Fixed a few exit crashes, added unit tests to cover them

pyqtgraph/GraphicsScene/GraphicsScene.py

@@ -84,8 +84,8 @@ class GraphicsScene(QtGui.QGraphicsScene):
             cls._addressCache[sip.unwrapinstance(sip.cast(obj, QtGui.QGraphicsItem))] = obj
             
             
-    def __init__(self, clickRadius=2, moveDistance=5):
-        QtGui.QGraphicsScene.__init__(self)
+    def __init__(self, clickRadius=2, moveDistance=5, parent=None):
+        QtGui.QGraphicsScene.__init__(self, parent)
         self.setClickRadius(clickRadius)
         self.setMoveDistance(moveDistance)
         self.exportDirectory = None

pyqtgraph/__init__.py

@@ -270,7 +270,12 @@ from .Qt import isQObjectAlive
 
 ## Attempts to work around exit crashes:
 import atexit
+_cleanupCalled = False
 def cleanup():
+    global _cleanupCalled
+    if _cleanupCalled:
+        return
+    
     if not getConfigOption('exitCleanup'):
         return
     
@@ -295,8 +300,22 @@ def cleanup():
                 s.addItem(o)
         except RuntimeError:  ## occurs if a python wrapper no longer has its underlying C++ object
             continue
+    _cleanupCalled = True
+
 atexit.register(cleanup)
 
+# Call cleanup when QApplication quits. This is necessary because sometimes
+# the QApplication will quit before the atexit callbacks are invoked.
+# Note: cannot connect this function until QApplication has been created, so
+# instead we have GraphicsView.__init__ call this for us.
+_cleanupConnected = False
+def _connectCleanup():
+    global _cleanupConnected
+    if _cleanupConnected:
+        return
+    QtGui.QApplication.instance().aboutToQuit.connect(cleanup)
+    _cleanupConnected = True
+
 
 ## Optional function for exiting immediately (with some manual teardown)
 def exit():

pyqtgraph/graphicsItems/HistogramLUTItem.py

@@ -49,7 +49,7 @@ class HistogramLUTItem(GraphicsWidget):
         self.setLayout(self.layout)
         self.layout.setContentsMargins(1,1,1,1)
         self.layout.setSpacing(0)
-        self.vb = ViewBox()
+        self.vb = ViewBox(parent=self)
         self.vb.setMaximumWidth(152)
         self.vb.setMinimumWidth(45)
         self.vb.setMouseEnabled(x=False, y=True)
@@ -59,7 +59,7 @@ class HistogramLUTItem(GraphicsWidget):
         self.region = LinearRegionItem([0, 1], LinearRegionItem.Horizontal)
         self.region.setZValue(1000)
         self.vb.addItem(self.region)
-        self.axis = AxisItem('left', linkView=self.vb, maxTickLength=-10)
+        self.axis = AxisItem('left', linkView=self.vb, maxTickLength=-10, parent=self)
         self.layout.addItem(self.axis, 0, 0)
         self.layout.addItem(self.vb, 0, 1)
         self.layout.addItem(self.gradient, 0, 2)

pyqtgraph/graphicsItems/PlotItem/PlotItem.py

@@ -145,7 +145,7 @@ class PlotItem(GraphicsWidget):
         self.layout.setVerticalSpacing(0)
         
         if viewBox is None:
-            viewBox = ViewBox()
+            viewBox = ViewBox(parent=self)
         self.vb = viewBox
         self.vb.sigStateChanged.connect(self.viewStateChanged)
         self.setMenuEnabled(enableMenu, enableMenu) ## en/disable plotitem and viewbox menus
@@ -168,14 +168,14 @@ class PlotItem(GraphicsWidget):
             axisItems = {}
         self.axes = {}
         for k, pos in (('top', (1,1)), ('bottom', (3,1)), ('left', (2,0)), ('right', (2,2))):
-            axis = axisItems.get(k, AxisItem(orientation=k))
+            axis = axisItems.get(k, AxisItem(orientation=k, parent=self))
             axis.linkToView(self.vb)
             self.axes[k] = {'item': axis, 'pos': pos}
             self.layout.addItem(axis, *pos)
             axis.setZValue(-1000)
             axis.setFlag(axis.ItemNegativeZStacksBehindParent)
         
-        self.titleLabel = LabelItem('', size='11pt')
+        self.titleLabel = LabelItem('', size='11pt', parent=self)
         self.layout.addItem(self.titleLabel, 0, 1)
         self.setTitle(None)  ## hide
         

pyqtgraph/graphicsItems/ViewBox/ViewBox.py

@@ -1696,6 +1696,8 @@ class ViewBox(GraphicsWidget):
     def forgetView(vid, name):
         if ViewBox is None:     ## can happen as python is shutting down
             return
+        if QtGui.QApplication.instance() is None:
+            return
         ## Called with ID and name of view (the view itself is no longer available)
         for v in list(ViewBox.AllViews.keys()):
             if id(v) == vid:

pyqtgraph/tests/test_exit_crash.py

@@ -0,0 +1,38 @@
+import os, sys, subprocess, tempfile
+import pyqtgraph as pg
+
+
+code = """
+import sys
+sys.path.insert(0, '{path}')
+import pyqtgraph as pg
+app = pg.mkQApp()
+w = pg.{classname}({args})
+"""
+
+
+def test_exit_crash():
+    # For each Widget subclass, run a simple python script that creates an 
+    # instance and then shuts down. The intent is to check for segmentation 
+    # faults when each script exits.
+    tmp = tempfile.mktemp(".py")
+    path = os.path.dirname(pg.__file__)
+
+    initArgs = {
+        'CheckTable': "[]",
+        'ProgressDialog': '"msg"',
+        'VerticalLabel': '"msg"',
+    }
+
+    for name in dir(pg):
+        obj = getattr(pg, name)
+        if not isinstance(obj, type) or not issubclass(obj, pg.QtGui.QWidget):
+            continue
+        
+        print name
+        argstr = initArgs.get(name, "")
+        open(tmp, 'w').write(code.format(path=path, classname=name, args=argstr))
+        proc = subprocess.Popen([sys.executable, tmp])
+        assert proc.wait() == 0
+
+    os.remove(tmp)

pyqtgraph/widgets/GraphicsView.py

@@ -71,6 +71,13 @@ class GraphicsView(QtGui.QGraphicsView):
         
         QtGui.QGraphicsView.__init__(self, parent)
         
+        # This connects a cleanup function to QApplication.aboutToQuit. It is
+        # called from here because we have no good way to react when the
+        # QApplication is created by the user.
+        # See pyqtgraph.__init__.py
+        from .. import _connectCleanup
+        _connectCleanup()
+        
         if useOpenGL is None:
             useOpenGL = getConfigOption('useOpenGL')
         
@@ -102,7 +109,8 @@ class GraphicsView(QtGui.QGraphicsView):
         self.currentItem = None
         self.clearMouse()
         self.updateMatrix()
-        self.sceneObj = GraphicsScene()
+        # GraphicsScene must have parent or expect crashes!
+        self.sceneObj = GraphicsScene(parent=self)
         self.setScene(self.sceneObj)
         
         ## Workaround for PySide crash
@@ -143,7 +151,6 @@ class GraphicsView(QtGui.QGraphicsView):
     
     def paintEvent(self, ev):
         self.scene().prepareForPaint()
-        #print "GV: paint", ev.rect()
         return QtGui.QGraphicsView.paintEvent(self, ev)
     
     def render(self, *args, **kwds):