[Bug libstdc++/102499] New: Noexcept not matching fgor std::filesystem::path. Compilation fails for clang

[Bug libstdc++/102499] New: Noexcept not matching fgor std::filesystem::path. Compilation fails for clang

[unlvsur at live dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102499

            Bug ID: 102499
           Summary: Noexcept not matching fgor std::filesystem::path.
                    Compilation fails for clang
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: unlvsur at live dot com
  Target Milestone: ---

cqwrteur@BU-Precision-Tower-5810:~/fast_io_cleanup/fast_io/examples/0011.qt$
clang++ -o qstring qstring.cc -Ofast -std=c++20 -s -flto -march=native
-fuse-ld=lld -I../../include -I/home/cqwrteur/qt5_build/qtbase/include -fPIE
In file included from qstring.cc:2:
In file included from ../../include/fast_io_driver/qt.h:5:
In file included from /home/cqwrteur/qt5_build/qtbase/include/QtCore/QFile:1:
In file included from /home/cqwrteur/qt5_build/qtbase/include/QtCore/qfile.h:1:
In file included from
/home/cqwrteur/qt5_build/qtbase/include/QtCore/../../../../qt5/qtbase/src/corelib/io/qfile.h:49:
In file included from
/usr/local/bin/../lib/gcc/x86_64-pc-linux-gnu/12.0.0/../../../../include/c++/12.0.0/filesystem:45:
/usr/local/bin/../lib/gcc/x86_64-pc-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/fs_path.h:1278:9:
error: exception specification in declaration does not match previous
declaration
  path::begin() const noexcept
        ^
/usr/local/bin/../lib/gcc/x86_64-pc-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/fs_path.h:492:14:
note: previous declaration is here
    iterator begin() const;
             ^
/usr/local/bin/../lib/gcc/x86_64-pc-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/fs_path.h:1286:9:
error: exception specification in declaration does not match previous
declaration
  path::end() const noexcept
        ^
/usr/local/bin/../lib/gcc/x86_64-pc-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/fs_path.h:493:14:
note: previous declaration is here
    iterator end() const;
             ^
2 errors generated.

[Bug libstdc++/102499] Noexcept not matching fgor std::filesystem::path. Compilation fails for clang

[unlvsur at live dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102499

--- Comment #1 from cqwrteur <unlvsur at live dot com> ---
noexcept is missing for begin() end(). That leads to problem that breaks clang.

I manually modify the header file and it works.

[Bug libstdc++/102499] Noexcept not matching for std::filesystem::path. Compilation fails for clang

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102499

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |redi at gcc dot gnu.org
             Status|UNCONFIRMED                 |ASSIGNED
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2021-09-27

[Bug libstdc++/102499] [12 Regression] Noexcept not matching for std::filesystem::path. Compilation fails for clang

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102499

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to work|                            |11.2.1
   Target Milestone|---                         |12.0
      Known to fail|                            |12.0
            Summary|Noexcept not matching for   |[12 Regression] Noexcept
                   |std::filesystem::path.      |not matching for
                   |Compilation fails for clang |std::filesystem::path.
                   |                            |Compilation fails for clang

[Bug libstdc++/102499] [12 Regression] Noexcept not matching for std::filesystem::path. Compilation fails for clang

[unlvsur at live dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102499

--- Comment #2 from cqwrteur <unlvsur at live dot com> ---
(In reply to cqwrteur from comment #1)
> noexcept is missing for begin() end(). That leads to problem that breaks
> clang.
> 
> I manually modify the header file and it works.

https://github.com/gcc-mirror/gcc/commit/42eff613d0c10f88dc7a44b14981876401a09981#diff-8cb9eb19d74e89b3acffd1a56c8bf7ca102f342b3b18134bba7729e343bdbce9

It looks like this cleanup patch has some issues. Probably need a new test file
for clang.

[Bug libstdc++/102499] [12 Regression] Noexcept not matching for std::filesystem::path. Compilation fails for clang

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102499

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
There are no tests using clang.

[Bug libstdc++/102499] [12 Regression] Noexcept not matching for std::filesystem::path. Compilation fails for clang

[unlvsur at live dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102499

--- Comment #4 from cqwrteur <unlvsur at live dot com> ---
(In reply to Jonathan Wakely from comment #3)
> There are no tests using clang.

okay. i will report if I still see any issues with clang after the patch.

[Bug libstdc++/102499] [12 Regression] Noexcept not matching for std::filesystem::path. Compilation fails for clang

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102499

--- Comment #5 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jonathan Wakely <redi@gcc.gnu.org>:

https://gcc.gnu.org/g:f2b7f56a15d9cbbd2f0db22e0e39c4dd161bab69

commit r12-3930-gf2b7f56a15d9cbbd2f0db22e0e39c4dd161bab69
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Mon Sep 27 22:07:12 2021 +0100

    libstdc++: Fix mismatched noexcept-specifiers in filesystem::path
[PR102499]

    Signed-off-by: Jonathan Wakely <jwakely@redhat.com>

    libstdc++-v3/ChangeLog:

            PR libstdc++/102499
            * include/bits/fs_path.h (path::begin, path::end): Add noexcept
            to declarations, to match definitions.

[Bug libstdc++/102499] [12 Regression] Noexcept not matching for std::filesystem::path. Compilation fails for clang

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102499

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
             Status|ASSIGNED                    |RESOLVED

--- Comment #6 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Fixed now, thanks for the report.

I do have local tests that I run with Clang, but they're not automated and not
part of the upstream testsuite, so I didn't notice this bug. My local clang
tests do pass again now.