feat: refactor graph vertex sorting (#2583)

* refactor: extract method from class to new func

* test: add new tests

* refactor: simplify funcs to improve readability

* refactor: extract new func from larger func

* refactor: remove recursion from func

* refactor: remove coupling with graph and vertex

* refactor: create adapter funcs to use new code

* refactor: add test for sorting up to vertex N with is_start=True

---------

Co-authored-by: Gabriel Luiz Freitas Almeida <gabriel@langflow.org>

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

@@ -14,7 +14,7 @@ from langflow.graph.edge.base import ContractEdge
 from langflow.graph.graph.constants import lazy_load_vertex_dict
 from langflow.graph.graph.runnable_vertices_manager import RunnableVerticesManager
 from langflow.graph.graph.state_manager import GraphStateManager
-from langflow.graph.graph.utils import find_start_component_id, process_flow
+from langflow.graph.graph.utils import find_start_component_id, process_flow, sort_up_to_vertex
 from langflow.graph.schema import InterfaceComponentTypes, RunOutputs
 from langflow.graph.vertex.base import Vertex, VertexStates
 from langflow.graph.vertex.types import InterfaceVertex, StateVertex
@@ -1197,74 +1197,6 @@ class Graph:
         edges_repr = "\n".join([f"{edge.source_id} --> {edge.target_id}" for edge in self.edges])
         return f"Graph:\nNodes: {vertex_ids}\nConnections:\n{edges_repr}"
 
-    def sort_up_to_vertex(self, vertex_id: str, is_start: bool = False) -> List[Vertex]:
-        """Cuts the graph up to a given vertex and sorts the resulting subgraph."""
-        # Initial setup
-        visited = set()  # To keep track of visited vertices
-        excluded = set()  # To keep track of vertices that should be excluded
-
-        def get_successors(vertex, recursive=True):
-            # Recursively get the successors of the current vertex
-            successors = vertex.successors
-            if not successors:
-                return []
-            successors_result = []
-            for successor in successors:
-                # Just return a list of successors
-                if recursive:
-                    next_successors = get_successors(successor)
-                    successors_result.extend(next_successors)
-                successors_result.append(successor)
-            return successors_result
-
-        try:
-            stop_or_start_vertex = self.get_vertex(vertex_id)
-            stack = [vertex_id]  # Use a list as a stack for DFS
-        except ValueError:
-            stop_or_start_vertex = self.get_root_of_group_node(vertex_id)
-            stack = [stop_or_start_vertex.id]
-            vertex_id = stop_or_start_vertex.id
-        stop_predecessors = [pre.id for pre in stop_or_start_vertex.predecessors]
-        # DFS to collect all vertices that can reach the specified vertex
-        while stack:
-            current_id = stack.pop()
-            if current_id not in visited and current_id not in excluded:
-                visited.add(current_id)
-                current_vertex = self.get_vertex(current_id)
-                # Assuming get_predecessors is a method that returns all vertices with edges to current_vertex
-                for predecessor in current_vertex.predecessors:
-                    stack.append(predecessor.id)
-
-                if current_id == vertex_id:
-                    # We should add to visited all the vertices that are successors of the current vertex
-                    # and their successors and so on
-                    # if the vertex is a start, it means we are starting from the beginning
-                    # and getting successors
-                    for successor in current_vertex.successors:
-                        if is_start:
-                            stack.append(successor.id)
-                        else:
-                            excluded.add(successor.id)
-                        all_successors = get_successors(successor, recursive=False)
-                        for successor in all_successors:
-                            if is_start:
-                                stack.append(successor.id)
-                            else:
-                                excluded.add(successor.id)
-                elif current_id not in stop_predecessors and is_start:
-                    # If the current vertex is not the target vertex, we should add all its successors
-                    # to the stack if they are not in visited
-
-                    # If we are starting from the beginning, we should add all successors
-                    for successor in current_vertex.successors:
-                        if successor.id not in visited:
-                            stack.append(successor.id)
-
-        # Filter the original graph's vertices and edges to keep only those in `visited`
-        vertices_to_keep = [self.get_vertex(vid) for vid in visited]
-
-        return vertices_to_keep
-
     def layered_topological_sort(
         self,
         vertices: List[Vertex],
@@ -1395,6 +1327,21 @@ class Graph:
                 max_index = max(max_index, index_map[successor.id])
         return max_index
 
