fix: Preserve flows and components during project updates

src/backend/base/langflow/api/v1/projects.py

@@ -207,6 +207,14 @@ async def update_project(
     if not existing_project:
         raise HTTPException(status_code=404, detail="Project not found")
 
+    result = await session.exec(
+        select(Flow.id, Flow.is_component).where(Flow.folder_id == existing_project.id, Flow.user_id == current_user.id)
+    )
+    flows_and_components = result.all()
+
+    project.flows = [flow_id for flow_id, is_component in flows_and_components if not is_component]
+    project.components = [flow_id for flow_id, is_component in flows_and_components if is_component]
+
     try:
         # Track if MCP Composer needs to be started or stopped
         should_start_mcp_composer = False
@@ -261,7 +269,7 @@ async def update_project(
 
         flows_ids = (await session.exec(select(Flow.id).where(Flow.folder_id == existing_project.id))).all()
 
-        excluded_flows = list(set(flows_ids) - set(concat_project_components))
+        excluded_flows = list(set(flows_ids) - set(project.flows))
 
         my_collection_project = (await session.exec(select(Folder).where(Folder.name == DEFAULT_FOLDER_NAME))).first()
         if my_collection_project:

src/backend/tests/unit/api/v1/test_projects.py

@@ -169,3 +169,240 @@ async def test_create_and_read_project_cyrillic(client: AsyncClient, logged_in_h
 
