To re roll broken patch here are the steps, we will use commerce_stripe module as example,
- git clone --branch 8.x-1.x https://git.drupalcode.org/project/commerce_stripe.git
- go to issue page and find date of last working patch
- git log -1 --before="2 Dec 2018" to find hash of commit to use
- git checkout -b stripe_reroll 61565a7 to go to that commit
- git apply --index some.patch try to apply patch to see if it works
- git commit -m "Applying patch from issue 821716 comment 118571"
- git rebase 8.x-1.x to rebase out changes on top of current dev
- solve conflicts that occur when rebasing, run git add . to add all the resolved files
- git rebase --continue to continue doing this and repeat no.8
- Do no 8 and 9 until you get "Applying: Applying patch from issue 821716 comment 118571"
- Create a new patch, git diff 8.x-1.x stripe_reroll > new.patch
- Try new patch with git checkout 8.x-1.x and then
- git apply --check new.patch to see if it all works out
- if all is ok, then submit this patch to issue queue for others to use it