Gitlab-CI only:variables doesn't work as intended

Summary

Gitlab-CI's only.variables gets validated when it should not

Steps to reproduce

Here is a sample job configuration:

stages:
- run

start-staging-1:
  stage: run
  image: python:latest
  only:
    variables:
      - $ACTION == "start"
      - $ENV == "staging-1"
  script:
  - pip install awscli
  - aws ec2 start-instances --instance-ids ...

stop-staging-1:
  stage: run
  image: python:latest
  only:
    variables:
      - $ACTION == "stop"
      - $ENV == "staging-1"
  script:
  - pip install awscli
  - aws ec2 stop-instances --instance-ids ...

I then trigger jobs using schedules with the following ENV vars:

What is the current bug behavior?

The current observed behavior is that at each run, both the start and stop jobs are launched.

What is the expected correct behavior?

Only the job matching the ACTION should be started

Results of GitLab environment info

Expand for output related to GitLab environment info

System information
System:		Traceback (most recent call last): File "/usr/bin/lsb_release", line 28, in  import lsb_release ImportError: No module named 'lsb_release'
Current User:	git
Using RVM:	no
Ruby Version:	2.5.3p105
Gem Version:	2.7.6
Bundler Version:1.16.6
Rake Version:	12.3.2
Redis Version:	3.2.12
Git Version:	2.18.1
Sidekiq Version:5.2.5
Go Version:	unknown
GitLab information
Version:	11.9.8
Revision:	48528bc
Directory:	/opt/gitlab/embedded/service/gitlab-rails
DB Adapter:	postgresql
URL:		https://
HTTP Clone URL:	https:///some-group/some-project.git
SSH Clone URL:	ssh://git@:2233/some-group/some-project.git
Using LDAP:	no
Using Omniauth:	yes
Omniauth Providers: azure_oauth2
GitLab Shell
Version:	8.7.1
Repository storage paths:

• default: /var/opt/gitlab/git-data/repositories GitLab Shell path: /opt/gitlab/embedded/service/gitlab-shell Git: /opt/gitlab/embedded/bin/git

Results of GitLab application Check

Expand for output related to the GitLab application check

Checking GitLab subtasks ...
Checking GitLab Shell ...
GitLab Shell: ... GitLab Shell version >= 8.7.1 ? ... OK (8.7.1)
Running /opt/gitlab/embedded/service/gitlab-shell/bin/check
Check GitLab API access: OK
Redis available via internal API: OK
Access to /var/opt/gitlab/.ssh/authorized_keys: OK
gitlab-shell self-check successful
Checking GitLab Shell ... Finished
Checking Gitaly ...
Gitaly: ... default ... OK
Checking Gitaly ... Finished
Checking Sidekiq ...
Sidekiq: ... Running? ... yes
Number of Sidekiq processes ... 1
Checking Sidekiq ... Finished
Checking Incoming Email ...
Incoming Email: ... Reply by email is disabled in config/gitlab.yml
Checking Incoming Email ... Finished
Checking LDAP ...
LDAP: ... LDAP is disabled in config/gitlab.yml
Checking LDAP ... Finished
Checking GitLab App ...
Git configured correctly? ... yes
Database config exists? ... yes
All migrations up? ... yes
Database contains orphaned GroupMembers? ... no
GitLab config exists? ... yes
GitLab config up to date? ... yes
Log directory writable? ... yes
Tmp directory writable? ... yes
Uploads directory exists? ... yes
Uploads directory has correct permissions? ... yes
Uploads directory tmp has correct permissions? ... yes
Init script exists? ... skipped (omnibus-gitlab has no init script)
Init script up-to-date? ... skipped (omnibus-gitlab has no init script)
Projects have namespace: ...
--all yes--
Redis version >= 2.8.0? ... yes
Ruby version >= 2.3.5 ? ... yes (2.5.3)
Git version >= 2.18.0 ? ... yes (2.18.1)
Git user has default SSH configuration? ... no
Try fixing it:
mkdir ~/gitlab-check-backup-1555839823
sudo mv /var/opt/gitlab/.ssh/authorized_keys.backup ~/gitlab-check-backup-1555839823
For more information see:
doc/ssh/README.md in section "SSH on the GitLab server"
Please fix the error above and rerun the checks.
Active users: ... 39
Checking GitLab App ... Finished
Checking GitLab subtasks ... Finished

Possible fixes

No, but ugly workaround for now is to add in the script section:

if [ $ACTION != "start" ] || [ $ENV != "staging-1" ]; then exit 0; fi