Runner 15.7.0 DOCKER_AUTH_CONFIG stopped working when saved as file variable
Summary
We tried to upgrade our GitLab runner to version 15.7.0 (coming from 15.6.3). Since the upgrade to 15.7.0, our DOCKER_AUTH_CONFIG does not work anymore (images cannot be pulled because of missing credentials).
We store the DOCKER_AUTH_CONFIG variable as file variable, because our DOCKER_AUTH_CONFIG is really huge. Switching to type "variable" instead of "file" worked, but we need to stay at "file" because we exceed the environment size limit of our Windows based runners and will exceed the max environment size of our Linux runners, too.
We have a huge amount of registries, all protected with rotating usernames and passwords. Because of that our DOCKER_AUTH_CONFIG is really huge (at the moment 60 kilobytes, still growing significantly) - so we cannot switch back to variable type "variable".
We would love to see this fixed soon, because currently we cannot upgrade our runners anymore.