Thanks for your quick reply.
Pull Requests can access the Build Cache (read only) but can’t update it, only after the PR is merged.
I see, I missed this.
So if I want to automatically create cache for a specific branch, I need to run a build with push trigger instead of pull request trigger, am I right?
Is this restriction documented somewhere?
I read About caching document, but it seems like there is no comment about this restriction.