QmlDesigner: Model should have at least one cell

* If all of the columns are deleted, all of the objects will be deleted
and a single column, with one empty row will be created.
* A bug is fixed for the cases that we have invalid selected column.

Task-number: QDS-11649
Fixes: QDS-11678
Change-Id: I8bdbd0176ad76dd761e98b5030cdc77379a8642b
Reviewed-by: Shrief Gabr <shrief.gabr@qt.io>
Reviewed-by: Miikka Heikkinen <miikka.heikkinen@qt.io>
Reviewed-by: Mahmoud Badri <mahmoud.badri@qt.io>

src/plugins/qmldesigner/components/collectioneditor/collectiondetailsmodel.cpp

@@ -219,11 +219,16 @@ bool CollectionDetailsModel::removeColumns(int column, int count, const QModelIn
     bool columnsRemoved = m_currentCollection.removeColumns(column, count);
     endRemoveColumns();
 
+    if (!columnCount(parent))
+        removeRows(0, rowCount(parent), parent);
+
     int nextColumn = column - 1;
     if (nextColumn < 0 && columnCount(parent) > 0)
         nextColumn = 0;
 
     selectColumn(nextColumn);
+
+    ensureSingleCell();
     return columnsRemoved;
 }
 
@@ -237,6 +242,7 @@ bool CollectionDetailsModel::removeRows(int row, int count, const QModelIndex &p
     bool rowsRemoved = m_currentCollection.removeElements(row, count);
     endRemoveRows();
 
+    ensureSingleCell();
     return rowsRemoved;
 }
 
@@ -317,8 +323,8 @@ bool CollectionDetailsModel::selectColumn(int section)
 
     const int columns = columnCount();
 
-    if (m_selectedColumn >= columns)
+    if (section >= columns)
-        return false;
+        section = columns - 1;
 
     selectRow(-1);
 
@@ -415,6 +421,7 @@ void CollectionDetailsModel::loadCollection(const ModelNode &sourceNode, const Q
             deselectAll();
             beginResetModel();
             switchToCollection(newReference);
+            ensureSingleCell();
             endResetModel();
         }
     } else {
@@ -583,6 +590,7 @@ void CollectionDetailsModel::loadJsonCollection(const QString &source, const QSt
     SourceFormat sourceFormat = jsonFileIsOk ? SourceFormat::Json : SourceFormat::Unknown;
     beginResetModel();
     m_currentCollection.resetDetails(getJsonHeaders(collectionNodes), elements, sourceFormat);
+    ensureSingleCell();
     endResetModel();
 }
 
@@ -635,9 +643,24 @@ void CollectionDetailsModel::loadCsvCollection(const QString &source,
     SourceFormat sourceFormat = csvFileIsOk ? SourceFormat::Csv : SourceFormat::Unknown;
     beginResetModel();
     m_currentCollection.resetDetails(headers, elements, sourceFormat);
+    ensureSingleCell();
     endResetModel();
 }
 
+void CollectionDetailsModel::ensureSingleCell()
+{
+    if (!m_currentCollection.isValid())
+        return;
+
+    if (!columnCount())
+        addColumn(0, "Column 1", "String");
+
+    if (!rowCount())
+        insertRow(0);
+
+    updateEmpty();
+}
+
 QVariant CollectionDetailsModel::variantFromString(const QString &value)
 {
     constexpr QStringView typesPattern{u"(?<boolean>^(?:true|false)$)|"

src/plugins/qmldesigner/components/collectioneditor/collectiondetailsmodel.h

@@ -81,6 +81,7 @@ private:
     void setCollectionName(const QString &newCollectionName);
     void loadJsonCollection(const QString &source, const QString &collection);
     void loadCsvCollection(const QString &source, const QString &collectionName);
+    void ensureSingleCell();
     QVariant variantFromString(const QString &value);
 
     QHash<CollectionReference, CollectionDetails> m_openedCollections;