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    Back Out Submitted Changelist    What is the difference between these two  In what situations should I use either one

User · Answer

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  rarr  multiple rotations Backout  rarr  back out of a single car parking space   I hope this helps

User · Answer

Backout restores or undoes our changes  The way it does this is that  P4 undoes the changes in a changelist  default or new  on our local workspace  We then have to submit commit this backedout changelist as we do other changeslists  The second part is important here  as it doesn t automatically backout the changelist on the server  we have to submit the backedout changelist  which makes sense after you do it  but i was initially assuming it does that automatically    As pointed by others  Rollback has greater powers - It can restore changes to a specific date  changelist or a revision

User · Answer

Reverse a changelist submission  You cannot undo a successful changelist submission  but you can reverse previously submitted changes in two ways   Rollback restores a file or set of files back to a specified changelist  date or revision  Any changes made after that point in time are not retained  Back out removes specific changes made at a given changelist  date or revision but allows a user to keep changes made in subsequent revisions   For details please refer to https   www perforce com perforce r13 1 manuals p4v Working with changelists html

User · Answer

Both of these operations restore a set of files to a previous state and are essentially faster  safer ways of undoing mistakes than using the p4 obliterate command  and you don t need admin access to use them      In the case of  Rollback      this could be any number of files  even an entire depot   You can tell it to rollback to a specific revision  changelist  or label   The files are restored to the state they were in at the time of creation of that revision  changelist  or label   In the case of  Back Out Submitted Changelist         the restore operation is restricted to the files that were submitted in changelist         Those files are restored to the state they were in before you submitted that changelist  provided no changes have been made to those files since   If subsequent changes have been made to any of those files  Perforce will tell you that those files are now out of date   You will have to sync to the head revision and then resolve the differences   This way you don t inadvertently clobber any changes that you actually want to keep   Both operations work by essentially submitting old revisions as new revisions   When you perform a  Rollback      you are restoring the files to the state they were in at a specific point in time  regardless of what has happened to them since   When you perform a  Back out      you are attempting to undo the changes you made at a specific point in time  while maintaining the changes that have occurred since

User · Answer

I explain this to users by comparing Perforce changelists to a stack  from data structures    Backing out removes one item from anywhere in the stack   Rolling back removes n items from the top of the stack

User · Answer

Rollback    will prompt you to select a folder to rollback  ie  it will work on specific folders  and you can rollback to labels or changlists or dates   Back out works on the files in specific changelists

[perforce] What is the difference between "Rollback..." and "Back Out Submitted Changelist #####" in Perforce P4V

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