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Property - Default initialise temporary to avoid GCC7 warnings.

Merged Property - Default initialise temporary to avoid GCC7 warnings.
jonrob/Gaudi:GaudiKernel-Property-DefaultInitTemp into master
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Merged Christopher Rob Jones requested to merge jonrob/Gaudi:GaudiKernel-Property-DefaultInitTemp into master
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When building the LHCb stack using GCC7, and I seeing warnings like

[1493/1506] Building CXX object Rich/RichFutureDAQ/CMakeFiles/RichFutureDAQ.dir/src/RichRawBankDecoder.cpp.o
In file included from /usera/jonesc/LHCbCMake/Master/Gaudi/InstallArea/x86_64-centos7-gcc7-opt/include/GaudiKernel/TypeNameString.h:3:0,
                 from /usera/jonesc/LHCbCMake/Master/Gaudi/InstallArea/x86_64-centos7-gcc7-opt/include/GaudiKernel/ISvcManager.h:7,
                 from /usera/jonesc/LHCbCMake/Master/Gaudi/InstallArea/x86_64-centos7-gcc7-opt/include/GaudiKernel/ISvcLocator.h:6,
                 from /usera/jonesc/LHCbCMake/Master/Gaudi/InstallArea/x86_64-centos7-gcc7-opt/include/GaudiKernel/Algorithm.h:11,
                 from /usera/jonesc/LHCbCMake/Master/Gaudi/InstallArea/x86_64-centos7-gcc7-opt/include/GaudiAlg/GaudiAlgorithm.h:11,
                 from ../Rich/RichFutureKernel/RichFutureKernel/RichAlgBase.h:15,
                 from /var/clus/usera/jonesc/LHCbCMake/Master/LHCb/Rich/RichFutureDAQ/src/RichRawBankDecoder.h:16,
                 from /var/clus/usera/jonesc/LHCbCMake/Master/LHCb/Rich/RichFutureDAQ/src/RichRawBankDecoder.cpp:3:
/usera/jonesc/LHCbCMake/Master/Gaudi/InstallArea/x86_64-centos7-gcc7-opt/include/GaudiKernel/Property.h: In member function ‘StatusCode Gaudi::Property<TYPE, VERIFIER, HANDLERS>::fromString(const string&) [with TYPE = std::array<bool, 2>; VERIFIER = Gaudi::Details::Property::NullVerifier; HANDLERS = Gaudi::Details::Property::UpdateHandler]’:
/usera/jonesc/LHCbCMake/Master/Gaudi/InstallArea/x86_64-centos7-gcc7-opt/include/GaudiKernel/Property.h:468:7: warning: ‘*((void*)& tmp +1)’ may be used uninitialized in this function [-Wmaybe-uninitialized]
       m_value = std::forward<T>( v );
       ^~~~~~~
/usera/jonesc/LHCbCMake/Master/Gaudi/InstallArea/x86_64-centos7-gcc7-opt/include/GaudiKernel/Property.h:162:16: note: ‘*((void*)& tmp +1)’ was declared here
           TYPE tmp;
                ^~~
/usera/jonesc/LHCbCMake/Master/Gaudi/InstallArea/x86_64-centos7-gcc7-opt/include/GaudiKernel/Property.h:468:7: warning: ‘tmp’ may be used uninitialized in this function [-Wmaybe-uninitialized]
       m_value = std::forward<T>( v );
       ^~~~~~~
/usera/jonesc/LHCbCMake/Master/Gaudi/InstallArea/x86_64-centos7-gcc7-opt/include/GaudiKernel/Property.h:162:16: note: ‘tmp’ was declared here
           TYPE tmp;
                ^~~

The issue is the method toString creates a temporary which could (or GCC7 things it could) be used uninitialised. This MR simply adds a default initializer to the temporary.

Edited by Christopher Rob Jones

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Approved by
Hadrien Benjamin Grasland

Merged by avatar (Apr 23, 2025 3:58pm UTC)

Merge details

  • Changes merged into master with 72f52a3d (commits were squashed).
  • Deleted the source branch.

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  • Marco Clemencic resolved all discussions

    resolved all discussions

  • Marco Clemencic assigned to @clemenci

    assigned to @clemenci

  • Marco Clemencic changed milestone to %v29r0

    changed milestone to %v29r0

  • Marco Clemencic assigned to @hegner

    assigned to @hegner

  • C
    Marco Clemencic @clemenci ·
    Owner

    @hegner, please, squash it when you merge: there's a lot of spurious history.

    Alternatively (cleaner), @jonrob, you could rebase your branch.

  • Christopher Rob Jones
    Christopher Rob Jones @jonrob ·
    Author Contributor

    Rebasing is something I haven't fully got to grips with... I think I have rebased the branch to master in my local checkout

    git rebase master

    but when I try and push that to gitlab I get

    CernVM ~/LHCbCMake/Master/Gaudi > git push origin GaudiKernel-Property-DefaultInitTemp
To ssh://git@gitlab.cern.ch:7999/jonrob/Gaudi.git
 ! [rejected]        GaudiKernel-Property-DefaultInitTemp -> GaudiKernel-Property-DefaultInitTemp (non-fast-forward)
error: failed to push some refs to 'ssh://git@gitlab.cern.ch:7999/jonrob/Gaudi.git'
To prevent you from losing history, non-fast-forward updates were rejected
Merge the remote changes before pushing again.  See the 'Note about
fast-forwards' section of 'git push --help' for details.

    Presumably I am doing this wrong ?

  • Hadrien Benjamin Grasland
    Hadrien Benjamin Grasland @hgraslan ·
    Developer

    No, this is just git's way of telling you that rebasing is a fairly invasive operation that alters the commit history in a fashion that could confuse anyone who would have based work on your remote branch.

    Since there is no risk of this happening on this MR originating from your private fork, you can press the "I know what I'm doing" big red button by adding the --force switch (or, its shorthand, -f) to your git push command.

    Edited by Hadrien Benjamin Grasland
  • Christopher Rob Jones added 37 commits

    added 37 commits

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  • Christopher Rob Jones
    Christopher Rob Jones @jonrob ·
    Author Contributor

    Thanks. Big red button pushed...

  • Hadrien Benjamin Grasland approved this merge request

    approved this merge request

  • Charles Leggett merged

    merged

  • Charles Leggett mentioned in commit 72f52a3d

    mentioned in commit 72f52a3d

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