     assert fetched["name"] == CYRILLIC_NAME
     assert fetched["description"] == CYRILLIC_DESC
+
+
+async def test_update_project_preserves_flows(client: AsyncClient, logged_in_headers):
+    """Test that renaming a project preserves all associated flows (regression test for flow loss bug)."""
+    # Create a project
+    project_payload = {
+        "name": "Project with Flows",
+        "description": "Testing flow preservation",
+        "flows_list": [],
+        "components_list": [],
+    }
+    create_resp = await client.post("api/v1/projects/", json=project_payload, headers=logged_in_headers)
+    assert create_resp.status_code == status.HTTP_201_CREATED
+    project = create_resp.json()
+    project_id = project["id"]
+
+    # Create flows in the project
+    flow1_payload = {
+        "name": "Test Flow 1",
+        "description": "First test flow",
+        "folder_id": project_id,
+        "data": {"nodes": [], "edges": []},
+        "is_component": False,
+    }
+    flow2_payload = {
+        "name": "Test Flow 2",
+        "description": "Second test flow",
+        "folder_id": project_id,
+        "data": {"nodes": [], "edges": []},
+        "is_component": False,
+    }
+
+    flow1_resp = await client.post("api/v1/flows/", json=flow1_payload, headers=logged_in_headers)
+    flow2_resp = await client.post("api/v1/flows/", json=flow2_payload, headers=logged_in_headers)
+    assert flow1_resp.status_code == status.HTTP_201_CREATED
+    assert flow2_resp.status_code == status.HTTP_201_CREATED
+
+    flow1_id = flow1_resp.json()["id"]
+    flow2_id = flow2_resp.json()["id"]
+
+    # Get project to verify flows are associated
+    get_resp = await client.get(f"api/v1/projects/{project_id}", headers=logged_in_headers)
+    assert get_resp.status_code == status.HTTP_200_OK
+    project_data = get_resp.json()
+
+    # Current behavior: all flows (including components) are in the flows field
+    flows_before = project_data.get("flows", [])
+    # Filter only actual flows (not components)
+    actual_flows_before = [f for f in flows_before if not f.get("is_component", False)]
+
+    assert len(actual_flows_before) == 2
+    flow_ids_before = [f["id"] for f in actual_flows_before]
+    assert str(flow1_id) in flow_ids_before
+    assert str(flow2_id) in flow_ids_before
+
+    # Update project name (the bug scenario)
+    update_payload = {"name": "Renamed Project with Flows", "description": "Testing flow preservation after rename"}
+    update_resp = await client.patch(f"api/v1/projects/{project_id}", json=update_payload, headers=logged_in_headers)
+    assert update_resp.status_code == status.HTTP_200_OK
+
+    # Verify project was renamed
+    updated_project = update_resp.json()
+    assert updated_project["name"] == "Renamed Project with Flows"
+
+    # Critical test: Verify flows are still associated after rename
+    get_after_resp = await client.get(f"api/v1/projects/{project_id}", headers=logged_in_headers)
+    assert get_after_resp.status_code == status.HTTP_200_OK
+    project_after = get_after_resp.json()
+
+    flows_after = project_after.get("flows", [])
+    actual_flows_after = [f for f in flows_after if not f.get("is_component", False)]
+
+    # This was the bug: flows were being lost after project rename
+    assert len(actual_flows_after) == 2, f"Expected 2 flows after rename, got {len(actual_flows_after)}. Flows lost!"
+
+    flow_ids_after = [f["id"] for f in actual_flows_after]
+    assert str(flow1_id) in flow_ids_after, "Flow 1 was lost after project rename!"
+    assert str(flow2_id) in flow_ids_after, "Flow 2 was lost after project rename!"
+
+    # Verify individual flows still exist and are accessible
+    flow1_get_resp = await client.get(f"api/v1/flows/{flow1_id}", headers=logged_in_headers)
+    flow2_get_resp = await client.get(f"api/v1/flows/{flow2_id}", headers=logged_in_headers)
+    assert flow1_get_resp.status_code == status.HTTP_200_OK
+    assert flow2_get_resp.status_code == status.HTTP_200_OK
+
+    # Verify flows still reference the correct project
+    flow1_data = flow1_get_resp.json()
+    flow2_data = flow2_get_resp.json()
+    assert str(flow1_data["folder_id"]) == str(project_id)
+    assert str(flow2_data["folder_id"]) == str(project_id)
+
+
+async def test_update_project_preserves_components(client: AsyncClient, logged_in_headers):
+    """Test that renaming a project preserves all associated components."""
+    # Create a project
+    project_payload = {
+        "name": "Project with Components",
+        "description": "Testing component preservation",
+        "flows_list": [],
+        "components_list": [],
+    }
+    create_resp = await client.post("api/v1/projects/", json=project_payload, headers=logged_in_headers)
+    assert create_resp.status_code == status.HTTP_201_CREATED
+    project = create_resp.json()
+    project_id = project["id"]
+
+    # Create components in the project
+    comp1_payload = {
+        "name": "Test Component 1",
+        "description": "First test component",
+        "folder_id": project_id,
+        "data": {"nodes": [], "edges": []},
+        "is_component": True,  # This makes it a component
+    }
+    comp2_payload = {
+        "name": "Test Component 2",
+        "description": "Second test component",
+        "folder_id": project_id,
