onMapToolChanged can cause null pointer deref

Author: brendanashworth

ai_tracer.py

@@ -48,13 +48,13 @@ class ShiftClickState(Enum):
 # polygon geometries. It handles the drawing of rubber bands on the
 # map canvas and the capturing of clicks to build the geometry.
 class AIVectorizerTool(QgsMapToolCapture):
-    def __init__(self, plugin, current_mode):
+    def __init__(self, plugin):
         # Extend QgsMapToolCapture
         cadDockWidget = plugin.iface.cadDockWidget()
-        super(AIVectorizerTool, self).__init__(plugin.iface.mapCanvas(), cadDockWidget, current_mode)
+        super(AIVectorizerTool, self).__init__(plugin.iface.mapCanvas(), cadDockWidget, QgsMapToolCapture.CaptureNone)
 
         self.plugin = plugin
-        self.rb = self.initRubberBand(current_mode)
+        self.rb = self.initRubberBand()
 
         # Options
         self.num_completions = 50
@@ -84,13 +84,14 @@ def __init__(self, plugin, current_mode):
         self.snapIndicator = QgsSnapIndicator(plugin.iface.mapCanvas())
         self.snapper = plugin.iface.mapCanvas().snappingUtils()
 
-    def initRubberBand(self, mode):
-        if mode == QgsMapToolCapture.CaptureLine:
+    def initRubberBand(self):
+        if self.mode() == QgsMapToolCapture.CaptureLine:
             rb = QgsRubberBand(self.plugin.iface.mapCanvas(), QgsWkbTypes.LineGeometry)
-        elif mode == QgsMapToolCapture.CapturePolygon:
+        elif self.mode() == QgsMapToolCapture.CapturePolygon:
             rb = QgsRubberBand(self.plugin.iface.mapCanvas(), QgsWkbTypes.PolygonGeometry)
         else:
-            raise ValueError
+            # TODO not sure how we could get here
+            rb = QgsRubberBand(self.plugin.iface.mapCanvas(), QgsWkbTypes.PolygonGeometry)
 
         rb.setFillColor(self.digitizingFillColor())
         rb.setStrokeColor(self.digitizingStrokeColor())
@@ -223,17 +224,24 @@ def canvasReleaseEvent(self, e):
             finally:
                 self.autocomplete_task = None
 
-        # Right click means we end
-        if e.button() == Qt.RightButton:
-            vlayer = self.plugin.iface.activeLayer()
-            if not isinstance(vlayer, QgsVectorLayer):
-                self.plugin.iface.messageBar().pushMessage(
-                    "Bunting Labs AI Vectorizer",
-                    "No active vector layer.",
-                    Qgis.Warning,
-                    duration=15)
-                return
+        vlayer = self.plugin.iface.activeLayer()
+        if not isinstance(vlayer, QgsVectorLayer):
+            self.plugin.iface.messageBar().pushMessage(
+                "Bunting Labs AI Vectorizer",
+                "No active vector layer.",
+                Qgis.Warning,
+                duration=15)
+            return
+        elif vlayer.wkbType() not in [QgsWkbTypes.LineString, QgsWkbTypes.MultiLineString,
+                                    QgsWkbTypes.Polygon, QgsWkbTypes.MultiPolygon]:
+            self.plugin.iface.messageBar().pushMessage(
+                "Bunting Labs AI Vectorizer",
+                "Unsupported vector layer type for AI autocomplete.",
+                Qgis.Warning,
+                duration=15)
+            return
 
+        if e.button() == Qt.RightButton:
             # Will be converted to the relevant geometry
             curve = self.captureCurve()
 
@@ -287,7 +295,6 @@ def canvasReleaseEvent(self, e):
             if len(self.vertices) >= 2 and not (e.modifiers() & Qt.ShiftModifier) and not wasDoubleClick:
                 root = QgsProject.instance().layerTreeRoot()
                 rlayers = [node.layer() for node in root.children() if isinstance(node, QgsLayerTreeLayer) and isinstance(node.layer(), QgsRasterLayer) and node.itemVisibilityChecked()]
-                vlayer = self.plugin.iface.activeLayer()
 
                 project_crs = QgsProject.instance().crs()
 
