On 23 September 2013 14:17, Nicolas Cellier <nicolas.cellier.aka.nice@gmail.com> wrote:
Here is my 100% personal opinion:
I don't like the copyShuffle. To me, the rules are quite clear: sort shuffle reverse etc... -> perform modification in place sorted shuffled reversed etc... -> answer a copy I hope the methods comments are clear. Does PBE tells about these conventions? It would be a good thing.
And I don't like to have mutexes in base library, the less we have, the better. If a user is going to modify the same object concurrently, he/she takes care of mutual exclusion.
Especially since locks don't compose. If you _really_ cared about accessing something concurrently, you'd share immutable data structures. frank
2013/9/23 Max Leske <maxleske@gmail.com>
Sven suggested posting this on the list for discussion, so here you go:
Maybe this should be discussed on the list, your are going to break API.
Note that there is also #sort and #sorted with similar copy behavior.
Also, I am not sure that basic operations should use mutexes to protect themselves by default: there is a cost when you are a single threaded user. Even in Java there are synchronized and non-synchronized versions of collections. IMHO, the protection should happen in your app, and basic collections do not have to be thread safe.
Sven
#shuffle does not use Collection>>mutexForPicking as other users of #randomForPicking demonstrate. This can lead to race conditions (found in our application).
In addition, there are now #shuffle, #shuffled, #shuffleBy: and #shuffledBy: where #shuffled and #shuffledBy: shuffle a copy and answers that. This is very confusing.
I propose a fix where #shuffled and #shuffledBy: are renamed to #copyShuffle and #copyShuffledBy: and moved to the "copying" protocol. #shuffle and #copyShuffle will use the mutex to prevent race conditions.