PR libstdc++/84159 fix appending strings to paths

The path::operator/=(const Source&) and path::append overloads were
still following the semantics of the Filesystem TS not C++17. Only
the path::operator/=(const path&) overload was correct.

This change adds more tests for path::operator/=(const path&) and adds
new tests to verify that the other append operations have equivalent
behaviour.

	PR libstdc++/84159
	* include/bits/fs_path.h (path::operator/=, path::append): Construct
	temporary path before calling _M_append.
	(path::_M_append): Change parameter to path and implement C++17
	semantics.
	* testsuite/27_io/filesystem/path/append/path.cc: Add helper function
	and more examples from the standard.
	* testsuite/27_io/filesystem/path/append/source.cc: New.
	* testsuite/27_io/filesystem/path/decompose/filename.cc: Add comment.
	* testsuite/27_io/filesystem/path/nonmember/append.cc: New.

From-SVN: r260255

1 files changed, 11 insertions, 14 deletions

diff --git a/libstdc++-v3/include/bits/fs_path.h b/libstdc++-v3/include/bits/fs_path.h
index 6703e91..53bf237 100644
--- a/libstdc++-v3/include/bits/fs_path.h
+++ b/libstdc++-v3/include/bits/fs_path.h
@@ -265,20 +265,17 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
     template <class _Source>
       _Path<_Source>&
       operator/=(_Source const& __source)
-      { return append(__source); }
+      { return _M_append(path(__source)); }
 
     template<typename _Source>
       _Path<_Source>&
       append(_Source const& __source)
-      {
-	return _M_append(_S_convert(_S_range_begin(__source),
-				    _S_range_end(__source)));
-      }
+      { return _M_append(path(__source)); }
 
     template<typename _InputIterator>
       _Path<_InputIterator, _InputIterator>&
       append(_InputIterator __first, _InputIterator __last)
-      { return _M_append(_S_convert(__first, __last)); }
+      { return _M_append(path(__first, __last)); }
 
     // concatenation
 
@@ -406,17 +403,17 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
 
     enum class _Split { _Stem, _Extension };
 
-    path& _M_append(string_type&& __str)
+    path&
+    _M_append(path __p)
     {
+      if (__p.is_absolute())
+	operator=(std::move(__p));
 #ifdef _GLIBCXX_FILESYSTEM_IS_WINDOWS
-      operator/=(path(std::move(__str)));
-#else
-      if (!_M_pathname.empty() && !_S_is_dir_sep(_M_pathname.back())
-	  && (__str.empty() || !_S_is_dir_sep(__str.front())))
-	_M_pathname += preferred_separator;
-      _M_pathname += __str;
-      _M_split_cmpts();
+      else if (__p.has_root_name() && __p.root_name() != root_name())
+	operator=(std::move(__p));
 #endif
+      else
+	operator/=(const_cast<const path&>(__p));
       return *this;
     }