Details
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Bug
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Resolution: Incomplete
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P1: Critical
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5.13.2
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Android
Description
Built with Clang Qt for Android 5.9.3 (armv7a ABI), our client's app works on the hardware.
Built with Clang Qt for Android 5.13.2 (arm64 ABI), our client's app crashes on the hardware, with the following (minimal) stack trace:
#00 QQmlBinding::slowWrite(QQmlPropertyData const &, QQmlPropertyData const &, QV4Value const &, bool, QFlags<QQmlPropertyData::WriteFlag>) #01 GenericBinding<0>::write(QV4::Value const &, bool, QFlags<QQmlPropertyData::WriteFlag>) ?? 0:0
The hardware is an Android tablet, allwinner quadcore a64 p1, Android 6.0.1 Marshmallow, API 23, ART 2.1.0, Android Runtime 0.9, kernel 3.10.65 armv8l.
I guess the stack trace is minimal because the stack frame information isn't available, since dynamically generated code won't have debug symbols associated with it?
I don't have a proper minimal repro, but this is roughly what the code looks like:
// Base.qml
import QtQuick 2.2
Item {
property alias signaller: timer
// in reality, this was an object connected to
// some hardware which signalled when appropriate.
Timer {
id: timer
signal statusChanged(string newStatus)
running: true
repeat: true
interval: 5000
property int triggerCount: 0
onTriggered: {
triggerCount++
if (triggerCount == 1) {
timer.statusChanged("Connecting")
} else if (triggerCount == 2) {
timer.statusChanged("Connected")
}
}
}
}
// Derived.qml
import QtQuick 2.2
Base {
id: derived
property string textValue
function resetState() {
textValue = "Resetting State"
state = signaller.status == "Connecting" ? "first" : "second"
}
states: [
State {
name: "first"
PropertyChanges {
target: derived
textValue: "In First State"
signaller.onStatusChanged: derived.resetState()
}
},
State {
name: "second"
PropertyChanges {
target: derived
textValue: "In Second State"
}
}
]
}
Note that if the line:
signaller.onStatusChanged: derived.resetState()
is removed or commented out, the crash no longer occurs.
I haven't tested other versions or other platforms, the problem may be Qt version rather than ABI specific...