To fix a broken HEAD, run the following command:

pachctl delete commit <commit-ID>

When you delete a HEAD commit, Pachyderm performs the following actions:

• Changes HEADs of all the branches that had the bad commit as their HEAD to their bad commit’s parent and deletes the commit. The data in the deleted commit is lost. If the bad commit does not have a parent, Pachyderm sets the branch’s HEAD to a new empty commit.
• Interrupts all running jobs, including not only the jobs that use the bad commit as a direct input but also the ones farther downstream in your DAG.
• Deletes the output commits from the deleted jobs. All the actions listed above are applied to those commits as well.

⚠️

This command will only succeed if the HEAD commit has no children on any branch. pachctl delete commit will error when attempting to delete a HEAD commit with children.

ℹ️

Are you wondering how a HEAD commit can have children?

A commit can be the head of a branch and still have children. For instance, given a master branch in a repository named repo, if you branch master by running pachctl create branch repo@staging --head repo@master, the master’s HEAD will have an alias child on staging.