Why does my merge job always end with everything up-to-date?

Question

I want to merge dev and master branch every midnight and create a logfile of the application date wise. i.e dev-app-dd-mm-yy.log or master-app-dd-mm-yy.log.

My app is running on docker and ci is done by gitlab.

  rules: # Workflow rules
    - if: $CI_PIPELINE_SOURCE == "schedule" && $CI_COMMIT_BRANCH == "main"
      variables:
        TAG: latest
   - if: $CI_PIPELINE_SOURCE != "schedule"
       variables
         TAG: $CI_PIPELINE_IID

merge: # merge job to merge branches at midnight
  stage: merge
  script:
    - git merge origin/dev && git push

build image:
  stage: docker
  script:
    - docker build  && push # build and push docker images

.deploy_template: &deploy_config
  script:
    - echo "Deploying application..."
    - ssh -o StrictHostKeyChecking=no user@myhost # ssh into server
      docker stop PRIVIOUS_CONTAINER; 
      docker rm  PRIVIOUS_CONTAINER;
      touch $ENV-app-$(date +%d.%m.%Y).log && # create a logfile with date
      docker run -d -p 8080:8080
      -v $ENV-app-$(date +%d.%m.%Y).log:/app/jdbcApp.log 
      --name app app-image:$TAG"
    - echo "Application successfully deployed."

deploy:
  stage: deploy
  <<: *deploy_config
  when: on_success   

deploy latest:
  stage: deploy
  <<: *deploy_config
  when: on_failure

Now, problem with this is merge job never returns 1. it returns "Everything up-to-date" and job passes. So no deploy is triggered when there are no push made on dev branch.