[PyQt] sip_api_can_convert_to_type chokes on converting a Python list to a QLIst of enums.

[Gerard Vermeulen]

Hi,

I have the following sip declaration (left some irrelevant
ConvertToSubclass stuff out):

class QwtPickerMachine
{
%TypeHeaderCode
#include <qwt_picker_machine.h>
%End // %TypeHeaderCode

public:
    enum Command {
        Begin,
        Append,
        Move,
        End
    }; // enum Command

    virtual ~QwtPickerMachine();
    virtual QList<QwtPickerMachine::Command> transition(const
QwtEventPattern&, const QEvent*) = 0;
    void reset();
    int state() const;
    void setState(int);
protected:
    QwtPickerMachine();
..
}

And a Python demo program where QwtPicker::transition() is overridden:

class PickerMachine(QwtPickerMachine):
  
    def __init__(self, *args):
        QwtPickerMachine.__init__(self, *args)

    # __init__()
  
    def transition(self, eventPattern,  e):
        commands = []
        print commands
        # handle the mouse events
        if e.type() == QEvent.MouseButtonPress:
            if eventPattern.mouseMatch(QwtEventPattern.MouseSelect1, e):
                if self.state() == 0:
                    commands.append(QwtPickerMachine.Begin)
                    commands.append(QwtPickerMachine.Append)
                    self.setState(1)
        elif e.type() == QEvent.MouseMove:
            if self.state != 0:
                commands.append(Qwt.QwtPickerMachine.Append)
        elif e.type() == QEvent.MouseButtonRelease:
            commands.append(QwtPickerMachine.End)
            self.setState(0)
        # handling of the keyboard events is left as an excercise
        print commands
        return commands # "return []" works.
        return []

    # transition()
      
# class PickerMachine()        

And a modified siplib.c where

    printf("td_flags: %d; td_sipTypeName: %s\n", td->td_flags,
sipTypeName(td));

is added before the assert statement in sip_api_can_convert_to_type().

My demo program fails in when siplib has to handle the list that is
returned by PickerMachine.transition():

 1. QList<QwtPickerMachine::Command>
sipQwtPickerMachine::transition(const QwtEventPattern&,const QEvent *)
(this=0x00f0bcd0)
 2. []
 3. meth_QwtEventPattern_mouseMatch()
 4. td_flags: 16; td_sipTypeName: QMouseEvent
 5. meth_QwtPickerMachine_state()
 6. meth_QwtPickerMachine_setState()
 7. [0, 1]
 8. dealloc_QwtEventPattern()
 9. td_flags: 2; td_sipTypeName: QList<QwtPickerMachine::Command>
10. td_flags: 3; td_sipTypeName: QwtPickerMachine::Command
11. python: siplib.c:7505: sip_api_can_convert_to_type: Assertion
`(((td)->td_flags & 0x0007) == 0x0000) || (((td)->td_flags & 0x0007) ==
0x0002)' failed.
12. Aborted

where line 2 and 7 are written by the print statements in the Python
code above, line 4, 9, and 10 by the printf added to
sip_api_can_convert_to_type() and the other lines by the sip tracing
mechanism.

Best regards -- Gerard