Cannot use variable for specifying role

[Abdullah Al Nahian]

Previously, I was using variable to locate role so that I can execute different role based on variables i pass through command line argument and using variable file.

In my playbook,

  roles:
    - build_init
    - plugins
    - "{{recipe_dir}}/{{recipe}}/cook"
 

And I run this from command line with 

ansible-playbook builder.yml -e "recipe=edef"

It worked fine in Ansible 1.7.1

Once I updated to Ansible 1.8.4 this stopped working and I get following error

ERROR: cannot find role in /opt/ekitchen/ansibles/ece/roles/{{recipe_dir}}/{{recipe}}/cook or /opt/ekitchen/ansibles/ece/{{recipe_dir}}/{{recipe}}/cook or /etc/ansible/roles/{{recipe_dir}}/{{recipe}}/cook

Is this a bug or is there any way or getting around this?

Thanks in advance.

- Nahian