The project-template feature I wrote is bugged. It was supposed to merge defined jobs with the one defined by a template but it is overwriting them:

Example:

• name: mediawiki/tools/release check-voter:
  • mw-tools-release-phplint template:
  • name: 'python-lint' prefix: 'mw-tools-release'

That will only generate the jobs from the template and discard the phplint job.

The root cause is in Zuul scheduler:

1. Finally merge the expansion with whatever has been already
2. defined for this project config_project.update(expanded)

dict.update() does not do a recursive merge. We need a new function that will recursively merge all values being dicts.

Version: wmf-deployment
Severity: normal