File shows up as changed when reverting changes from an earlier patch

[benjifisher]

I am reviewing https://www.drupal.org/project/drupal/issues/2925899.

I previously applied the patch from Comment 52. (It would be great if the comment number was part of the commit message.) The patch in Comment 62 reverted the changes to one file. When I applied the patch using this project, the reverted file was still changed.

IIUC, the strategy is to apply the latest patch to a temporary branch, then merge that branch into the existing branch for the issue. I think what we really want is to make the HEAD of the current branch an ancestor of the HEAD of the temporary branch.