Merge branch 'dev' into python_custom_node_component

src/backend/langflow/graph/graph/base.py

@@ -60,7 +60,7 @@ class Graph:
         # the toolkit node
         self._build_node_params()
         # remove invalid nodes
-        self._remove_invalid_nodes()
+        self._validate_nodes()
 
     def _build_node_params(self) -> None:
         """Identifies and handles the LLM node within the graph."""
@@ -75,14 +75,13 @@ class Graph:
                 if isinstance(node, ToolkitVertex):
                     node.params["llm"] = llm_node
 
-    def _remove_invalid_nodes(self) -> None:
-        """Removes invalid nodes from the graph."""
-        self.nodes = [
-            node
-            for node in self.nodes
-            if self._validate_node(node)
-            or (len(self.nodes) == 1 and len(self.edges) == 0)
-        ]
+    def _validate_nodes(self) -> None:
+        """Check that all nodes have edges"""
+        for node in self.nodes:
+            if not self._validate_node(node):
+                raise ValueError(
+                    f"{node.vertex_type} is not connected to any other components"
+                )
 
     def _validate_node(self, node: Vertex) -> bool:
         """Validates a node."""