pkg assert error when locking libressl package

[Eduardo Morras]

Hi,

I'm making a switch from openssl to libressl. I installed from ports
some apps to use it explicitly, but when I use pkg to upgrade all
packages, it (pkg) insist to remove libressl and install openssl and
reinstall my "libressl-compiled-from-ports-apps", so I locked libressl
with `#pkg lock libressl` and the other apps (Postgresql9.5*,
nginx, ...)

After lock them, I retry the `#pkg upgrade` but get this assertion fail.

Processing candidates (56 candidates): 100%
Checking integrity...
libressl-2.3.5 is locked and may not be modified
Assertion failed: (cun != NULL), function
pkg_conflicts_check_chain_conflict, file pkg_jobs_conflicts.c, line
498. Child process pid=65545 terminated abnormally: Abort trap

My system:

x86_64, Freebsd 10.2-RELEASE-p19 (latest)

pkg version:
 # pkg version | grep pkg
pkg-1.8.4                          <

And here are the questions:

a) Is it a bug in pkg or a expected assert on this scenary? Do any pkg
developer need more info? 

b) How can I switch, in a safe way, from openssl to libressl? 

c) If switch is not possible for FreeBSD 10.2, how can they `live
together`? 

d) Anyone knows if there are plans for FreeBSD11 base (/usr/src/) on
this topic?

Thanks in advance


---   ---
Eduardo Morras <emorrasg at yahoo.es>