[PATCH] PR libstdc++/86597 directory_entry observers should clear error_code

[Jonathan Wakely]

        PR libstdc++/86597
        * include/bits/fs_dir.h (directory_entry::_M_file_type(error_code&)):
        Clear error_code when cached type is used.
        * testsuite/27_io/filesystem/directory_entry/86597.cc: New test.

Committed to trunk, gcc-8 backport to follow.


commit 5849d364a0f81686e70b2a277bf2517fdd1bc968
Author: Jonathan Wakely <jwak...@redhat.com>
Date:   Wed Aug 8 13:46:06 2018 +0100

    PR libstdc++/86597 directory_entry observers should clear error_code
    
            PR libstdc++/86597
            * include/bits/fs_dir.h 
(directory_entry::_M_file_type(error_code&)):
            Clear error_code when cached type is used.
            * testsuite/27_io/filesystem/directory_entry/86597.cc: New test.

diff --git a/libstdc++-v3/include/bits/fs_dir.h 
b/libstdc++-v3/include/bits/fs_dir.h
index cf7a3c29376..9ee1cb66b61 100644
--- a/libstdc++-v3/include/bits/fs_dir.h
+++ b/libstdc++-v3/include/bits/fs_dir.h
@@ -318,7 +318,10 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
     _M_file_type(error_code& __ec) const noexcept
     {
       if (_M_type != file_type::none && _M_type != file_type::symlink)
-       return _M_type;
+       {
+         __ec.clear();
+         return _M_type;
+       }
       return status(__ec).type();
     }
 
diff --git a/libstdc++-v3/testsuite/27_io/filesystem/directory_entry/86597.cc 
b/libstdc++-v3/testsuite/27_io/filesystem/directory_entry/86597.cc
new file mode 100644
index 00000000000..3b2acbe5842
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/filesystem/directory_entry/86597.cc
@@ -0,0 +1,52 @@
+// Copyright (C) 2018 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-options "-std=gnu++17 -lstdc++fs" }
+// { dg-do run { target c++17 } }
+// { dg-require-filesystem-ts "" }
+
+#include <filesystem>
+#include <system_error>
+#include <testsuite_hooks.h>
+
+// PR libstdc++/86597
+
+void
+test01()
+{
+  const auto bad_ec = make_error_code(std::errc::address_in_use);
+  std::error_code ec;
+  std::filesystem::directory_entry ent(".");
+
+  ec = bad_ec;
+  VERIFY( ent.exists(ec) );
+  VERIFY( !ec );
+
+  ec = bad_ec;
+  VERIFY( ent.is_directory(ec) );
+  VERIFY( !ec );
+
+  ec = bad_ec;
+  VERIFY( !ent.is_regular_file(ec) );
+  VERIFY( !ec );
+}
+
+int
+main()
+{
+  test01();
+}