-      raise Resolv::DNS::Config::NXDomain
-    }
-    n = Resolv::DNS::Name.create 'example.com.'
-    assert_equal n, candidates.last
+  def test_conf_ndots
+    # ndots defaults to 1
+    conf = Resolv::DNS::Config.new(nameserver: '127.0.0.1', search: ['local'])
+    conf.lazy_initialize
+    candidates = conf.generate_candidates('example.com')
+    assert_equal 2, candidates.size
+    assert_equal 'example.com', candidates[0].to_s
+    assert_equal 'example.com.local', candidates[1].to_s
+
+    # ndots is 2: search path is used first
+    conf = Resolv::DNS::Config.new(nameserver: '127.0.0.1', search: ['local'], ndots: 2)
+    conf.lazy_initialize
+    candidates = conf.generate_candidates('example.com')
+    assert_equal 2, candidates.size
+    assert_equal 'example.com.local', candidates[0].to_s
+    assert_equal 'example.com', candidates[1].to_s
+  end
+
+  def test_conf_search
+    conf = Resolv::DNS::Config.new(nameserver: '127.0.0.1')
+    conf.lazy_initialize
+    candidates = conf.generate_candidates('example.com')
+    assert_equal candidates.size, candidates.uniq.size
+    assert_equal 'example.com', candidates[0].to_s
+
+    conf = Resolv::DNS::Config.new(nameserver: '127.0.0.1', search: ['local'])
+    conf.lazy_initialize
+    candidates = conf.generate_candidates('example.com')
+    assert_equal 2, candidates.size
+    assert_equal 'example.com', candidates[0].to_s
+    assert_equal 'example.com.local', candidates[1].to_s
   end
 
   def test_query_ipv4_address