+        "data": {"nodes": [], "edges": []},
+        "is_component": True,  # This makes it a component
+    }
+
+    comp1_resp = await client.post("api/v1/flows/", json=comp1_payload, headers=logged_in_headers)
+    comp2_resp = await client.post("api/v1/flows/", json=comp2_payload, headers=logged_in_headers)
+    assert comp1_resp.status_code == status.HTTP_201_CREATED
+    assert comp2_resp.status_code == status.HTTP_201_CREATED
+
+    comp1_id = comp1_resp.json()["id"]
+    comp2_id = comp2_resp.json()["id"]
+
+    # Get project to verify components are associated
+    get_resp = await client.get(f"api/v1/projects/{project_id}", headers=logged_in_headers)
+    assert get_resp.status_code == status.HTTP_200_OK
+    project_data = get_resp.json()
+
+    # Current behavior: all flows (including components) are in the flows field
+    flows_before = project_data.get("flows", [])
+    # Filter only components
+    components_before = [f for f in flows_before if f.get("is_component", False)]
+
+    assert len(components_before) == 2
+    component_ids_before = [c["id"] for c in components_before]
+    assert str(comp1_id) in component_ids_before
+    assert str(comp2_id) in component_ids_before
+
+    # Update project name
+    update_payload = {"name": "Renamed Project with Components"}
+    update_resp = await client.patch(f"api/v1/projects/{project_id}", json=update_payload, headers=logged_in_headers)
+    assert update_resp.status_code == status.HTTP_200_OK
+
+    # Verify components are still associated after rename
+    get_after_resp = await client.get(f"api/v1/projects/{project_id}", headers=logged_in_headers)
+    assert get_after_resp.status_code == status.HTTP_200_OK
+    project_after = get_after_resp.json()
+
+    flows_after = project_after.get("flows", [])
+    components_after = [f for f in flows_after if f.get("is_component", False)]
+
+    assert len(components_after) == 2, (
+        f"Expected 2 components after rename, got {len(components_after)}. Components lost!"
+    )
+
+    component_ids_after = [c["id"] for c in components_after]
+    assert str(comp1_id) in component_ids_after, "Component 1 was lost after project rename!"
+    assert str(comp2_id) in component_ids_after, "Component 2 was lost after project rename!"
+
+
+async def test_update_project_preserves_mixed_flows_and_components(client: AsyncClient, logged_in_headers):
+    """Test that renaming a project preserves both flows and components correctly."""
+    # Create a project
+    project_payload = {
+        "name": "Mixed Project",
+        "description": "Testing mixed flows and components preservation",
+        "flows_list": [],
+        "components_list": [],
+    }
+    create_resp = await client.post("api/v1/projects/", json=project_payload, headers=logged_in_headers)
+    assert create_resp.status_code == status.HTTP_201_CREATED
+    project = create_resp.json()
+    project_id = project["id"]
+
+    # Create flows and components
+    flow_payload = {
+        "name": "Regular Flow",
+        "description": "A regular flow",
+        "folder_id": project_id,
+        "data": {"nodes": [], "edges": []},
+        "is_component": False,
+    }
+    component_payload = {
+        "name": "Custom Component",
+        "description": "A custom component",
+        "folder_id": project_id,
+        "data": {"nodes": [], "edges": []},
+        "is_component": True,
+    }
+
+    flow_resp = await client.post("api/v1/flows/", json=flow_payload, headers=logged_in_headers)
+    comp_resp = await client.post("api/v1/flows/", json=component_payload, headers=logged_in_headers)
+    assert flow_resp.status_code == status.HTTP_201_CREATED
+    assert comp_resp.status_code == status.HTTP_201_CREATED
+
+    flow_id = flow_resp.json()["id"]
+    comp_id = comp_resp.json()["id"]
+
+    # Verify initial state
+    get_resp = await client.get(f"api/v1/projects/{project_id}", headers=logged_in_headers)
+    project_data = get_resp.json()
+
+    flows_before = project_data.get("flows", [])
+    actual_flows_before = [f for f in flows_before if not f.get("is_component", False)]
+    components_before = [f for f in flows_before if f.get("is_component", False)]
+
+    assert len(actual_flows_before) == 1
+    assert len(components_before) == 1
+
+    # Update project
+    update_payload = {"name": "Renamed Mixed Project"}
+    update_resp = await client.patch(f"api/v1/projects/{project_id}", json=update_payload, headers=logged_in_headers)
+    assert update_resp.status_code == status.HTTP_200_OK
+
+    # Verify both flows and components preserved
+    get_after_resp = await client.get(f"api/v1/projects/{project_id}", headers=logged_in_headers)
+    project_after = get_after_resp.json()
+
+    flows_after = project_after.get("flows", [])
+    actual_flows_after = [f for f in flows_after if not f.get("is_component", False)]
+    components_after = [f for f in flows_after if f.get("is_component", False)]
+
+    assert len(actual_flows_after) == 1, "Flow was lost after project rename!"
+    assert len(components_after) == 1, "Component was lost after project rename!"
+
+    flow_id_after = actual_flows_after[0]["id"]
+    comp_id_after = components_after[0]["id"]
+
+    assert str(flow_id) == flow_id_after
+    assert str(comp_id) == comp_id_after