+    def __to_dict(self) -> Dict[str, Dict[str, List[str]]]:
+        """Converts the graph to a dictionary."""
+        result: Dict = dict()
+        for vertex in self.vertices:
+            vertex_id = vertex.id
+            sucessors = [i.id for i in self.get_all_successors(vertex)]
+            predecessors = [i.id for i in self.get_predecessors(vertex)]
+            result |= {vertex_id: {"successors": sucessors, "predecessors": predecessors}}
+        return result
+
+    def __filter_vertices(self, vertex_id: str, is_start: bool = False):
+        dictionaryized_graph = self.__to_dict()
+        vertex_ids = sort_up_to_vertex(dictionaryized_graph, vertex_id, is_start)
+        return [self.get_vertex(vertex_id) for vertex_id in vertex_ids]
+
     def sort_vertices(
         self,
         stop_component_id: Optional[str] = None,
@@ -1404,9 +1351,11 @@ class Graph:
         self.mark_all_vertices("ACTIVE")
         if stop_component_id is not None:
             self.stop_vertex = stop_component_id
-            vertices = self.sort_up_to_vertex(stop_component_id)
+            vertices = self.__filter_vertices(stop_component_id)
+
         elif start_component_id:
-            vertices = self.sort_up_to_vertex(start_component_id, is_start=True)
+            vertices = self.__filter_vertices(start_component_id, is_start=True)
+
         else:
             vertices = self.vertices
             # without component_id we are probably running in the chat

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

@@ -1,6 +1,8 @@
+from typing import List, Dict
 import copy
 from collections import deque
 
+
 PRIORITY_LIST_OF_INPUTS = ["webhook", "chat"]
 
 
@@ -224,3 +226,49 @@ def get_updated_edges(base_flow, g_nodes, g_edges, group_node_id):
         if edge["target"] == group_node_id or edge["source"] == group_node_id:
             updated_edges.append(new_edge)
     return updated_edges
+
+
+def get_successors(graph: Dict[str, Dict[str, List[str]]], vertex_id: str) -> List[str]:
+    successors_result = []
+    stack = [vertex_id]
+    while stack:
+        current_id = stack.pop()
+        successors_result.append(current_id)
+        stack.extend(graph[current_id]["successors"])
+    return successors_result
+
+
+def sort_up_to_vertex(graph: Dict[str, Dict[str, List[str]]], vertex_id: str, is_start: bool = False) -> List[str]:
+    """Cuts the graph up to a given vertex and sorts the resulting subgraph."""
+    try:
+        stop_or_start_vertex = graph[vertex_id]
+    except KeyError:
+        raise ValueError(f"Vertex {vertex_id} not found into graph")
+
+    visited, excluded = set(), set()
+    stack = [vertex_id]
+    stop_predecessors = set(stop_or_start_vertex["predecessors"])
+
+    while stack:
+        current_id = stack.pop()
+        if current_id in visited or current_id in excluded:
+            continue
+
+        visited.add(current_id)
+        current_vertex = graph[current_id]
+
+        stack.extend(current_vertex["predecessors"])
+
+        if current_id == vertex_id or (current_id not in stop_predecessors and is_start):
+            for successor_id in current_vertex["successors"]:
+                if is_start:
+                    stack.append(successor_id)
+                else:
+                    excluded.add(successor_id)
+                for succ_id in get_successors(graph, successor_id):
+                    if is_start:
+                        stack.append(succ_id)
+                    else:
+                        excluded.add(succ_id)
+
+    return list(visited)

