Build support for gcc < 5.x

[rexut]

Implicit casts of QPointer<T>& in signal/slot connection

There are many compile errors on implicit casts of QPointer<T>& in signal/slot connection when building with GCC < 5.x. The following error happens when building with GCC 4.8.4:

... no matching function for call to ‘QObject::connect(QPointer<T>&, ...)’
... no matching function for call to ‘QObject::disconnect(QPointer<T>&, ...)’

It's apparently a compiler bug that fixed in GCC 5.x and later. However, working around it is not very costly, and GCC 4.8 is supposed to should be supported. Similar report in Qt Bug Database QTBUG-69512.

src/card/base/CardConnectionWorker.cpp (Click to expand)

/tmp/AusweisApp2/src/card/base/CardConnectionWorker.cpp: In constructor ‘governikus::CardConnectionWorker::CardConnectionWorker(governikus::Reader*)’:
/tmp/AusweisApp2/src/card/base/CardConnectionWorker.cpp:21:94: error: no matching function for call to ‘governikus::CardConnectionWorker::connect(QPointer&, void (governikus::Reader::*)(const QString&), governikus::CardConnectionWorker* const, void (governikus::CardConnectionWorker::*)(const QString&))’
  connect(mReader, &Reader::fireCardInserted, this, &CardConnectionWorker::onReaderInfoChanged);
                                                                                              ^
/tmp/AusweisApp2/src/card/base/CardConnectionWorker.cpp:21:94: note:   mismatched types ‘const typename QtPrivate::FunctionPointer::Object*’ and ‘QPointer’
  connect(mReader, &Reader::fireCardInserted, this, &CardConnectionWorker::onReaderInfoChanged);
                                                                                              ^

...

/tmp/AusweisApp2/src/card/base/CardConnectionWorker.cpp:22:93: error: no matching function for call to ‘governikus::CardConnectionWorker::connect(QPointer&, void (governikus::Reader::*)(const QString&), governikus::CardConnectionWorker* const, void (governikus::CardConnectionWorker::*)(const QString&))’
  connect(mReader, &Reader::fireCardRemoved, this, &CardConnectionWorker::onReaderInfoChanged);
                                                                                             ^
/tmp/AusweisApp2/src/card/base/CardConnectionWorker.cpp:22:93: note:   mismatched types ‘const typename QtPrivate::FunctionPointer::Object*’ and ‘QPointer’
  connect(mReader, &Reader::fireCardRemoved, this, &CardConnectionWorker::onReaderInfoChanged);
                                                                                             ^

...

/tmp/AusweisApp2/src/card/base/CardConnectionWorker.cpp:23:105: error: no matching function for call to ‘governikus::CardConnectionWorker::connect(QPointer&, void (governikus::Reader::*)(const QString&), governikus::CardConnectionWorker* const, void (governikus::CardConnectionWorker::*)(const QString&))’
  connect(mReader, &Reader::fireCardRetryCounterChanged, this, &CardConnectionWorker::onReaderInfoChanged);
                                                                                                         ^
/tmp/AusweisApp2/src/card/base/CardConnectionWorker.cpp:23:105: note:   mismatched types ‘const typename QtPrivate::FunctionPointer::Object*’ and ‘QPointer’
  connect(mReader, &Reader::fireCardRetryCounterChanged, this, &CardConnectionWorker::onReaderInfoChanged);
                                                                                                         ^
At global scope:
cc1plus: warning: unrecognized command line option "-Wno-gnu-zero-variadic-macro-arguments" [enabled by default]

src/qml/HistoryModel.cpp (Click to expand)

/tmp/AusweisApp2/src/qml/HistoryModel.cpp: In constructor ‘governikus::HistoryModel::HistoryModel(governikus::HistorySettings*, QObject*)’:
/tmp/AusweisApp2/src/qml/HistoryModel.cpp:122:115: error: no matching function for call to ‘governikus::HistoryModel::connect(QPointer&, void (governikus::HistorySettings::*)(), governikus::HistoryModel* const, void (governikus::HistoryModel::*)())’
  connect(mHistorySettings, &HistorySettings::fireHistoryInfosChanged, this, &HistoryModel::onHistoryEntriesChanged);
                                                                                                                   ^
/tmp/AusweisApp2/src/qml/HistoryModel.cpp:122:115: note:   mismatched types ‘const typename QtPrivate::FunctionPointer::Object*’ and ‘QPointer’
  connect(mHistorySettings, &HistorySettings::fireHistoryInfosChanged, this, &HistoryModel::onHistoryEntriesChanged);
                                                                                                                   ^

...

