Invert a test in .gitlab-ci.yml

Question

I would like to prevent TODO comments (or other problematic strings) from being checked in with a gitlab CI test rule. I added the last line here:

.job_template: &template_test
  image: python:3.6-stretch
  tags:
    - python
  # ...

stages:
  - test

test:
  <<: *template_test
  stage: test
  script:
    - flake8 *.py
    - ! grep TODO *.py

But when I look at the output of the runner, it fails:

$ flake8 *.py
$ grep TODO *.py
ERROR: Job failed: exit code 1

It seems like Gitlab swallowed the exclamation mark !, used in the shell to negate the return value of grep.

Answer 1

A line with the exclamation mark (! grep ...) at the beginning must be quoted. However, even this ('! grep ...') will not work here, return code will always be zero. I got the solution from https://stackoverflow.com/a/31549913/491884, a subshell must be started because GitLab CI starts the shell with set -e. This should work and is reasonably short:

script:
...
- (! grep TODO *.py)