Re: [PATCH] setup: tweak upgrade policy to grandfather worktreeconfig

Jonathan Nieder [off-list ref] writes:

It's too late to go that far for 2.28.  It would be tempting to try a
simple revert of 14c7fa269e4 (check_repository_format_gently(): refuse
extensions for old repositories, 2020-06-05) to get back to tried and
true behavior but that does not do enough --- it still produces an
error when trying to upgrade repository format when any extensions are
set.  So how about such a revert plus Junio's patch plus the analogous
change to Junio's patch for

  extensions.preciousObjects
  extensions.partialClone

My illustration patch was done "assuming that worktreeconfig is the
only thing we wrote by mistake without updating the format version",
and if these two also share the same problem, I obviously is 100%
fine with covering these other ones with the same approach.

I like your "v0 and v1 are the same, but the repository is declared
to be corrupt if the extentions that are not known by today's code
is found in v0 repository", by the way.  Assuming that the two you
listed above plus worktreeconfig are the only ones known by today's
code, that is.  We seem to also know about "noop", so shouldn't it
also be grandfathered in?