/tmp/AusweisApp2/src/qml/HistoryModel.cpp:123:105: error: no matching function for call to ‘governikus::HistoryModel::connect(QPointer&, void (governikus::HistorySettings::*)(bool), governikus::HistoryModel* const, void (governikus::HistoryModel::*)(bool))’
  connect(mHistorySettings, &HistorySettings::fireEnabledChanged, this, &HistoryModel::fireEnabledChanged);
                                                                                                         ^
/tmp/AusweisApp2/src/qml/HistoryModel.cpp:123:105: note:   mismatched types ‘const typename QtPrivate::FunctionPointer::Object*’ and ‘QPointer’
  connect(mHistorySettings, &HistorySettings::fireEnabledChanged, this, &HistoryModel::fireEnabledChanged);
                                                                                                         ^

...

/tmp/AusweisApp2/src/qml/HistoryModel.cpp: In member function ‘virtual bool governikus::HistoryModel::removeRows(int, int, const QModelIndex&)’:
/tmp/AusweisApp2/src/qml/HistoryModel.cpp:369:118: error: no matching function for call to ‘governikus::HistoryModel::disconnect(QPointer&, void (governikus::HistorySettings::*)(), governikus::HistoryModel* const, void (governikus::HistoryModel::*)())’
  disconnect(mHistorySettings, &HistorySettings::fireHistoryInfosChanged, this, &HistoryModel::onHistoryEntriesChanged);
                                                                                                                      ^
/tmp/AusweisApp2/src/qml/HistoryModel.cpp:369:118: note:   mismatched types ‘const typename QtPrivate::FunctionPointer::Object*’ and ‘QPointer’
  disconnect(mHistorySettings, &HistorySettings::fireHistoryInfosChanged, this, &HistoryModel::onHistoryEntriesChanged);
                                                                                                                      ^

...

/tmp/AusweisApp2/src/qml/HistoryModel.cpp:371:115: error: no matching function for call to ‘governikus::HistoryModel::connect(QPointer&, void (governikus::HistorySettings::*)(), governikus::HistoryModel* const, void (governikus::HistoryModel::*)())’
  connect(mHistorySettings, &HistorySettings::fireHistoryInfosChanged, this, &HistoryModel::onHistoryEntriesChanged);
                                                                                                                   ^
/tmp/AusweisApp2/src/qml/HistoryModel.cpp:371:115: note:   mismatched types ‘const typename QtPrivate::FunctionPointer::Object*’ and ‘QPointer’
  connect(mHistorySettings, &HistorySettings::fireHistoryInfosChanged, this, &HistoryModel::onHistoryEntriesChanged);
                                                                                                                   ^
At global scope:
cc1plus: warning: unrecognized command line option "-Wno-gnu-zero-variadic-macro-arguments" [enabled by default]

src/widget/DiagnosisGui.cpp (Click to expand)

/tmp/AusweisApp2/src/widget/DiagnosisGui.cpp: In member function ‘void governikus::DiagnosisGui::activate()’:
/tmp/AusweisApp2/src/widget/DiagnosisGui.cpp:50:72: error: no matching function for call to ‘governikus::DiagnosisGui::connect(QPointer&, void (QDialog::*)(int), governikus::DiagnosisGui* const, void (governikus::DiagnosisGui::*)())’
  connect(mDialog, &QDialog::finished, this, &DiagnosisGui::fireFinished);
                                                                        ^
/tmp/AusweisApp2/src/widget/DiagnosisGui.cpp:50:72: note:   mismatched types ‘const typename QtPrivate::FunctionPointer::Object*’ and ‘QPointer’
  connect(mDialog, &QDialog::finished, this, &DiagnosisGui::fireFinished);
                                                                        ^
At global scope:
cc1plus: warning: unrecognized command line option "-Wno-gnu-zero-variadic-macro-arguments" [enabled by default]

src/widget/SetupAssistantGui.cpp (Click to expand)

