python sdk 4.3.5 collection.repalce issue

[Tan-Fei-Fei]

replace(
key=new_data["id"],
value=new_data,
opts=ReplaceOptions(
# cas=old.cas, # This parameter does not work as expected (does not take effect) in Couchbase Python SDK 4.3.5
durability=ServerDurability(
level=DurabilityLevel.PERSIST_TO_MAJORITY
)
),
cas=old_cas, # This parameter works as expected (takes effect) in Couchbase Python SDK 4.3.5
)

Explanation:

In the Couchbase Python SDK 4.3.5, there is an issue where specifying the 'cas' parameter inside the ReplaceOptions object

(e.g., cas=old.cas) does not function correctly and does not take effect. However, passing the 'cas' parameter directly

to the replace function (outside of the ReplaceOptions object) works as intended.

[thejcfactor]

Hi @Tan-Fei-Fei -- Can you provide some more details on how you are validating if the CAS is working properly?

Maybe there is a typo in your example? What does not work is cas=old.cas and what does work is cas=old_cas which do not appear to be the same thing.

We test cas w/ various operation's options blocks (including replace()), so I would be surprised if passing in cas to ReplaceOptions is not working. I have provided a small sample below and the output is as I would expect (e.g. no CasMismatchException when providing the correct cas and then a CasMismatchException with an incorrect cas).

from couchbase.auth import PasswordAuthenticator
from couchbase.cluster import Cluster
from couchbase.exceptions import CasMismatchException
from couchbase.options import ClusterOptions, ReplaceOptions

def main() -> None:
    # start user info
    endpoint = 'localhost'
    username = 'Administrator'
    password = 'password'
    bucket_name = 'default'
    connstr = f'couchbase://{endpoint}'
    # end user info

    auth = PasswordAuthenticator(username, password)
    cluster = Cluster(connstr, ClusterOptions(auth))
    bucket = cluster.bucket("default")
    collection = bucket.default_collection()

    test_key = 'test-key'
    collection.upsert(test_key, {'foo': 'bar'})
    get_res = collection.get(test_key)
    print(f'Get result: {get_res.content_as[str]}')
    get_cas = get_res.cas
    print(f'CAS: {get_cas}')
    collection.replace(test_key, {'foo': 'baz'}, ReplaceOptions(cas=get_cas))
    get_res1 = collection.get(test_key)
    print(f'Get result: {get_res1.content_as[str]}')
    collection.upsert(test_key, {'foo': 'bar'})
    try:
        collection.replace(test_key, {'foo': 'baz'}, ReplaceOptions(cas=get_cas))
    except CasMismatchException as e:
        print(f'CAS mismatch exception: {e}')
    collection.remove(test_key)


if __name__ == '__main__':
    main()

output (error output is reduced for simplicity):

Get result: {'foo': 'bar'}
CAS: 1744679141054808064
Get result: {'foo': 'baz'}
CAS mismatch exception: CasMismatchException(...)