Fixes #63 ("nop splice removes element")

doc/intrusive.qbk

@@ -3894,6 +3894,7 @@ to be inserted in intrusive containers are allocated using `std::vector` or `std
    * [@https://github.com/boostorg/intrusive/pull/57   GitHub #57: ['UB: comparing unrelated pointers]]
    * [@https://github.com/boostorg/intrusive/issues/59 GitHub #59: ['Add noexcept support to the library]]
    * [@https://github.com/boostorg/intrusive/issues/60 GitHub #60: ['Licensing question for math.hpp]]
+   * [@https://github.com/boostorg/intrusive/issues/63 GitHub #63: ['nop splice removes element]]
 
 [endsect]
 

include/boost/intrusive/circular_list_algorithms.hpp

@@ -253,7 +253,7 @@ class circular_list_algorithms
    //! <b>Throws</b>: Nothing.
    static void transfer(node_ptr p, node_ptr b, node_ptr e) BOOST_NOEXCEPT
    {
-      if (b != e) {
+      if (b != e && p != b && p != e) {
          node_ptr prev_p(NodeTraits::get_previous(p));
          node_ptr prev_b(NodeTraits::get_previous(b));
          node_ptr prev_e(NodeTraits::get_previous(e));

test/list_test.cpp

@@ -273,7 +273,7 @@ template < class ListType, typename ValueContainer >
 void test_list< ListType, ValueContainer >
    ::test_swap(ValueContainer& values)
 {
-   {
+   {  //splice between two lists
       list_type testlist1 (values.begin(), values.begin() + 2);
       list_type testlist2;
       testlist2.insert (testlist2.end(), values.begin() + 2, values.begin() + 5);
@@ -308,6 +308,41 @@ void test_list< ListType, ValueContainer >
       BOOST_TEST (testlist1.size() == 1);
       BOOST_TEST (&testlist1.front() == &values[3]);
    }
+
+   {  //splice in the same list
+      list_type testlist1 (values.begin(), values.begin() + 5);
+
+      {  int init_values [] = { 1, 2, 3, 4, 5 };
+         TEST_INTRUSIVE_SEQUENCE( init_values, testlist1.begin() );  }
+
+      //nop 1
+      testlist1.splice (testlist1.begin(), testlist1, testlist1.begin(), ++testlist1.begin());
+      {  int init_values [] = { 1, 2, 3, 4, 5 };
+         TEST_INTRUSIVE_SEQUENCE( init_values, testlist1.begin() );  }
+
+      //nop 2
+      testlist1.splice (++testlist1.begin(), testlist1, testlist1.begin(), ++testlist1.begin());
+      {  int init_values [] = { 1, 2, 3, 4, 5 };
+         TEST_INTRUSIVE_SEQUENCE( init_values, testlist1.begin() );  }
+
+      //nop 3
+      testlist1.splice (testlist1.begin(), testlist1, ++testlist1.begin(), ++testlist1.begin());
+      {  int init_values [] = { 1, 2, 3, 4, 5 };
+         TEST_INTRUSIVE_SEQUENCE( init_values, testlist1.begin() );  }
+
+      testlist1.splice (testlist1.begin(), testlist1, ++testlist1.begin(), ++++testlist1.begin());
+      {  int init_values [] = { 2, 1, 3, 4, 5 };
+         TEST_INTRUSIVE_SEQUENCE( init_values, testlist1.begin() );  }
+
+      testlist1.splice (testlist1.begin(), testlist1, ++testlist1.begin(), ++++++testlist1.begin());
+      {  int init_values [] = { 1, 3, 2, 4, 5 };
+         TEST_INTRUSIVE_SEQUENCE( init_values, testlist1.begin() );  }
+
+      testlist1.splice (++++++++testlist1.begin(), testlist1, testlist1.begin(), ++++testlist1.begin());
+      {  int init_values [] = { 2, 4, 1, 3, 5 };
+         TEST_INTRUSIVE_SEQUENCE( init_values, testlist1.begin() );  }
+   }
+
    {
       list_type testlist1 (values.begin(), values.begin() + 2);
       list_type testlist2 (values.begin() + 3, values.begin() + 5);

test/slist_test.cpp

@@ -354,6 +354,41 @@ void test_slist< ListType, ValueContainer >
       {  int init_values [] = { 2 };
          TEST_INTRUSIVE_SEQUENCE( init_values, testlist2.begin() );  }
    }
+
+   {  //splice in the same list
+      list_type testlist1 (values.begin(), values.begin() + 5);
+
+      {  int init_values [] = { 1, 2, 3, 4, 5 };
+         TEST_INTRUSIVE_SEQUENCE( init_values, testlist1.begin() );  }
+
+      //nop 1
+      testlist1.splice_after (testlist1.before_begin(), testlist1, testlist1.before_begin(), ++testlist1.before_begin());
+      {  int init_values [] = { 1, 2, 3, 4, 5 };
+         TEST_INTRUSIVE_SEQUENCE( init_values, testlist1.begin() );  }
+
+      //nop 2
+      testlist1.splice_after (++testlist1.before_begin(), testlist1, testlist1.before_begin(), ++testlist1.before_begin());
+      {  int init_values [] = { 1, 2, 3, 4, 5 };
+         TEST_INTRUSIVE_SEQUENCE( init_values, testlist1.begin() );  }
+
+      //nop 3
+      testlist1.splice_after (testlist1.before_begin(), testlist1, ++testlist1.before_begin(), ++testlist1.before_begin());
+      {  int init_values [] = { 1, 2, 3, 4, 5 };
+         TEST_INTRUSIVE_SEQUENCE( init_values, testlist1.begin() );  }
+
+      testlist1.splice_after (testlist1.before_begin(), testlist1, ++testlist1.before_begin(), ++++testlist1.before_begin());
+      {  int init_values [] = { 2, 1, 3, 4, 5 };
+         TEST_INTRUSIVE_SEQUENCE( init_values, testlist1.begin() );  }
+
+      testlist1.splice_after (testlist1.before_begin(), testlist1, ++testlist1.before_begin(), ++++++testlist1.before_begin());
+      {  int init_values [] = { 1, 3, 2, 4, 5 };
+         TEST_INTRUSIVE_SEQUENCE( init_values, testlist1.begin() );  }
+
+      testlist1.splice_after (++++++++testlist1.before_begin(), testlist1, testlist1.before_begin(), ++++testlist1.before_begin());
+      {  int init_values [] = { 2, 4, 1, 3, 5 };
+         TEST_INTRUSIVE_SEQUENCE( init_values, testlist1.begin() );  }
+   }
+
    {  //Now test swap when testlist2 is empty
       list_type testlist1 (values.begin(), values.begin() + 2);
       list_type testlist2;