Dynamic Configuration values don't work with nested objects

[longfei-zhang]

I use the following cmd to set a key in the datastore.
$ st2 key set -e smtp_account.me.password "I'm Encrypted"

and here are my email pack config /opt/stackstorm/configs/email.yaml

---
smtp_accounts:
  - name: name
    password: "{{ st2kv.system.smtp_account.me.password }}"

(followed by the rest of the account configuration).

This is based on the email pack's config.schema.yaml, which contains this:

imap_accounts:
  description: "IMAP accounts"
  type: "array"
  required: true
  items:
    type: "object"
    required: true
    properties:
      name:
        description: "Name of the account"
        type: "string"
        secret: false
        required: true
      server:
        description: "Email server name - e.g. imap.gmail.com"
        type: "string"
        secret: false
        required: true
      username:
        description: "Mailbox username"
        type: "string"
        required: true
      password:
        description: "Mailbox password."
        type: "string"
        secret: true
        required: true

Running the email action fails:

Traceback (most recent call last):
  File "/opt/stackstorm/st2/lib/python2.7/site-packages/st2common/runners/python_action_wrapper.py", line 278, in <module>
    obj.run()
  File "/opt/stackstorm/st2/lib/python2.7/site-packages/st2common/runners/python_action_wrapper.py", line 171, in run
    output = action.run(**self._parameters)
  File "/opt/stackstorm/packs/email/actions/send_email.py", line 49, in run
    s.login(account_data['username'], account_data['password'])
  File "/usr/lib64/python2.7/smtplib.py", line 621, in login
    raise SMTPAuthenticationError(code, resp)
smtplib.SMTPAuthenticationError: (460, 'ERR.LOGIN.PASSERR')

I added some log to see the password value in File "/opt/stackstorm/packs/email/actions/send_email.py", line 49.
It seems that we get
{{ st2kv.system.smtp_account.me.password }} as the password.

FYI
If I run the send email action and use {{ st2kv.system.smtp_account.me.password }} as the message
I can see the message's value is correct.

[LindsayHill]

From Slack - probably related to https://github.com/StackStorm/st2/blob/master/st2common/st2common/util/config_loader.py#L102-L138

...conditional for nested objects, but not nested lists