[YvesDup]

The proposal fixes this issue that can break the FIFO order of the queue.

With a finite size queue, when the queue is full after the retrieval of an item, a new slot is free and a pending putter is awaken. This free slot that can be stole by put_nowait statement that will insert an item before them of the pending putters including the woken putter.
IMO, a QueueFull exception should be raise with an explicit message

In same way, there is a similar bug when queue is empty. After the insertion of an item in an empty queue with pending getters, one of the pending getter is awaken to get this fresh item at the next iteration.
But this item can be get via a get_nowait statement before the awaken task.
IMO, a QueueEmpty exception should be raise with an explicit message.

• Issue: asyncio.Queue: putting items out of order when it is full #83055

[YvesDup]

@asvetlov : A draft PR with an another proposal.

This PR also fixes this issue for the following example:

async def simplier_get_case():
    async def get_and_print(q):
        item = await q.get()
        print(f"\tGET: {item}, {str(q) = }")
 
    q = asyncio.Queue(1)
    g = 3
    for n in range(g):
        asyncio.create_task(get_and_print(q))
    await asyncio.sleep(0.0)

    # queue full: 1 item in queue, 2 items waiting into the _putters
    n = 1
    print(f'PUT: {await q.put(n) or n}')
    n += 1
    # queue not empty: 1 item in queue, 2 tasks the _putters
 
    # steal the free solt
    try:
        print(f"\tGET_NOWAIT steal a free slot: {q.get_nowait()}")
    except:
        g -= 1
        print("Failed to GET_NOWAIT item".center(60, '-'))
  
    # get all items
    for _ in range(g):
        print(f'PUT: {await q.put(n) or n}')
        n += 1
    await asyncio.sleep(0.0)

asyncio.run(simplier_get_case())

[YvesDup]

Closed in favor of #160967