Merge branch 'develop'

This should avoid duplicating none instances in all translation units.

Closes https://github.com/boostorg/optional/issues/33.

CMakeLists.txt

@@ -0,0 +1,28 @@
+# Copyright 2019 Mike Dev
+# Distributed under the Boost Software License, Version 1.0.
+# See accompanying file LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt
+#
+# NOTE: CMake support for Boost.Optional is currently experimental at best
+#       and the interface is likely to change in the future
+
+cmake_minimum_required( VERSION 3.5 )
+project( BoostOptional )
+
+add_library( boost_optional INTERFACE )
+add_library( Boost::optional ALIAS boost_optional )
+
+target_include_directories( boost_optional INTERFACE include )
+
+target_link_libraries( boost_optional
+    INTERFACE
+        Boost::assert
+        Boost::config
+        Boost::core
+        Boost::detail
+        Boost::move
+        Boost::predef
+        Boost::static_assert
+        Boost::throw_exception
+        Boost::type_traits
+        Boost::utility
+)

doc/91_relnotes.qbk

@@ -11,6 +11,11 @@
 
 [section:relnotes Release Notes]
 
+[heading Boost Release 1.73]
+
+* Fixed [@https://github.com/boostorg/optional/issues/78 issue #78].
+* `boost::none` is now declared as an inline variable (on compilers taht support it): there is only one instance of `boost::none` across all translation units. 
+
 [heading Boost Release 1.69]
 
 * Remove deprecation mark from `reset()` method (without arguments).

