Details
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Bug
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Resolution: Done
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P1: Critical
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5.14.1, 5.15
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None
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Linux Ubuntu 18.04
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Linux/X11,
macOS
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c3662119b64e5afa3af737cfa0cb6b55f8c1bbb2 d97b13fc2ccd38dd6d38190722d2207bb26315b5 (qt/qtlocation/5.15)
Description
Tried to use Waveshare SIM7000 as NMEA device with serialnmea QML plugin. When connected and properly enabled, device is /dev/ttyUSB1
Minimal QML application with
PositionSource { name: "serialnmea" PluginParameter { name: "serialnmea.serial_port"; value: "/dev/ttyUSB1" }} (attached)
Verified that /dev/ttyUSB1 sends continuously proper nmea data, port ignores serial speed setting.
Application output:
QML debugging is enabled. Only use this in a safe environment. QObject::connect(QSerialPort, Unknown): invalid nullptr parameter qml: Position source serialnmea ready ^C
When run with QT_FATAL_WARNINGS=1 under QtCreator, the stack trace when aborted is
1 __GI_raise raise.c 51 0x7ffff5d47e97 2 __GI_abort abort.c 79 0x7ffff5d49801 3 qt_message_fatal qlogging.cpp 1894 0x7ffff672b123 4 QMessageLogger::warning qlogging.cpp 660 0x7ffff672b123 5 QObjectPrivate::connectImpl qobject.cpp 4991 0x7ffff695c2e9 6 QObject::connectImpl qobject.cpp 4970 0x7ffff695c4e8 7 QObjectPrivate::connect<void (QIODevice:: *)(), void (QIOPipePrivate:: *)()> qobject_p.h 462 0x7fffd0848dd6 8 QIOPipePrivate::QIOPipePrivate qiopipe.cpp 60 0x7fffd0848dd6 9 QIOPipe::QIOPipe qiopipe.cpp 131 0x7fffd0849054 10 IODeviceContainer::serial qgeopositioninfosourcefactory_serialnmea.cpp 79 0x7fffd0845147 11 NmeaSource::NmeaSource qgeopositioninfosourcefactory_serialnmea.cpp 164 0x7fffd0840cb3 12 QGeoPositionInfoSourceFactorySerialNmea::positionInfoSourceWithParameters qgeopositioninfosourcefactory_serialnmea.cpp 254 0x7fffd0841505 13 createSource_real qgeopositioninfosource.cpp 338 0x7fffd0c98cde 14 QGeoPositionInfoSource::createSource qgeopositioninfosource.cpp 411 0x7fffd0c999b0 15 QDeclarativePositionSource::tryAttach qdeclarativepositionsource.cpp 207 0x7fffd0f1475b 16 QDeclarativePositionSource::componentComplete qdeclarativepositionsource.cpp 861 0x7fffd0f14cd2 17 QQmlObjectCreator::finalize qqmlobjectcreator.cpp 1410 0x7ffff71426d2 18 QQmlComponentPrivate::complete qqmlcomponent.cpp 969 0x7ffff70d0917 19 QQmlComponentPrivate::completeCreate qqmlcomponent.cpp 1005 0x7ffff70d0a32 20 QQmlComponent::create qqmlcomponent.cpp 811 0x7ffff70d0429 21 QQmlApplicationEnginePrivate::finishLoad qqmlapplicationengine.cpp 134 0x7ffff7137f1c 22 QQmlApplicationEnginePrivate::startLoad qqmlapplicationengine.cpp 118 0x7ffff71380ae 23 QQmlApplicationEngine::load qqmlapplicationengine.cpp 264 0x7ffff71380dd 24 main main.cpp 17 0x5555555554db
Brief examination of the code reveals that the issue is within the constructor of the QIOPipe class: the QIOPipePrivate does QObjectPrivate::connect which internally accesses QIOPipePrivate::q_ptr but it is still null as the surrounding QObject constructor is not yet run.
The issue can reproduced by setting the port name to any valid unallocated tty, like /dev/ttyS1 on Linux or /dev/ttys000 on MacOs