Bug 812077 – dev-cpp/doctest-2.4.6 fails to compile (stringification.cpp:106:26: error: variable ‘bla2’ set but not > used [-Werror=unused-but-set-variable])

• Product: Gentoo Linux
• Status: RESOLVED FIXED

[Description Agostino Sarubbo 2021-09-08 06:42:28 UTC]

https://blogs.gentoo.org/ago/2020/07/04/gentoo-tinderbox/

Issue: dev-cpp/doctest-2.4.6 fails to compile.
Discovered on: amd64 (internal ref: ci)

NOTE:
This machine uses GCC-11: https://gcc.gnu.org/gcc-11/porting_to.html
If you think this is a GCC-11 related issue, please block bug 732706.

[Comment 1 Agostino Sarubbo 2021-09-08 06:42:31 UTC]

Created attachment 738112 [details]
build.log

build log and emerge --info

[Comment 2 Agostino Sarubbo 2021-09-08 06:42:32 UTC]

Possible context of error(s):

-- Could NOT find MPI_CXX (missing: MPI_CXX_LIB_NAMES MPI_CXX_HEADER_DIR MPI_CXX_WORKS) 
-- Could NOT find MPI (missing: MPI_CXX_FOUND CXX) 
/var/tmp/portage/dev-cpp/doctest-2.4.6/work/doctest-2.4.6/examples/all_features/stringification.cpp:106:26: error: variable ‘bla2’ set but not used [-Werror=unused-but-set-variable]

[Comment 3 Sam James 2021-09-08 06:45:09 UTC]

(In reply to Agostino Sarubbo from comment #2)
> Possible context of error(s):
> 
> -- Could NOT find MPI_CXX (missing: MPI_CXX_LIB_NAMES MPI_CXX_HEADER_DIR
> MPI_CXX_WORKS) 
> -- Could NOT find MPI (missing: MPI_CXX_FOUND CXX) 

I wonder why this is appearing all of a sudden.

> /var/tmp/portage/dev-cpp/doctest-2.4.6/work/doctest-2.4.6/examples/
> all_features/stringification.cpp:106:26: error: variable ‘bla2’ set but not
> used [-Werror=unused-but-set-variable]

[Comment 4 Petr Vaněk 2021-09-09 12:49:54 UTC]

This bug affects test phase only, where the issue is in one example (all tests and examples are built only if use-flag test is set). The issue is related with gcc-11, it is already know in upstream with proposed fixes [1,2]. I think we can use one of those patches to fix this.

[1] https://github.com/onqtam/doctest/pull/505
[2] https://github.com/onqtam/doctest/pull/520

(In reply to Sam James from comment #3)
> (In reply to Agostino Sarubbo from comment #2)
> > Possible context of error(s):
> > 
> > -- Could NOT find MPI_CXX (missing: MPI_CXX_LIB_NAMES MPI_CXX_HEADER_DIR
> > MPI_CXX_WORKS) 
> > -- Could NOT find MPI (missing: MPI_CXX_FOUND CXX) 
> 
> I wonder why this is appearing all of a sudden.

The mpi example is built conditionally only if MPI is found. There is no dependency set in the ebuild, therefore, it depends only if mpi is already installed in the system or not. Again, this is checked and compiled only if test use-flag is set but it does not affect installation.

[Comment 5 Larry the Git Cow 2021-09-18 03:04:57 UTC]

The bug has been closed via the following commit(s):

https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=c32b8a80a2f30e79dba6d53ec4da64285139a972

commit c32b8a80a2f30e79dba6d53ec4da64285139a972
Author:     Petr Vaněk <[e-mail]>
AuthorDate: 2021-09-13 07:17:51 +0000
Commit:     Sam James <[e-mail]>
CommitDate: 2021-09-18 03:04:47 +0000

    dev-cpp/doctest: fix gcc-11 related compilation error
    
    Apply patch in order to fix gcc-11 related compilation error. The patch
    follows proposed fixes to upstream [1,2].
    
    [1] https://github.com/onqtam/doctest/pull/505
    [2] https://github.com/onqtam/doctest/pull/520
    
    Closes: https://bugs.gentoo.org/812077
    Signed-off-by: Petr Vaněk <[e-mail]>
    Closes: https://github.com/gentoo/gentoo/pull/22280
    Signed-off-by: Sam James <[e-mail]>

 dev-cpp/doctest/doctest-2.4.6.ebuild               |  2 ++
 .../files/doctest-2.4.6-remove-unused-bla2.patch   | 23 ++++++++++++++++++++++
 2 files changed, 25 insertions(+)