client error when chain UPI=[] (unavailable), also perhaps file descriptor/other leak? about machi

[slfritchie]

More info, when running with the SASL app running & logging errors.

=CRASH REPORT==== 30-Oct-2015::21:41:22 ===
  crasher:
    initial call: machi_cr_client:init/1
    pid: <0.1933.4>
    registered_name: []
    exception exit: {{badmatch,[]},
                     [{machi_cr_client,do_append_head2,7,
                          [{file,"src/machi_cr_client.erl"},{line,330}]},
                      {gen_server,try_handle_call,4,
                          [{file,"gen_server.erl"},{line,607}]},
                      {gen_server,handle_msg,5,
                          [{file,"gen_server.erl"},{line,639}]},
                      {proc_lib,init_p_do_apply,3,
                          [{file,"proc_lib.erl"},{line,237}]}]}
      in function  gen_server:terminate/7 (gen_server.erl, line 804)
[....]
    neighbour: [{pid,<0.182.0>},  %%% SLF note that this is a really "old" PID compared to the crasher
                  {registered_name,[]},
                  {initial_call,{erlang,apply,2}},
                  {current_function,{gen,do_call,4}},
                  {ancestors,[]},
                  {messages,
                   [{#Ref<0.0.0.8917>,{error,partition}},
[... a few hundred messages more ...]
                  {links,
                   [<0.31733.1>,<0.15066.2>,<0.22243.3>,<0.28288.3>,
                    <0.31857.3>,<0.4687.4>,<0.4779.4>,<0.4867.4>,<0.4907.4>,
[... very roughly, about 100,000 other process links ...]
                  {dictionary,
                   [{{memo,eqc_statem,non_interfering,
                      {machi_ap_repair_eqc,
                       {state,4,
                        {1445,935441,287549},
                        false,
                        [a,b,c,d],
                        [{a,a_chmgr},{b,b_chmgr},{c,c_chmgr},{d,d_chmgr}],
                        [{a,<0.8424.1>},
                         {b,<0.8425.1>},
                         {c,<0.8427.1>},
                         {d,<0.8429.1>}],
                        [{a,<0.8430.1>},
                         {b,<0.8437.1>},
                         {c,<0.8444.1>},
                         {d,<0.8451.1>},
                         {a,<0.8458.1>},
                         {b,<0.8465.1>},
                         {c,<0.8472.1>},
                         {d,<0.8479.1>},
                         {a,<0.8486.1>},
                         {b,<0.8493.1>},
                         {c,<0.8500.1>},
                         {d,<0.8507.1>}]},
[... are really super enormous process dictionary continues ...]

[slfritchie]

At the start of each QuickCheck test case, I check the # of procs and the proc limit:

.process_count = 3563 of 262144,
.process_count = 3544 of 262144,
.process_count = 4792 of 262144,
[...]
.process_count = 20874 of 262144,
.process_count = 21020 of 262144,
.process_count = 20879 of 262144,
.process_count = 20950 of 262144,
.process_count = 21060 of 262144,
.process_count = 21308 of 262144,
[...]

[shino]

One apparent point of process leak is that I forgot to stop some client processes in #state of EQC side 🙈