Wrong callback issue with gcouchbase

README.md

When I ignore GreenletExit during getting foo, getting bar on the same greenlet returns the result of foo instead of bar. It's a critical issue because we could not believe the result of any operations.

This example reproduces the case of "wrong callback". I tested this with couchbase-2.8.0. But I've been experiencing the issue from long time ago.

gcouchbase-wrong-callback-greenlet-exit.py

from gcouchbase.bucket import Bucket
import gevent


bucket = Bucket('couchbase://localhost/default')
bucket.upsert('foo', 'foo')
bucket.upsert('bar', 'bar')


def load_foo_and_bar_forever():
    while True:
        try:
            r = bucket.get('foo')
        except gevent.GreenletExit:
            continue
        else:
            assert r.value == 'foo', r
        try:
            r = bucket.get('bar')
        except gevent.GreenletExit:
            continue
        else:
            assert r.value == 'bar', r


def kill_greenlet_forever(g):
    while True:
        gevent.sleep(0.1)
        g.kill()


g = gevent.spawn(load_foo_and_bar_forever)
gevent.joinall([g, gevent.spawn(kill_greenlet_forever, g)])

gcouchbase-wrong-callback-timeout.py

from gcouchbase.bucket import Bucket
import gevent


bucket = Bucket('couchbase://localhost/default')
bucket.upsert('foo', 'foo')
bucket.upsert('bar', 'bar')


def load_foo_and_bar_within_timeout_forever():
    while True:
        try:
            with gevent.Timeout(0.0000001):
                r = bucket.get('foo')
        except gevent.Timeout:
            continue
        else:
            assert r.value == 'foo', r
        try:
            with gevent.Timeout(0.0000001):
                r = bucket.get('bar')
        except gevent.Timeout:
            continue
        else:
            assert r.value == 'bar', r


g = gevent.spawn(load_foo_and_bar_forever)
g.get()