@@ -308,4 +315,5 @@ def canvasReleaseEvent(self, e):
     def deactivate(self):
         self.rb.reset()
 
-        self.scissors_icon.hide()
+        self.scissors_icon.hide()
+        self.plugin.action.setChecked(False)

plugin.py

@@ -42,8 +42,9 @@ def __init__(self, iface):
         # Set by the text box in save settings
         self.api_key_input = None
 
-        self.action = None
-        self.tracer = None
+        icon_path = os.path.join(os.path.dirname(__file__), "vectorizing_icon.png")
+        self.action = QAction(QIcon(icon_path), '<b>Vectorize with AI</b><p>Toggle editing on a vector layer then enable to autocomplete new geometries.</p>', None)
+        self.tracer = AIVectorizerTool(self)
 
         # Read the plugin version
         try:
@@ -58,9 +59,6 @@ def __init__(self, iface):
         self.settings_action = None
 
     def update_checkable(self):
-        if self.action is None:
-            return
-
         # Before onboarding, it's always checkable.
         if self.settings.value(SETTING_TOS, "") != "y" or self.settings.value(SETTING_API_TOKEN, "") == "":
             self.action.setEnabled(True)
@@ -82,35 +80,16 @@ def current_layer_change_event(self, layer):
 
         self.update_checkable()
 
-    def initTracer(self):
-        self.tracer = None
-
-        # see what type of layer we are vectorizing
-        vlayer = self.iface.activeLayer()
-        if isinstance(vlayer, QgsVectorLayer):
-            if vlayer.wkbType() in [QgsWkbTypes.LineString, QgsWkbTypes.MultiLineString]:
-                self.tracer = AIVectorizerTool(self, QgsMapToolCapture.CaptureLine)
-            elif vlayer.wkbType() in [QgsWkbTypes.Polygon, QgsWkbTypes.MultiPolygon]:
-                self.tracer = AIVectorizerTool(self, QgsMapToolCapture.CapturePolygon)
-            else:
-                self.iface.messageBar().pushMessage(
-                    "Bunting Labs AI Vectorizer",
-                    "Unsupported vector layer type for AI autocomplete.",
-                    Qgis.Warning,
-                    duration=15)
-
     def initGui(self):
         # Initialize the plugin GUI
-        icon_path = os.path.join(os.path.dirname(__file__), "vectorizing_icon.png")
 
-        self.action = QAction(QIcon(icon_path), '<b>Vectorize with AI</b><p>Toggle editing on a vector layer then enable to autocomplete new geometries.</p>', self.iface.mainWindow())
+        # Because we don't pass iface.mainWindow() to the QAction constructor in __init__
+        self.iface.mainWindow().addAction(self.action)
+
         self.action.setCheckable(True)
         self.action.triggered.connect(self.toolbarClick)
         self.iface.addToolBarIcon(self.action)
 
-        # Uncheck ourselves if they change tools
-        self.iface.mapCanvas().mapToolSet.connect(self.onMapToolChanged)
-
         # Trigger a current layer change event to get the right action
         self.current_layer_change_event(self.iface.activeLayer())
 
@@ -508,17 +487,6 @@ def unload(self):
 
         self.iface.removeToolBarIcon(self.action)
 
-    def onMapToolChanged(self, newTool, _):
-        if not isinstance(newTool, AIVectorizerTool):
-            self.deactivate()
-
-    def deactivate(self):
-        if isinstance(self.tracer, AIVectorizerTool):
-            self.tracer.deactivate()
-
-        self.action.setChecked(False)
-        self.tracer = None
-
     def toolbarClick(self):
         if self.action.isChecked():
             # Depending on how many settings someone has already set,
@@ -532,7 +500,6 @@ def toolbarClick(self):
                 self.openEmailDialog()
                 return
 
-            self.initTracer()
             self.iface.mapCanvas().setMapTool(self.tracer)
 
             self.action.setChecked(True)