exp show: branch names are toggling randomly

[aguschin]

Bug Report

Description

I cloned repo get-started-experiments and created new branch. Now dvc exp show shows me different branch names from time to time. It also happens if you move back to main branch.

Reproduce

1. git clone https://github.com/iterative/get-started-experiments
2. cd get-started-experiments
3. dvc pull
4. git checkout -b other-branch
5. dvc exp show --no-pager

Run last command few times

Environment information

Output of dvc doctor:

$ dvc doctor
DVC version: 2.1.0 (brew)
---------------------------------
Platform: Python 3.9.5 on macOS-10.16-x86_64-i386-64bit
Supports: azure, gdrive, gs, http, https, s3, ssh, oss, webdav, webdavs
Cache types: reflink, hardlink, symlink
Cache directory: apfs on /dev/disk1s5s1
Caches: local
Remotes: https
Workspace directory: apfs on /dev/disk1s5s1
Repo: dvc, git

Additional Information (if any):

Tried the same with the latest dev version 2.1.0+9dda6b, the bug persists

[casperdcl]

Ideally all aliases (refs with the same HEAD) should be shown, or at least the same one consistently (e.g. first alphabetically. I don't think Git keepa a record of when an alias branch was created so no way to use the last one created, I think).

[pmrowla]

exp show is being changed to always show git SHA's by default, along with a single branch or tag name (w/tag's given higher priority) for that SHA. The SHA will remain unchanged, and ideally we should consistently choose a ref, but I don't think this is high priority right now.

[dberenbaum]

@pmrowla Isn't exp show limited to the experiments derived from the current HEAD by default? If so, would it make sense to at least prioritize the current branch over others?

[pmrowla]

@dberenbaum sure, that's one way we could make it more consistent, at least for the case where HEAD is actually a branch, and there are no tags that also point to HEAD.

For reference though, at the time we actually try to determine a git ref name for an experiment row, we aren't using the string HEAD (like in git describe HEAD), we're using a SHA. Obviously we can check and see if HEAD resolves to the same SHA, and then decide how our SHA should be described from there, but it's not entirely straightforward.

[karajan1001]

@aguschin Does it still happen on your computer? I tried on my one can't reproduce it for now.

[aguschin]

@karajan1001, it's because the tag has the higher priority (see @pmrowla answer above). Try to delete tag and then repeat this for few times: