Leaked concurrency handle (ARCH2085)

Key python.performance.leaked-concurrency-handle · Severity warning · Category performance

A lock acquired without a guaranteed release is never freed if an error occurs, causing deadlock. Bound its lifetime with with.

Incorrect

import threading

lock = threading.Lock()

def increment(counter):
    lock.acquire()
    counter.value += 1
    lock.release()

Correct

import threading

lock = threading.Lock()

def increment(counter):
    with lock:
        counter.value += 1

Fix

Acquire locks with with lock:, join threads, or wrap handles in a context manager.