/tmp/AusweisApp2/src/widget/SetupAssistantGui.cpp: In member function ‘void governikus::SetupAssistantGui::activate()’:
/tmp/AusweisApp2/src/widget/SetupAssistantGui.cpp:39:123: error: no matching function for call to ‘governikus::SetupAssistantGui::connect(QPointer&, void (governikus::SetupAssistantWizard::*)(), governikus::SetupAssistantGui* const, void (governikus::SetupAssistantGui::*)())’
   connect(mWizard, &SetupAssistantWizard::fireChangePinButtonClicked, this, &SetupAssistantGui::fireChangePinButtonClicked);
                                                                                                                           ^
/tmp/AusweisApp2/src/widget/SetupAssistantGui.cpp:39:123: note:   mismatched types ‘const typename QtPrivate::FunctionPointer::Object*’ and ‘QPointer’
   connect(mWizard, &SetupAssistantWizard::fireChangePinButtonClicked, this, &SetupAssistantGui::fireChangePinButtonClicked);
                                                                                                                           ^
At global scope:
cc1plus: warning: unrecognized command line option "-Wno-gnu-zero-variadic-macro-arguments" [enabled by default]

src/widget/step/StepChooseCardGui.cpp (Click to expand)

/tmp/AusweisApp2/src/widget/step/StepChooseCardGui.cpp: In constructor ‘governikus::StepChooseCardGui::StepChooseCardGui(const QSharedPointer&, governikus::AuthenticateStepsWidget*)’:
/tmp/AusweisApp2/src/widget/step/StepChooseCardGui.cpp:42:105: error: no matching function for call to ‘governikus::StepChooseCardGui::connect(QPointer&, void (governikus::ReaderDeviceGui::*)(), governikus::StepChooseCardGui* const, void (governikus::StepChooseCardGui::*)())’
  connect(mReaderDeviceGui, &ReaderDeviceGui::fireFinished, this, &StepChooseCardGui::onSubDialogFinished);
                                                                                                         ^
/tmp/AusweisApp2/src/widget/step/StepChooseCardGui.cpp:42:105: note:   mismatched types ‘const typename QtPrivate::FunctionPointer::Object*’ and ‘QPointer’
  connect(mReaderDeviceGui, &ReaderDeviceGui::fireFinished, this, &StepChooseCardGui::onSubDialogFinished);
                                                                                                         ^
At global scope:
cc1plus: warning: unrecognized command line option "-Wno-gnu-zero-variadic-macro-arguments" [enabled by default]

[CLAassistant]

All committers have signed the CLA.

[misery]

Thanks for your pull request!
I already merged the gcc stuff into our internal mainline branch. But what is the reason to use that gcc version?

By the way... we support gcc 4.9 and higher. But this change is tiny enough to accept it.

[rexut]

I already merged the gcc stuff into our internal mainline branch.

Thx

... But what is the reason to use that gcc version?

Some of the current Linux distributions with long-time support primarily only offer older GCC versions, for example CentOS and Red Hat Enterprise Linux 7 offer gcc 4.8.x (see: What gcc versions are available in Red Hat Enterprise Linux?), CentOS and RHEL 6 even only gcc 4.4.x. Both versions promise a lifetime beyond 2020, see: End-of-support schedule. Under these circumstances, it would not be possible to build the AusweisApp2 on these systems without additional changes, which is often not allowed in the Enterprise domain.

[misery]

Sorry for the delay! Certainly you perceived that Alpine fixed your report. So you could drop the work-around changeset. After that I will merge this PR. :-)

[rexut]

The Alpine bug report 9238 was successfully closed. I've revert this change in this pull-request #11. Now I'll change the title and description.