From a1970104d0c4a1ea506dfd8e76f975d5cc88b33a Mon Sep 17 00:00:00 2001
From: Hugo Mercier <hugo.mercier@oslandia.com>
Date: Mon, 14 Jan 2019 14:53:38 +0100
Subject: [PATCH] Fix vertextool's geometry cache invalidation

This a forward port from d79c212e7ba1e5 in PR #8724

Another fix is added here (which will be backported to 3.4): layer'
signal connections must be destroyed when the cache for this layer is
cleared (otherwise I got an "assertion failed" in onCacheGeometryXXXX)
---
 src/app/vertextool/qgsvertextool.cpp | 19 ++++++++++++++++---
 src/app/vertextool/qgsvertextool.h   |  2 ++
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/src/app/vertextool/qgsvertextool.cpp b/src/app/vertextool/qgsvertextool.cpp
index 7f85350ccc4..a0e42c33018 100644
--- a/src/app/vertextool/qgsvertextool.cpp
+++ b/src/app/vertextool/qgsvertextool.cpp
@@ -980,14 +980,17 @@ void QgsVertexTool::keyPressEvent( QKeyEvent *e )
 
 QgsGeometry QgsVertexTool::cachedGeometry( const QgsVectorLayer *layer, QgsFeatureId fid )
 {
-  if ( !mCache.contains( layer ) )
+  const bool layerWasNotInCache = !mCache.contains( layer );
+  // insert if it was not in cache
+  QHash<QgsFeatureId, QgsGeometry> &layerCache = mCache[layer];
+  if ( layerWasNotInCache )
   {
     connect( layer, &QgsVectorLayer::geometryChanged, this, &QgsVertexTool::onCachedGeometryChanged );
     connect( layer, &QgsVectorLayer::featureDeleted, this, &QgsVertexTool::onCachedGeometryDeleted );
-    // TODO: also clear cache when layer is deleted
+    connect( layer, &QgsVectorLayer::willBeDeleted, this, &QgsVertexTool::clearGeometryCache );
+    connect( layer, &QgsVectorLayer::dataChanged, this, &QgsVertexTool::clearGeometryCache );
   }
 
-  QHash<QgsFeatureId, QgsGeometry> &layerCache = mCache[layer];
   if ( !layerCache.contains( fid ) )
   {
     QgsFeature f;
@@ -1003,6 +1006,16 @@ QgsGeometry QgsVertexTool::cachedGeometryForVertex( const Vertex &vertex )
   return cachedGeometry( vertex.layer, vertex.fid );
 }
 
+void QgsVertexTool::clearGeometryCache()
+{
+  const QgsVectorLayer *layer = qobject_cast<const QgsVectorLayer *>( sender() );
+  mCache.remove( layer );
+  disconnect( layer, &QgsVectorLayer::geometryChanged, this, &QgsVertexTool::onCachedGeometryChanged );
+  disconnect( layer, &QgsVectorLayer::featureDeleted, this, &QgsVertexTool::onCachedGeometryDeleted );
+  disconnect( layer, &QgsVectorLayer::willBeDeleted, this, &QgsVertexTool::clearGeometryCache );
+  disconnect( layer, &QgsVectorLayer::dataChanged, this, &QgsVertexTool::clearGeometryCache );
+}
+
 void QgsVertexTool::onCachedGeometryChanged( QgsFeatureId fid, const QgsGeometry &geom )
 {
   QgsVectorLayer *layer = qobject_cast<QgsVectorLayer *>( sender() );
diff --git a/src/app/vertextool/qgsvertextool.h b/src/app/vertextool/qgsvertextool.h
index e01334372a8..1ff394792c9 100644
--- a/src/app/vertextool/qgsvertextool.h
+++ b/src/app/vertextool/qgsvertextool.h
@@ -97,6 +97,8 @@ class APP_EXPORT QgsVertexTool : public QgsMapToolAdvancedDigitizing
 
     void onCachedGeometryDeleted( QgsFeatureId fid );
 
+    void clearGeometryCache();
+
     void showVertexEditor();  //#spellok
 
     void deleteVertexEditorSelection();