QMetaEnum::fromType always -1 in debugger

[Joel Bodenmann]

I am successfully using Q_ENUM together with QMetaEnum::fromType in my code. Everything works great and I can convert the enum strings to the actual enum values. However, as soon as I run the same code in the debugger, QMetaEnum::fromType always returns -1 instead of the actual enum value. It works great when I am executing the code outside of the debugger (but still in debug mode, not release mode).

Does anybody have any idea what causes this problem and more importantly: How to fix it?

I am using Qt 5.5.1 with MinGW 4.9.2 32-Bit and GDB 7.8 on Windows 10 64-Bit.

[kshegunov]

@Joel-Bodenmann

Does anybody have any idea what causes this problem and more importantly: How to fix it?

Would you please provide some code that reproduces the issue. For example, how are you calling QMetaEnum::fromType how your class has been set up (the relevant parts). Do you have either the Q_OBJECT or Q_GADGET macros and so on.

[Joel Bodenmann]

Okay, I will write up a minimal test case that allows to reproduce the issue. Might take a few hours until I get to it, though.
My class uses Q_OBJECT.

[kshegunov]

@Joel-Bodenmann

Okay, I will write up a minimal test case that allows to reproduce the issue.

Well, I suggest to start with a few lines of code pasted here in the forum, and then if we couldn't deduce the problem from that you could go about preparing a whole example, how about that?

[Joel Bodenmann]

Sure, whatever helps :)
This is the relevant code:

class LibraryItem : public QObject
{
    Q_OBJECT

public:
    enum Type {
        TypeComponent = 0,
        TypePackage
    };
    Q_ENUM(Type)

	...

    static LibraryItem* factory()
	{
		const char* typeString = "TypeComponent";
		int typeInt = QMetaEnum::fromType<LibraryItem::Type>().keyToValue(typeString);

		// typeInt is 0 when running the code outside of the debugger, -1 when running inside the debugger
	}

    ...
};

[kshegunov]

@Joel-Bodenmann
Okay, this is a curious thing. I'd try some debugging of the QMetaEnum in debug mode, to see what the problem might be; something like this:

QMetaEnum myEnum = MetaEnum::fromType<LibraryItem::Type>();
if (!myEnum.isValid())
    qDebug() << myEnum.name() << " is invalid with scope " << myEnum.scope();

for (qint32 i = 0, count = myEnum.keyCount(); i < count; i++)
    qDebug() << myEnum.key(i);

Try it out and see what is printed in the debug window.