Callback does not yield CallbackContext (sometimes)

[MaximilianJHuber]

I have had the issue of receiving:

ERROR: User routine for func_callback returned -500.
       Could not evaluate objective or constraints at the current point.

EXIT: Callback function error.

when I solve my unconstrained problem. I added a @show into eval_ga_wrapper and got:

(typeof(cb), cb, typeof(userdata_), userdata_) = (Array{Any,1}, Any[], Ptr{Nothing}, Ptr{Nothing} @0x00000000055ff620)

and sometimes a SEGFAULT:

Please submit a bug report with steps to reproduce this fault, and any error messages that follow (in their entirety). Thanks.
Exception: EXCEPTION_ACCESS_VIOLATION at 0x43a293f48 -- sig_match_fast at /home/Administrator/buildbot/worker/package_win64/build/src\gf.c:2089 [inlined]
jl_lookup_generic_ at /home/Administrator/buildbot/worker/package_win64/build/src\gf.c:2159 [inlined]
jl_apply_generic at /home/Administrator/buildbot/worker/package_win64/build/src\gf.c:2215
in expression starting at no file:0
sig_match_fast at /home/Administrator/buildbot/worker/package_win64/build/src\gf.c:2089 [inlined]
jl_lookup_generic_ at /home/Administrator/buildbot/worker/package_win64/build/src\gf.c:2159 [inlined]
jl_apply_generic at /home/Administrator/buildbot/worker/package_win64/build/src\gf.c:2215
eval_fc_wrapper at C:\Users\Max\.julia\packages\KNITRO\bwlno\src\kn_callbacks.jl:312

When I Base.GC.enable(false) before the solve, then there are no issues.
I tried to construct an MWE, but it is complicated.

[frapac]

This issue is related to #120 : I am currently working on a fix, that hopefully would be released in a few days.

[MaximilianJHuber]

Thank you! I close this issue in favor of #120.