Freezing method calls for creating queues, exchanges and bindings

In both Pika 0.13.0 and 1.0.0b1, some method calls for creating queues, exchanges and bindings are freezing (blocking forever instead of returning or raising an exception) with some arguments. These unexpected behaviours are emphasized in bold below.

queue_declare

• queue_declare() OK, raises TypeError: queue_declare() missing 1 required positional argument: ‘queue’ in Pika 1.0.0b1, creates a queue with a unique name in Pika 0.13.0.
• queue_declare(queue=None) Unexpected, freezes instead of creating a queue with a unique name.
• queue_declare(queue="") OK, creates a queue with a unique name.

exchange_declare

• exchange_declare() Unexpected, freezes instead of raising TypeError: exchange_declare() missing 1 required positional argument: ‘queue’.
• exchange_declare(exchange=None) Unexpected, freezes instead of raising pika.exceptions.ChannelClosed: (403, ‘ACCESS_REFUSED - operation not permitted on the default exchange’).
• exchange_declare(exchange="") OK, raises pika.exceptions.ChannelClosed: (403, ‘ACCESS_REFUSED - operation not permitted on the default exchange’).

queue_bind

• queue_bind() OK, raises TypeError: queue_bind() missing 2 required positional arguments: ‘queue’ and ‘exchange’;
• queue_bind(queue=None, exchange=None, routing_key=None) Unexpected, freezes instead of raising pika.exceptions.ChannelClosed: (403, ‘ACCESS_REFUSED - operation not permitted on the default exchange’).
• queue_bind(queue="", exchange="", routing_key="") OK, raises pika.exceptions.ChannelClosed: (403, ‘ACCESS_REFUSED - operation not permitted on the default exchange’).

exchange_bind

• exchange_bind() Unexpected, freezes instead of raising TypeError: exchange_declare() missing 2 required positional arguments: ‘destination’ and ‘source’.
• exchange_bind(destination=None, source=None, routing_key=None) Unexpected, freezes instead of raising pika.exceptions.ChannelClosed: (403, ‘ACCESS_REFUSED - operation not permitted on the default exchange’).
• exchange_bind(destination="", source="", routing_key="") OK, raises pika.exceptions.ChannelClosed: (403, ‘ACCESS_REFUSED - operation not permitted on the default exchange’).

I used a BlockingChannel for all the method calls. For instance:

import pika

parameters = pika.ConnectionParameters()

with pika.BlockingConnection(parameters) as connection:
    channel = connection.channel()
    channel.queue_declare(queue=None)

[lukebakken]

@maggyero I will make those changes, thanks.

[maggyero]

@lukebakken Okay thanks. So if I understood well you added validation for addressing the case:

• exchange_bind(destination=None, source=None, routing_key=None)

That way instead of freezing the function validators.require_string will raise:

TypeError: destination must be a str or unicode str, but got ‘None’

which addresses one of the six unexpected behaviours that I listed. (And in Pika 1.0.0b2 the function validators.require_string will raise a ValueError instead of the current TypeError.)

I see also that on 22 January 2019 you addressed three other cases by adding the same validation:

• queue_declare(queue=None)
• queue_bind(queue=None, exchange=None, routing_key=None)
• exchange_declare(exchange=None)

So there remains two cases to address:

• exchange_declare()
• exchange_bind()

They can be addressed by simply removing the default None arguments in the definitions:

def exchange_declare(self,
                     exchange=None,  # to be replaced by: exchange
                     exchange_type='direct',
                     passive=False,
                     durable=False,
                     auto_delete=False,
                     internal=False,
                     arguments=None):

and

def exchange_bind(self,
                  destination=None,  # to be replaced by: destination
                  source=None,       # to be replaced by: source
                  routing_key='',
                  arguments=None):

That way they the call exchange_declare() would raise

TypeError: exchange_declare() missing 1 required positional argument: ‘exchange’

and the call exchange_bind() would raise:

TypeError: exchange_bind() missing 2 required positional arguments: ‘destination’ and ‘source’

which is consistent with the symmetric calls queue_declare() and queue_bind() which already raise these TypeError.