Hacker News Reader

Comment by ziml77 | Hacker News Reader

Seems like a sensible way to archive branches. It's not like a tag and branch are actually very different anyway, right? A tag is a pointer that always refers to the same commit while a branch is a pointer that follows commits forward. And for something that's archived, you don't need the pointer updating mechanism.

View on HN

> A tag is a pointer that always refers to the same commit

It's not guaranteed not to change. The UI just makes it harder to update.

And anyone whose coworkers replace tags on a regular basis will be familiar with the following message from git when pulling changes:

would clobber existing tag

Really wish my coworkers would leave old tags as they were heh.

A hook should be able to prevent that

Hooks only keep honest people honest :) and an LLM will happily clobber a tag and skip hooks while the user just spams “accept”.

Luckily commonly used forges for collaboration have the ability to make tags immutable. Any repository where multiple people collaborate on a project should have that feature enabled by default. I'm still waiting for the day where tags are immutable by default with no option exposed to change it.

I'm sure that would cause problems for some, but transitive labels already exist in Git: branches.

I dont find the idea of a immutable "descriptive" tag or branch to be that useful (I also dont find the differentiation of tags and branches to be useful either) I've seen plenty of repositories where tags end up being pretty ambiguous compared to each other or where "release-20xx" does not actually point to the official 20xx release. Immutable references are more typically handled by builders and lockfiles to which Git already has a superior immutable reference system, the commit hash.

I 100% agree on the latter (the tag != release is more of a project management issue), and the same concept applies to containers and their digest hashes. The main issue at the end of the day is the human one: most people don't like looking at hashes, nor do they provide context of progression. I would say "give both" and make sure they match on the end user side of things, but tags are the most common way (open source) software releases are denoted.

As long as we can create and delete tags, they will never be immutable, right?

The purpose of the forge is to be able to prevent this. Protected tags are usually a feature which provides a way to mark tags as untouchable, so removal would require a minimum level of trust to the repository on the platform. Otherwise, attempts to push tag deletions or changes for tags matching the protected pattern would be rejected/ignored.

Of course, the repository owner has unlimited privilege here, hence the last part of my prior comment.

Tags are just a text file with a name and the sha of the tag object (with the commit and some metadata/signatures as contents), last I checked. It's deliberately simple and thus almost impossible to actually lock it down in concrete terms.

Packed refs are a little more complicated but all of the storage formats in git are trivial to manually edit or write a tool to handle, in extremis.

That's the purpose of the forge platform, to provide a way to prevent changes to these files from being accept into the source repository. For example:

https://docs.github.com/en/repositories/configuring-branches...

https://docs.gitlab.com/user/project/protected_tags/

https://forgejo.org/docs/latest/user/protection/#protected-t...

That's true for local hooks, but neither a dishonest person nor an LLM can bypass a pre-receive hook on the server (as long as they don't have admin access).

Thanks, apparently most people here aren't familiar with server-side hooks.

Can't solve culture problems with technology, but we all know that by now, right?

I have a somewhat different use case, where a work project has a moving "latest" tag. I discovered then the --force param with git fetch --tag

Correct.

One is refs/heads/<name> and the other is refs/tags/<name>

Branches are expected to change. When a commit is authored, HEAD (the current branch) updates to that commit.

Tags are expected not to change (though they can).

Other difference (actually, more like a consequence of what you said) is that Git keeps reflogs for branches but not for tags

Reply on news.ycombinator.com