cas command always expects response STORED

[Michal Linhard]

memcached cas command can also result in response EXISTS and NOT_FOUND

see the following scenario:
$ echo -e "set a 0 0 1\r\n1\r" | nc test1 11211
STORED
$ echo -e "gets a\r" | nc test1 11211
VALUE a 0 1 281479271678120
1
END
$ echo -e "cas a 0 0 1 281479271678120\r\n2\r" | nc test1 11211
STORED
$ echo -e "cas a 0 0 1 281479271678120\r\n2\r" | nc test1 11211
EXISTS
$ echo -e "cas b 0 0 1 281479271678120\r\n2\r" | nc test1 11211
NOT_FOUND

python-memcached client v1.45 doesn't support these

[Sean Reifschneider (jafo)]

I can see that you would like EXISTS and NOT_FOUND could be useful to distinguish in this case, but the cas() function is documented to return non-zero on success. I'd half say this should be a different function, like cas_status() or something, that would return the 3 different values (SUCCESS, EXISTS and NOT_FOUND). I'd be reluctant to change the main cas() function, without comment from the wider group of users. Or maybe it could be some special class that tests 0/non-0, but also has methods for these extra status.

Comments?

[Michal Linhard (michal-linhard)]

This will be quite a delayed answer :-)

Yeah I can understand that you don't want to change the cas() function API

the cas_status function/variable would work for me.
I'd save inthere whatever is now read by server.expect("STORED") in the _set function.