Fix segfault in Database editor (#2489)

execution_tests/active_by_default/.spinetoolbox/items/exporter/.export-manifest-e7cb0c670df62a5135b1dd6236afee47eaaad217.json

@@ -0,0 +1 @@
+{"data.csv": ["output\\base_scenario_e7cb0c670df62a5135b1dd6236afee47eaaad217\\data.csv"]}

execution_tests/active_by_default/.spinetoolbox/items/exporter/output/base_scenario_e7cb0c670df62a5135b1dd6236afee47eaaad217/.filter_id

@@ -0,0 +1 @@
+base_scenario - Test data

execution_tests/active_by_default/.spinetoolbox/items/exporter/output/base_scenario_e7cb0c670df62a5135b1dd6236afee47eaaad217/data.csv

@@ -0,0 +1 @@
+VisibleByDefault,visible

execution_tests/active_by_default/.spinetoolbox/local/project_local_data.json

@@ -0,0 +1,11 @@
+{
+    "items": {
+        "Test data": {
+            "url": {
+                "username": "",
+                "password": ""
+            }
+        },
+        "Exporter": {}
+    }
+}

execution_tests/active_by_default/.spinetoolbox/local/specification_local_data.json

@@ -0,0 +1,13 @@
+{
+    "Tool": {
+        "Run SpineOpt": {
+            "execution_settings": {}
+        },
+        "Load template": {
+            "execution_settings": {}
+        },
+        "Run SpineOpt detached": {
+            "execution_settings": {}
+        }
+    }
+}

spinetoolbox/mvcmodels/minimal_tree_model.py

@@ -147,7 +147,7 @@ def insert_children(self, position, children):
         """
         bad_types = [type(child) for child in children if not isinstance(child, TreeItem)]
         if bad_types:
-            raise TypeError(f"Can't insert children of type {bad_types} to an item of type {type(self)}")
+            raise TypeError(f"Can't insert children of type {bad_types} to an item of type {type(self).__name__}")
         if position < 0 or position > self.child_count():
             return False
         self._polish_children(children)

spinetoolbox/spine_db_editor/mvcmodels/multi_db_tree_item.py

@@ -201,7 +201,7 @@ def deep_take_db_map(self, db_map):
     def deep_merge(self, other):
         """Merges another item and all its descendants into this one."""
         if not isinstance(other, type(self)):
-            raise ValueError(f"Can't merge an instance of {type(other)} into a MultiDBTreeItem.")
+            raise ValueError(f"Can't merge an instance of {type(other).__name__} into a MultiDBTreeItem.")
         for db_map in other.db_maps:
             self.add_db_map_id(db_map, other.db_map_id(db_map))
         self._merge_children(other.children)

spinetoolbox/spine_db_editor/mvcmodels/multi_db_tree_model.py

@@ -31,6 +31,8 @@ def __init__(self, db_editor, db_mngr, *db_maps):
         self.db_editor = db_editor
         self.db_mngr = db_mngr
         self.db_maps = db_maps
+        self._invisible_root_item = TreeItem(self)
+        self.destroyed.connect(lambda obj=None: self._invisible_root_item.tear_down_recursively())
         self._root_item = None
 
     @property
@@ -52,12 +54,13 @@ def _header_labels(self):
 
     def build_tree(self):
         """Builds tree."""
-        self.beginResetModel()
-        self._invisible_root_item = TreeItem(self)
-        self.destroyed.connect(lambda obj=None: self._invisible_root_item.tear_down_recursively())
+        if self._invisible_root_item.has_children():
+            self.beginRemoveRows(QModelIndex(), 0, self.rowCount() - 1)
+            self._invisible_root_item = TreeItem(self)
+            self.destroyed.connect(lambda obj=None: self._invisible_root_item.tear_down_recursively())
+            self.endRemoveRows()
         self._root_item = self.root_item_type(self, dict.fromkeys(self.db_maps))
         self._invisible_root_item.append_children([self._root_item])
-        self.endResetModel()
 
     def columnCount(self, parent=QModelIndex()):
         return len(self._header_labels)