test: add pyleak for task and event loop block detections (#8802)

* test: add pyleak for task and event loop block detections

* test: add pyleak for task and event loop block detections

* ci: add env variables for verbose logging

* chore: dummy sleep to shwocase error

* chore: dummy sleep to showcase error

* chore: remove dummy sleep

.github/workflows/python_test.yml

@@ -84,6 +84,9 @@ jobs:
         run: uv sync
       - name: Run integration tests
         run: make integration_tests_no_api_keys
+        env:
+          PYLEAK_LOG_LEVEL: debug # enable pyleak logging
+          DO_NOT_TRACK: true # disable telemetry reporting
 
   test-cli:
     name: Test CLI - Python ${{ matrix.python-version }}

pyproject.toml

@@ -175,6 +175,7 @@ dev = [
     "faker>=37.0.0",
     "pytest-timeout>=2.3.1",
     "pyyaml>=6.0.2",
+    "pyleak>=0.1.12",
 ]
 
 [tool.uv.sources]

src/backend/tests/integration/components/helpers/test_parse_json_data.py

@@ -3,7 +3,9 @@ from langflow.components.processing.parse_json_data import ParseJSONDataComponen
 from langflow.schema import Data
 
 from tests.integration.components.mock_components import TextToData
-from tests.integration.utils import ComponentInputHandle, run_single_component
+from tests.integration.utils import ComponentInputHandle, pyleak_marker, run_single_component
+
+pytestmark = pyleak_marker()
 
 
 async def test_from_data():

src/backend/tests/integration/components/inputs/test_chat_input.py

@@ -2,7 +2,9 @@ from langflow.components.input_output import ChatInput
 from langflow.memory import aget_messages
 from langflow.schema.message import Message
 
-from tests.integration.utils import run_single_component
+from tests.integration.utils import pyleak_marker, run_single_component
+
+pytestmark = pyleak_marker()
 
 
 async def test_default():

src/backend/tests/integration/components/inputs/test_text_input.py

@@ -1,7 +1,9 @@
 from langflow.components.input_output import TextInputComponent
 from langflow.schema.message import Message
 
-from tests.integration.utils import run_single_component
+from tests.integration.utils import pyleak_marker, run_single_component
+
+pytestmark = pyleak_marker()
 
 
 async def test_text_input():

src/backend/tests/integration/components/prompts/test_prompt.py

@@ -1,7 +1,9 @@
 from langflow.components.processing import PromptComponent
 from langflow.schema.message import Message
 
-from tests.integration.utils import run_single_component
+from tests.integration.utils import pyleak_marker, run_single_component
+
+pytestmark = pyleak_marker()
 
 
 async def test():

src/backend/tests/integration/conftest.py

@@ -4,3 +4,7 @@ import pytest
 @pytest.fixture(autouse=True)
 def _start_app(client):
     pass
+
+
+def pytest_configure(config):
+    config.addinivalue_line("markers", "no_leaks: detect asyncio task leaks, thread leaks, and event loop blocking")

src/backend/tests/integration/flows/test_basic_prompting.py

@@ -3,9 +3,10 @@ from langflow.components.processing import PromptComponent
 from langflow.graph import Graph
 from langflow.schema.message import Message
 
-from tests.integration.utils import run_flow
+from tests.integration.utils import pyleak_marker, run_flow
 
 
+@pyleak_marker()
 async def test_simple_no_llm():
     graph = Graph()
     flow_input = graph.add_component(ChatInput())

src/backend/tests/integration/utils.py

@@ -3,6 +3,7 @@ import os
 import uuid
 from typing import Any
 
+import pytest
 import requests
 from astrapy.admin import parse_api_endpoint
 from langflow.api.v1.schemas import InputValueRequest
@@ -187,3 +188,11 @@ def build_component_instance_for_tests(version: str, module: str, file_name: str
     component = download_component_from_github(module, file_name, version)
     cc_class = eval_custom_component_code(component._code)
     return cc_class(**kwargs), component._code
+
+
+def pyleak_marker(**extra_args):
+    default_args = {
+        "enable_task_creation_tracking": True,  # log task creation stacks
+        "thread_name_filter": r"^(?!asyncio_\d+$).*",  # exclude `asyncio_{num}` threads
+    }
+    return pytest.mark.no_leaks(**default_args, **extra_args)

uv.lock

@@ -2309,7 +2309,7 @@ name = "exceptiongroup"
 version = "1.3.0"
 source = { registry = "https://pypi.org/simple" }
 dependencies = [
-    { name = "typing-extensions", marker = "python_full_version < '3.11'" },
+    { name = "typing-extensions", marker = "python_full_version < '3.13'" },
 ]
 sdist = { url = "https://files.pythonhosted.org/packages/0b/9f/a65090624ecf468cdca03533906e7c69ed7588582240cfe7cc9e770b50eb/exceptiongroup-1.3.0.tar.gz", hash = "sha256:b241f5885f560bc56a59ee63ca4c6a8bfa46ae4ad651af316d4e81817bb9fd88", size = 29749, upload-time = "2025-05-10T17:42:51.123Z" }
 wheels = [
@@ -4980,6 +4980,7 @@ dev = [
     { name = "pandas-stubs" },
     { name = "pre-commit" },
     { name = "pydantic-ai" },
+    { name = "pyleak" },
     { name = "pytest" },
     { name = "pytest-asyncio" },
     { name = "pytest-cov" },
@@ -5155,6 +5156,7 @@ dev = [
     { name = "pandas-stubs", specifier = ">=2.1.4.231227" },
     { name = "pre-commit", specifier = ">=3.7.0" },
     { name = "pydantic-ai", specifier = ">=0.0.19" },
+    { name = "pyleak", specifier = ">=0.1.12" },
     { name = "pytest", specifier = ">=8.2.0" },
     { name = "pytest-asyncio", specifier = ">=0.23.0" },
     { name = "pytest-cov", specifier = ">=5.0.0" },
@@ -8474,6 +8476,18 @@ version = "2.10"
 source = { registry = "https://pypi.org/simple" }
 sdist = { url = "https://files.pythonhosted.org/packages/5d/ab/34ec41718af73c00119d0351b7a2531d2ebddb51833a36448fc7b862be60/pylatexenc-2.10.tar.gz", hash = "sha256:3dd8fd84eb46dc30bee1e23eaab8d8fb5a7f507347b23e5f38ad9675c84f40d3", size = 162597, upload-time = "2021-04-06T07:56:07.854Z" }
 
+[[package]]
+name = "pyleak"
+version = "0.1.12"
+source = { registry = "https://pypi.org/simple" }
+dependencies = [
+    { name = "exceptiongroup" },
+]
+sdist = { url = "https://files.pythonhosted.org/packages/14/55/bdc246baf6870185555d6ebcb35a7361f9bb95ba3fd0ff295d8fc4ff9e6e/pyleak-0.1.12.tar.gz", hash = "sha256:6af479b2dd5d4c71ff2b33ba5eeccda04b2d248f884801cf414fc84777a636de", size = 104742, upload-time = "2025-07-01T12:04:44.708Z" }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/4d/08/e8bc7e2f63deca307575bcf98d112fe75f80ecd716d3dcc69330ad096fff/pyleak-0.1.12-py3-none-any.whl", hash = "sha256:17a1c8b11d89fdcee79f0a479378bd6de23de323754a81efe8d8d9550ac12863", size = 23762, upload-time = "2025-07-01T12:04:43.494Z" },
+]
+
 [[package]]
 name = "pylint"
 version = "3.3.7"