tests/unit/graph/graph/test_utils.py

@@ -0,0 +1,122 @@
+import pytest
+
+from langflow.graph.graph import utils
+
+
+@pytest.fixture
+def graph():
+    return {
+        "A": {"successors": ["B"], "predecessors": []},
+        "B": {"successors": ["D"], "predecessors": ["A", "C"]},
+        "C": {"successors": ["B", "I"], "predecessors": ["N"]},
+        "D": {"successors": ["E", "F"], "predecessors": ["B"]},
+        "E": {"successors": ["G"], "predecessors": ["D"]},
+        "F": {"successors": ["G", "H"], "predecessors": ["D"]},
+        "G": {"successors": [], "predecessors": ["E", "F"]},
+        "H": {"successors": [], "predecessors": ["F"]},
+        "I": {"successors": ["M"], "predecessors": ["C", "J"]},
+        "J": {"successors": ["I", "K"], "predecessors": ["N"]},
+        "K": {"successors": ["Q", "P", "O"], "predecessors": ["J", "L"]},
+        "L": {"successors": ["K"], "predecessors": []},
+        "M": {"successors": [], "predecessors": ["I"]},
+        "N": {"successors": ["C", "J"], "predecessors": []},
+        "O": {"successors": ["R"], "predecessors": ["K"]},
+        "P": {"successors": ["U"], "predecessors": ["K"]},
+        "Q": {"successors": ["V"], "predecessors": ["K"]},
+        "R": {"successors": ["S"], "predecessors": ["O"]},
+        "S": {"successors": ["T"], "predecessors": ["R"]},
+        "T": {"successors": [], "predecessors": ["S"]},
+        "U": {"successors": ["W"], "predecessors": ["P"]},
+        "V": {"successors": ["Y"], "predecessors": ["Q"]},
+        "W": {"successors": ["X"], "predecessors": ["U"]},
+        "X": {"successors": [], "predecessors": ["W"]},
+        "Y": {"successors": ["Z"], "predecessors": ["V"]},
+        "Z": {"successors": [], "predecessors": ["Y"]},
+    }
+
+
+def test_get_successors_a(graph):
+    vertex_id = "A"
+
+    result = utils.get_successors(graph, vertex_id)
+
+    assert set(result) == {"A", "B", "D", "E", "F", "H", "G"}
+
+
+def test_get_successors_z(graph):
+    vertex_id = "Z"
+
+    result = utils.get_successors(graph, vertex_id)
+
+    assert set(result) == {"Z"}
+
+
+def test_sort_up_to_vertex_n_is_start(graph):
+    vertex_id = "N"
+
+    result = utils.sort_up_to_vertex(graph, vertex_id, is_start=True)
+    # Result shoud be all the vertices
+    assert set(result) == set(graph.keys())
+
+
+def test_sort_up_to_vertex_z(graph):
+    vertex_id = "Z"
+
+    result = utils.sort_up_to_vertex(graph, vertex_id)
+
+    assert set(result) == {"L", "N", "J", "K", "Q", "V", "Y", "Z"}
+
+
+def test_sort_up_to_vertex_x(graph):
+    vertex_id = "X"
+
+    result = utils.sort_up_to_vertex(graph, vertex_id)
+
+    assert set(result) == {"L", "N", "J", "K", "P", "U", "W", "X"}
+
+
+def test_sort_up_to_vertex_t(graph):
+    vertex_id = "T"
+
+    result = utils.sort_up_to_vertex(graph, vertex_id)
+
+    assert set(result) == {"L", "N", "J", "K", "O", "R", "S", "T"}
+
+
+def test_sort_up_to_vertex_m(graph):
+    vertex_id = "M"
+
+    result = utils.sort_up_to_vertex(graph, vertex_id)
+
+    assert set(result) == {"N", "C", "J", "I", "M"}
+
+
+def test_sort_up_to_vertex_h(graph):
+    vertex_id = "H"
+
+    result = utils.sort_up_to_vertex(graph, vertex_id)
+
+    assert set(result) == {"N", "C", "A", "B", "D", "F", "H"}
+
+
+def test_sort_up_to_vertex_g(graph):
+    vertex_id = "G"
+
+    result = utils.sort_up_to_vertex(graph, vertex_id)
+
+    assert set(result) == {"N", "C", "A", "B", "D", "F", "E", "G"}
+
+
+def test_sort_up_to_vertex_a(graph):
+    vertex_id = "A"
+
+    result = utils.sort_up_to_vertex(graph, vertex_id)
+
+    assert set(result) == {"A"}
+
+
+def test_sort_up_to_vertex_invalid_vertex(graph):
+    vertex_id = "7"
+
+    with pytest.raises(ValueError):
+        utils.sort_up_to_vertex(graph, vertex_id)