syn and syn_groups' local_member and member function args are not aligned

[Tankut (uordek)]

Hi,

syn:member written as;

member(GroupName, Pid) ->
syn_groups:member(GroupName, Pid).

but syn_groups:member is declared as;

member(Pid, GroupName)

as I checked syn_groups other functions, to make alignment with them, seems syn_groups:member should declare as

member(GroupName, Pid)

like syn_groups:leave function.

There is same issue for local_member on syn and syn_groups modules.

I've fixed these issues on
https://github.com/tsenturk/syn/pull/new/fix-syn-groups-member-local-member-declare

#56

but not sure, eventually it seems a breaking change.

[Roberto Ostinelli]

Thank you for your report. This is overly complicated: there's no need to break changes for this. The only issue here is a naming /spec mix up in the syn.erl helper module.

For instance with syn:member/2, the doc states:

syn:member(Pid, GroupName) -> boolean().

In the syn.erl module there's indeed an inversion of the naming parameter (nice catch) which is incorrect:

-spec member(GroupName :: any(), Pid :: pid()) -> boolean().
member(GroupName, Pid) ->
    syn_groups:member(GroupName, Pid).

but this is just a proxy to:

-spec member(Pid :: pid(), GroupName :: any()) -> boolean().
member(Pid, GroupName) ->
    case find_groups_entry_by_name_and_pid(GroupName, Pid) of
        undefined -> false;
        _ -> true
    end.

Which therefore receives the correct parameters.

So basically it's just a name shift, with no effect on functionality. syn:member/2 should have been:

-spec member(Pid :: pid(), GroupName :: any()) -> boolean().
member(Pid, GroupName) ->
    syn_groups:member(Pid, GroupName).

Same goes for syn:local_member/2. To fix this all is really needed is to invert the param names in the syn.erl module for these two functions.

Would you like to create a new pull request with only these changes?

[Tankut (uordek)]

Yes, sure I can prepare another pull request for this. here; #58

First, I've think like you mentioned in your comment then I've figured out that other syn_groups functions have (GroupName, Pid) like declaration except these two (member, local_member) therefore I've propose this change on syn_groups instead of syn.

about functionality, I'm not sure as you are right now.

I've figured out this issue because dialyzer does not like member and local_member calls, like following;

The function call will not succeed.

:syn.local_member(
<<69, 115, 105, 121, 111, 46, 69, 108, 101, 99, 116, 105, 111, 110, 46, 86, 111, 116, 101,
114, 46, 67, 104, 97, 105, 110>>,
_pid :: pid()
)

will never return since it differs in arguments with
positions 1st from the success typing arguments:

(pid(), any())

[Roberto Ostinelli]

Unfortunately your PR has merge conflict because of recent changes in master.
Ok no worries, I will take this and fix the naming asap.

Thank you for your help.

[Tankut (uordek)]

ops, I'm quite sure I did create without any conlift but after all it possible :) sorry about it.
I hope, I could help.
Your welcome & thank you for this project.

[Roberto Ostinelli]

All changes are now up. Thank you for your help.