doc/html/boost_optional/relnotes.html

@@ -28,6 +28,21 @@
 </h2></div></div></div>
 <h4>
 <a name="boost_optional.relnotes.h0"></a>
+      <span class="phrase"><a name="boost_optional.relnotes.boost_release_1_73"></a></span><a class="link" href="relnotes.html#boost_optional.relnotes.boost_release_1_73">Boost
+      Release 1.73</a>
+    </h4>
+<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
+<li class="listitem">
+          Fixed <a href="https://github.com/boostorg/optional/issues/78" target="_top">issue
+          #78</a>.
+        </li>
+<li class="listitem">
+          <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">none</span></code> is now declared as an inline variable
+          (on compilers taht support it): there is only one instance of <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">none</span></code> across all translation units.
+        </li>
+</ul></div>
+<h4>
+<a name="boost_optional.relnotes.h1"></a>
       <span class="phrase"><a name="boost_optional.relnotes.boost_release_1_69"></a></span><a class="link" href="relnotes.html#boost_optional.relnotes.boost_release_1_69">Boost
       Release 1.69</a>
     </h4>
@@ -45,7 +60,7 @@
         </li>
 </ul></div>
 <h4>
-<a name="boost_optional.relnotes.h1"></a>
+<a name="boost_optional.relnotes.h2"></a>
       <span class="phrase"><a name="boost_optional.relnotes.boost_release_1_68"></a></span><a class="link" href="relnotes.html#boost_optional.relnotes.boost_release_1_68">Boost
       Release 1.68</a>
     </h4>
@@ -62,7 +77,7 @@
         </li>
 </ul></div>
 <h4>
-<a name="boost_optional.relnotes.h2"></a>
+<a name="boost_optional.relnotes.h3"></a>
       <span class="phrase"><a name="boost_optional.relnotes.boost_release_1_67"></a></span><a class="link" href="relnotes.html#boost_optional.relnotes.boost_release_1_67">Boost
       Release 1.67</a>
     </h4>
@@ -76,7 +91,7 @@
         </li>
 </ul></div>
 <h4>
-<a name="boost_optional.relnotes.h3"></a>
+<a name="boost_optional.relnotes.h4"></a>
       <span class="phrase"><a name="boost_optional.relnotes.boost_release_1_66"></a></span><a class="link" href="relnotes.html#boost_optional.relnotes.boost_release_1_66">Boost
       Release 1.66</a>
     </h4>
@@ -94,7 +109,7 @@
         </li>
 </ul></div>
 <h4>
-<a name="boost_optional.relnotes.h4"></a>
+<a name="boost_optional.relnotes.h5"></a>
       <span class="phrase"><a name="boost_optional.relnotes.boost_release_1_63"></a></span><a class="link" href="relnotes.html#boost_optional.relnotes.boost_release_1_63">Boost
       Release 1.63</a>
     </h4>
@@ -118,7 +133,7 @@
         </li>
 </ul></div>
 <h4>
-<a name="boost_optional.relnotes.h5"></a>
+<a name="boost_optional.relnotes.h6"></a>
       <span class="phrase"><a name="boost_optional.relnotes.boost_release_1_62"></a></span><a class="link" href="relnotes.html#boost_optional.relnotes.boost_release_1_62">Boost
       Release 1.62</a>
     </h4>
@@ -126,7 +141,7 @@
           Fixed <a href="https://svn.boost.org/trac/boost/ticket/12179" target="_top">Trac #12179</a>.
         </li></ul></div>
 <h4>
-<a name="boost_optional.relnotes.h6"></a>
+<a name="boost_optional.relnotes.h7"></a>
       <span class="phrase"><a name="boost_optional.relnotes.boost_release_1_61"></a></span><a class="link" href="relnotes.html#boost_optional.relnotes.boost_release_1_61">Boost
       Release 1.61</a>
     </h4>
@@ -169,7 +184,7 @@
         </li>
 </ul></div>
 <h4>
-<a name="boost_optional.relnotes.h7"></a>
+<a name="boost_optional.relnotes.h8"></a>
       <span class="phrase"><a name="boost_optional.relnotes.boost_release_1_60"></a></span><a class="link" href="relnotes.html#boost_optional.relnotes.boost_release_1_60">Boost
       Release 1.60</a>
     </h4>
@@ -180,7 +195,7 @@
           #11203</a>.
         </li></ul></div>
 <h4>
-<a name="boost_optional.relnotes.h8"></a>
+<a name="boost_optional.relnotes.h9"></a>
       <span class="phrase"><a name="boost_optional.relnotes.boost_release_1_59"></a></span><a class="link" href="relnotes.html#boost_optional.relnotes.boost_release_1_59">Boost
       Release 1.59</a>
     </h4>
@@ -194,7 +209,7 @@
         </li>
 </ul></div>
 <h4>
-<a name="boost_optional.relnotes.h9"></a>
+<a name="boost_optional.relnotes.h10"></a>
       <span class="phrase"><a name="boost_optional.relnotes.boost_release_1_58"></a></span><a class="link" href="relnotes.html#boost_optional.relnotes.boost_release_1_58">Boost
       Release 1.58</a>
     </h4>
@@ -230,7 +245,7 @@
         </li>
 </ul></div>
 <h4>
-<a name="boost_optional.relnotes.h10"></a>
+<a name="boost_optional.relnotes.h11"></a>
       <span class="phrase"><a name="boost_optional.relnotes.boost_release_1_57"></a></span><a class="link" href="relnotes.html#boost_optional.relnotes.boost_release_1_57">Boost
       Release 1.57</a>
     </h4>
@@ -240,7 +255,7 @@
           to fix C++03 compile error on <code class="computeroutput"><span class="identifier">logic_error</span><span class="special">(</span><span class="string">"..."</span><span class="special">)</span></code>"</em></span>.
         </li></ul></div>
 <h4>
-<a name="boost_optional.relnotes.h11"></a>
+<a name="boost_optional.relnotes.h12"></a>
       <span class="phrase"><a name="boost_optional.relnotes.boost_release_1_56"></a></span><a class="link" href="relnotes.html#boost_optional.relnotes.boost_release_1_56">Boost
       Release 1.56</a>
     </h4>

doc/html/index.html

@@ -145,7 +145,7 @@
 </div>
 </div>
 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
-<td align="left"><p><small>Last revised: November 08, 2018 at 17:44:53 GMT</small></p></td>
+<td align="left"><p><small>Last revised: December 19, 2019 at 23:27:43 GMT</small></p></td>
 <td align="right"><div class="copyright-footer"></div></td>
 </tr></table>
 <hr>

include/boost/none.hpp

@@ -13,6 +13,7 @@
 #ifndef BOOST_NONE_17SEP2003_HPP
 #define BOOST_NONE_17SEP2003_HPP
 
+#include "boost/config.hpp"
 #include "boost/none_t.hpp"
 
 // NOTE: Borland users have to include this header outside any precompiled headers
@@ -23,7 +24,7 @@ namespace boost {
 
 #ifdef BOOST_OPTIONAL_USE_OLD_DEFINITION_OF_NONE
 
-none_t const none = (static_cast<none_t>(0)) ;
+BOOST_INLINE_VARIABLE none_t const none = (static_cast<none_t>(0)) ;
 
 #elif defined BOOST_OPTIONAL_USE_SINGLETON_DEFINITION_OF_NONE
 
@@ -35,7 +36,7 @@ namespace detail { namespace optional_detail {
   {
     static const T instance;
   };
-  
+
   template <typename T>
   const T none_instance<T>::instance = T(); // global, but because 'tis a template, no cpp file required
 
