I’m trying to set up GitHub rulesets for an old repo.

One thing that I can’t do is to add the rule “Require linear history” because when I enabled it I get this error

Require linear history
This branch must not contain merge commits.
abc....

where the abc.... commit is a commit from a couple of years ago

is there a way to enable the ruleset only for the new commits (the commits that aren’t in our main branch)?

I don’t want to rewrite the main history to remove all of the merge commits, I know in the end it will be the same code, but it will give a lot of headaches for the whole development team.