From e8cb8fd5f01deb75eb6056e75ca3595cbb91de53 Mon Sep 17 00:00:00 2001
From: Peter Petrik <zilolv@gmail.com>
Date: Fri, 27 Oct 2023 12:07:21 +0200
Subject: [PATCH] fix #2879 photo crash on project switch

---
 app/attributes/attributecontroller.cpp | 73 ++++++++++++++------------
 app/qml/FormsStackManager.qml          | 14 ++++-
 app/qml/form/FormWrapper.qml           |  2 +-
 3 files changed, 52 insertions(+), 37 deletions(-)

diff --git a/app/attributes/attributecontroller.cpp b/app/attributes/attributecontroller.cpp
index e9344628f7..a4ef8b1764 100644
--- a/app/attributes/attributecontroller.cpp
+++ b/app/attributes/attributecontroller.cpp
@@ -359,59 +359,59 @@ void AttributeController::clearAll()
 void AttributeController::updateOnLayerChange()
 {
   clearAll();
+  QgsVectorLayer *layer = mFeatureLayerPair.layer();
+  if ( !layer )
+    return;
 
   // 1) DATA
-  QgsVectorLayer *layer = mFeatureLayerPair.layer();
-  if ( layer )
+  if ( layer->editFormConfig().layout() == Qgis::AttributeFormLayout::DragAndDrop )
   {
-    if ( layer->editFormConfig().layout() == Qgis::AttributeFormLayout::DragAndDrop )
+    QgsAttributeEditorContainer *root = layer->editFormConfig().invisibleRootContainer();
+    if ( root->columnCount() > 1 )
     {
-      QgsAttributeEditorContainer *root = layer->editFormConfig().invisibleRootContainer();
-      if ( root->columnCount() > 1 )
-      {
-        qDebug() << "root tab in manual config has multiple columns. not supported on mobile devices!";
-        root->setColumnCount( 1 );
-      }
+      qDebug() << "root tab in manual config has multiple columns. not supported on mobile devices!";
+      root->setColumnCount( 1 );
+    }
 
-      mHasTabs = allowTabs( root );
-      if ( mHasTabs )
+    mHasTabs = allowTabs( root );
+    if ( mHasTabs )
+    {
+      for ( QgsAttributeEditorElement *element : root->children() )
       {
-        for ( QgsAttributeEditorElement *element : root->children() )
+        if ( element->type() == Qgis::AttributeEditorType::Container )
         {
-          if ( element->type() == Qgis::AttributeEditorType::Container )
+          QgsAttributeEditorContainer *container = static_cast<QgsAttributeEditorContainer *>( element );
+          if ( container->columnCount() > 1 )
           {
-            QgsAttributeEditorContainer *container = static_cast<QgsAttributeEditorContainer *>( element );
-            if ( container->columnCount() > 1 )
-            {
-              qDebug() << "tab " << container->name() << " in manual config has multiple columns. not supported on mobile devices!";
-              container->setColumnCount( 1 );
-            }
-            createTab( container );
+            qDebug() << "tab " << container->name() << " in manual config has multiple columns. not supported on mobile devices!";
+            container->setColumnCount( 1 );
           }
+          createTab( container );
         }
       }
-      else
-      {
-        createTab( root );
-      }
     }
     else
     {
-      // Auto-Generated Layout
-      // We create fake root tab
-      QgsAttributeEditorContainer *tab = autoLayoutTabContainer();
-
-      // We need to look for relations and include them into form,
-      // in auto-generated layout they are not included in form config
-      discoverRelations( tab );
-
-      createTab( tab );
+      createTab( root );
     }
+  }
+  else
+  {
+    // Auto-Generated Layout
+    // We create fake root tab
+    QgsAttributeEditorContainer *tab = autoLayoutTabContainer();
 
-    if ( mRememberAttributesController )
-      mRememberAttributesController->storeLayerFields( layer );
+    // We need to look for relations and include them into form,
+    // in auto-generated layout they are not included in form config
+    discoverRelations( tab );
+
+    createTab( tab );
   }
 
+  if ( mRememberAttributesController )
+    mRememberAttributesController->storeLayerFields( layer );
+
+
   // 2) MODELS
   // for all other models, ownership is managed by Qt parent system
   AttributeTabModel *tabModel = new AttributeTabModel( mAttributeTabProxyModel.get(), this, mTabItems.size() );
@@ -462,6 +462,9 @@ void AttributeController::updateOnLayerChange()
 
 void AttributeController::updateOnFeatureChange()
 {
+  if (!mFeatureLayerPair.layer())
+    return;
+
   const QgsFeature feature = mFeatureLayerPair.feature();
 
   QMap<QUuid, std::shared_ptr<FormItem>>::iterator formItemsIterator = mFormItems.begin();
diff --git a/app/qml/FormsStackManager.qml b/app/qml/FormsStackManager.qml
index a76a58f123..dfbe36f9f2 100644
--- a/app/qml/FormsStackManager.qml
+++ b/app/qml/FormsStackManager.qml
@@ -62,7 +62,8 @@ Item {
   signal createLinkedFeatureRequested( var targetLayer, var parentPair )
   signal stakeoutFeature( var feature );
 
-  function openForm( pair, formState, panelState ) {
+  function openForm( pair, formState, panelState )
+  {
     if ( formsStack.depth === 0 )
     {
       let props = {
@@ -137,9 +138,20 @@ Item {
   }
 
   function reload() {
+    // For some reason some forms could be hanging around
+    // for some time with dangling layer pointers even after
+    // formsStack.clear() is called
+    // https://github.com/MerginMaps/input/issues/2879
+    for ( let i = 0; i <= formsStack.depth; i++ ) {
+      let form = formsStack.get( i )
+      form.featureLayerPair = __inputUtils.createFeatureLayerPair(null, __inputUtils.emptyGeometry(), __variablesManager )
+      form.project = null
+    }
+
     formsStack.clear() // removes all objects thanks to Qt parent system
   }
 
+
   function openLinkedFeature( linkedFeature ) {
     let props = {
       featureLayerPair: linkedFeature,
diff --git a/app/qml/form/FormWrapper.qml b/app/qml/form/FormWrapper.qml
index 26e5aed6b8..8ccec12306 100644
--- a/app/qml/form/FormWrapper.qml
+++ b/app/qml/form/FormWrapper.qml
@@ -34,7 +34,7 @@ Item {
   property real previewHeight
   property real panelHeight
 
-  property bool isReadOnly: featureLayerPair ? featureLayerPair.layer.readOnly : false
+  property bool isReadOnly: featureLayerPair && featureLayerPair.layer ? featureLayerPair.layer.readOnly : false
 
   signal closed()
   signal editGeometry( var pair )