@@ -49,7 +50,7 @@ namespace {
 
 #else
 
-const none_t none ((none_t::init_tag()));
+BOOST_INLINE_VARIABLE const none_t none ((none_t::init_tag()));
 
 #endif // older definitions
 

include/boost/optional/optional.hpp

@@ -777,7 +777,7 @@ class optional_base : public optional_tag
 
 #include <boost/optional/detail/optional_trivially_copyable_base.hpp>
 
-// definition of metafunciton is_optional_val_init_candidate
+// definition of metafunction is_optional_val_init_candidate
 template <typename U>
 struct is_optional_related
   : boost::conditional< boost::is_base_of<optional_detail::optional_tag, BOOST_DEDUCED_TYPENAME boost::decay<U>::type>::value
@@ -813,9 +813,14 @@ struct is_optional_constructible : boost::true_type
 
 #endif // is_convertible condition
 
-template <typename T, typename U>
+template <typename T, typename U, bool = is_optional_related<U>::value>
 struct is_optional_val_init_candidate
-  : boost::conditional< !is_optional_related<U>::value && is_convertible_to_T_or_factory<T, U>::value
+  : boost::false_type
+{};
+
+template <typename T, typename U>
+struct is_optional_val_init_candidate<T, U, false>
+  : boost::conditional< is_convertible_to_T_or_factory<T, U>::value
                       , boost::true_type, boost::false_type>::type
 {};
 
@@ -967,7 +972,7 @@ class optional
     // Can throw if T::T(T&&) does
 
 #ifndef BOOST_OPTIONAL_DETAIL_NO_DEFAULTED_MOVE_FUNCTIONS
-    optional ( optional && rhs ) = default;
+    optional ( optional && ) = default;
 #else
     optional ( optional && rhs )
       BOOST_NOEXCEPT_IF(::boost::is_nothrow_move_constructible<T>::value)

test/Jamfile.v2

@@ -50,6 +50,7 @@ import testing ;
     [ run optional_test_member_T.cpp ]
     [ run optional_test_tc_base.cpp ]
     [ compile optional_test_sfinae_friendly_ctor.cpp ]
+    [ compile optional_test_path_assignment.cpp ]
     [ compile-fail optional_test_fail_const_swap.cpp ]
     [ compile-fail optional_test_ref_convert_assign_const_int_prevented.cpp ]
     [ compile-fail optional_test_fail1.cpp ]

test/optional_test_path_assignment.cpp

@@ -0,0 +1,69 @@
+// Copyright (C) 2019 Andrzej Krzemienski.
+//
+// Use, modification, and distribution is subject to the Boost Software
+// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+//
+// See http://www.boost.org/lib/optional for documentation.
+//
+// You are welcome to contact the author at:
+//  akrzemi1@gmail.com
+
+#include "boost/optional/optional.hpp"
+
+#ifdef __BORLANDC__
+#pragma hdrstop
+#endif
+
+template <typename, typename>
+struct void_t
+{
+  typedef void type;
+};
+
+
+template <typename T, typename = void>
+struct trait
+{
+};
+
+// the following trait emulates properties std::iterator_traits
+template <typename T>
+struct trait<T, BOOST_DEDUCED_TYPENAME void_t<BOOST_DEDUCED_TYPENAME T::value_type,
+                                              BOOST_DEDUCED_TYPENAME boost::enable_if<boost::is_constructible<T, T&> >::type
+                                             >::type>
+{
+  typedef BOOST_DEDUCED_TYPENAME T::value_type value_type;
+};
+
+// This class emulates the properties of std::filesystem::path
+struct Path
+{
+
+#if __cplusplus >= 201103
+    template <typename T, typename = BOOST_DEDUCED_TYPENAME trait<T>::value_type>
+        Path(T const&);
+#else
+  template <typename T>
+    Path(T const&, BOOST_DEDUCED_TYPENAME trait<T>::value_type* = 0);
+#endif
+
+};
+
+
+int main()
+{
+#ifndef BOOST_OPTIONAL_DETAIL_NO_IS_CONSTRUCTIBLE_TRAIT
+#ifndef BOOST_OPTIONAL_DETAIL_NO_SFINAE_FRIENDLY_CONSTRUCTORS
+
+    boost::optional<Path> optFs1;
+    boost::optional<Path> optFs2;
+
+    optFs1 = optFs2;
+
+    // the following still fails although it shouldn't
+    //BOOST_STATIC_ASSERT((std::is_copy_constructible<boost::optional<Path>>::value));
+
+#endif
+#endif
+}