Segfault in ecan when using ghost

[amebel]

Steps to take to reproduce segfault

1. Build and install opencog, and atomspace after running the following

cmake -DCMAKE_DISABLE_FIND_PACKAGE_Python3Interp=TRUE -DCMAKE_BUILD_TYPE=DEBUG ..

2. Start relex by running opencog-server.sh
3. Start cogserver using the following configuration file, load-opencog.txt (.txt extenstion is used for loading to github)

gdb -ex r --args guile -l load-opencog.txt

4. Load ghost rules

cd /loving-ai-ghost/bin 
bash run.sh

5. From the terminal where the cogserver is started, interact with the bot until it segfaults

scheme@(guile-user)> (ghost "hi")
[2018-12-28 10:23:55:845] [INFO] [say] (|happy,3| Hi ! My name is Sophia. What's yours ?)
...
...
scheme@(guile-user)> (ghost "amen")
 [2018-12-28 10:24:11:434] [INFO] [say] (|happy,.7,5| Good to meet you , amen ! Thanks so much for taking the time to come and talk with me today.)
...

Repo states

loving-ai-ghost = a3e6f43
opencog sha = d68351c
atomspace sha = c121f0f
cogutil sha = f85718c
relex sha = 6fb3873

[linas]

Screenshots!? One can't control-F in a browser to search it. And google cannot index the contents.

Anyway, opencog/atomspace#1976 should "hide" this bug. There is still some bug in the diffusion agent, because it is sending the atomspace some atoms that are not in any atomspace.

It would be easiest to fix the diffusion agents before installing the fix opencog/atomspace#1976

Also, it would be best if the diffusion agents got some unit tests, to verify that they work correctly.