This repo demonstrates some unexpected behaviour in Gitea's Docker registry - when running docker commands (docker login, docker pull, etc.) against a registry, a call is made against the server's ROOT_URL. If there is no server available at the ROOT_URL, this will result in an error.

Why does this matter? How would it be possible for the server to be up but the ROOT_URL be unavailable?

It's a considerable edge case, but - see this SO question. A situation where this could arise is:

• a particular image is a prerequisite for making the Gitea registry publicly available (say, as part of a Cloudflared Tunnel deployment)
• the image is provided by that registry, but referenced using an internally-available url rather than the public name which is used as ROOT_URL

("This is a edge case that we will not address - if you have an image that's a prerequisite for making a registry publicly-available, provide it from a different registry" would be a perfectly reasonable response to this "issue" - I just wanted to flag it up in case it genuinely is unexpected, and/or if there's a better way to address this situation)