[PyQt] PyQt5 5.7.1 QAbstractTableModel.layoutChanged regression

[Ales Erjavec]

Hi,

There appears to be a regression in PyQt5 5.7.1 w.r.t
QAbstractTableModel subclasses' ability to emit
layoutAboutToBeChanged/layoutChanged signals. They are silently
dropped and never delivered to any observer (i.e connected views).

The following example fails with an assertion error:

#######

from PyQt5.QtCore import QAbstractTableModel, QModelIndex, Qt
from PyQt5.QtTest import QSignalSpy

class TableModel(QAbstractTableModel):
    def rowCount(self, parent=QModelIndex()):
        return 1 if not parent.isValid() else 0
    def columnCount(self, parent=QModelIndex()):
        return 1 if not parent.isValid() else 0
    def data(self, index, role=Qt.DisplayRole):
        return None

t = TableModel()

t.layoutAboutToBeChanged.connect(lambda *a:
print("layoutAboutToBeChanged:", *a))
t.layoutChanged.connect(lambda *a: print("layoutChanged:", *a))

spy1 = QSignalSpy(t.layoutAboutToBeChanged)
spy2 = QSignalSpy(t.layoutChanged)

t.layoutAboutToBeChanged.emit()
t.layoutChanged.emit()

assert len(spy1)
assert len(spy2)

####

The same does work with PyQt5 5.7 (albeit with a warning from QSignalSpy)

Testing environment:
* OS: OSX 10.11.6
* Python: 3.5
* PyQt5: 5.7.1


Regards
Aleš Erjavec