annoyance with .git-blame-ignore-revs

I like the ignore-revs file, but I run into a problem with my setup:
because I keep checkouts of all branches as worktrees, then all branches
share the same .git/config file.  So if I put the recommended stanza for
[blame] in it, then 'git blame' complains in branches older than 13,
since those don't have the file:

$ git blame configure
fatal: could not open object name list: .git-blame-ignore-revs

My first workaround was to add empty .git-blame-ignore-revs in all
checkouts.  This was moderately ok (shrug), until after a recent `tig`
upgrade the empty file started to show up in the history as an untracked
file.

So I'm now by the second workaround, which is to move the [blame]
section of config to a separate file, and use a [includeIf] sections
like this:

[includeIf "onbranch:master"]
    path=config.blame.inc
[includeIf "onbranch:REL_1{4,5,6,7,8,9}_STABLE"]
    path=config.blame.inc
[includeIf "onbranch:REL_2*_STABLE"]
    path=config.blame.inc

This is quite ugly, and it doesn't work at all if I run `git blame` in a
worktree that I create for development purposes (I don't name those
after the upstream PG branch they're based on).

Anybody has any idea how to handle this better?

A viable option would be to backpatch the addition of
.git-blame-ignore-revs to all live branches.  Would that bother anyone?

-- 
Álvaro Herrera        Breisgau, Deutschland  —  https://www.EnterpriseDB.com/