Data context is always empty in a log

[Vitalii Solodilov]

Workflow example:
---
version: '2.0'

flow:
  type: direct
  input:
    - test: test

  tasks:
    task1:
      action: std.echo output="Hi"
      publish:
        # res: <% task().result %>
        invalid_res: <% task().res %>

At the same time context is empty in a log:

2018-07-30 01:41:21.525 25808 DEBUG mistral.expressions.yaql_expression [req-0e6ccbb7-433b-4044-998c-78c3fae1d670 - - - - -] Start to evaluate YAQL expression. [expression='<% task().result %>', context={}] evaluate /home/mcdoker18/opensource/mistral/mistral/expressions/yaql_expression.py:158

or

2018-07-30 01:44:55.941 26913 ERROR mistral.expressions.yaql_expression [req-742911aa-a72c-4afa-a001-135a6ece2b49 - - - - -] Can not evaluate YAQL expression [expression=task().res, error=u'res', context={}]

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/586907

[Renat Akhmerov (rakhmerov)]

What do you want to achieve? Data context is a user-related data and has potentially an unlimited size. We can't log it. We can only log a trimmed version of it but it's not much useful practically.

[OpenStack Infra (hudson-openstack)]

Change abandoned by Renat Akhmerov (<email address hidden>) on branch: master
Review: https://review.opendev.org/586907
Reason: No changes for too long.