How do you revert a file to a revision within an integration in Perforce?

I have two branches, let's call them mainline and dev1. I regularly integrate a file from mainline to dev1. The last-but-one time I integrated the file, it was at revision 3 in mainline. The last time, it was at revision 5.

Now for mysterious reasons lost to the sands of time, I want to work in de开发者_StackOverflow中文版v1 with revision 4 of the file from mainline. Is that possible?

I can't integrate it across as P4V complains that all revisions have already been integrated.

I've tried right-click->get this revision on the revision graph, but that only updates which version of the file I have in mainline, not in dev1.

You can force an integration regardless of the integration history. On the Integrate options dialog there is a button labeled "Advanced Options".

On the Advanced Options dialog, check the option to "Force integration on all revisions, disregarding integration history (-f)". This will allow you to get revision 4 of that file from mainline into dev1.