Re: Pinned references?

[Patrick Steinhardt <ps@pks.im>]

On Thu, Jun 18, 2026 at 08:37:26PM +0200, Erik Östlund wrote:
> I'd like to be able to express a reference together with an expected
> object ID, for example with strawman syntax like:
> 
> refs/tags/v1.2.3?oid=a1b2c3d4
> 
> The intended semantics would be that both the reference and object ID
> must exist, and Git should fail if the reference does not resolve to the
> specified object ID.
> 
> Tags are nice because they convey human meaning. Object IDs are nice
> because they are immutable. As it is, I often have to choose between the
> two, or represent them separately in external tooling.
> 
> Is there existing terminology, prior discussion, or an accepted Git-native
> approach for this kind of "ref plus expected OID" invariant? I
> searched both the Git reference documentation and the mailing list
> archives, but couldn't find what I was looking for.

You can already kind of do this:

    $ git rev-parse v2.54.0
    0b13e48a3a30cdfa94e8ef842e24d6045ab3d015

    $ git rev-parse v2.54.0-0-g0b13e48a3
    0b13e48a3a30cdfa94e8ef842e24d6045ab3d015

    $ git rev-parse v2.54.0-0-g95e20213f
    95e20213faefeb95df29277c58ac1980ab68f701

This is described under gitrevisions(7), `<describeOutput>`. The only
gotcha is that this format will not verify that the tag and the object
ID actually match. But other than that it gives you the ability to have
both the human-readable name and the machine-readable commit ID in
there.

As said, we don't verify that those two revisions actually match. So in
the case where they don't the result is certainly going to be lots of
confusion. It certainly is one of the more surprising syntaxes that we
have in Git.

Patrick