What is the difference between “Rollback…” and “Back Out Submitted Changelist #####” in Perforce P4V

Question

I want to reverse the changes from one of my checkins. In the right-click context menu of the particular changelist, there are these two options:

• Rollback...

Answer 1

At its simplest, the difference is one of plurality:

• Backout backs out of a single changelist (whether the most recent or not). i.e. it undoes a single changelist.
• Rollback rolls back changes as much as it needs to in order to get to a previous changelist. i.e. it undoes multiple changelists.

I used to forget which one is which and end up having to look it up many times. To fix this problem, imagine rolling back as several rotations then hopefully the fact that rollback is plural will help you (and me!) remember which one is which. Backout sounds 'less plural' than rollback to me. Imagine backing out of a single parking space.

So, the mnemonic is:

• Rollback → multiple rotations
• Backout → back out of a single car parking space

I hope this helps!