Did you consider _not_ re-indenting the entire code base and rely on the auto formatters of contributing people? Did you consider re-formatting parts of the code step-by-step, beginning with code that's not frequently changed?
Didn't know about the feature that ignores commits in git-blame, thank you for that.
I didn't consider doing it step by step, no, but I'm not sure how I would really achieve that effectively. The reality is that the bulk of PRs are submitted by the team, and it's straightforward to get everyone to get their code in before this change, pause merges, rebase, and then continue as normal. I'd rather go for the "rip the band-aid off" method.
That's what I was worried about, but I guess you can't have merge conflicts if you freeze the code.
Suppose you couldn't freeze the code, then what would you have done?