Re: [PATCH] fast-import: Do less work when given "from" matches current branch head

Mike Hommey [off-list ref] writes:

quoted

Does that mean the original code was doing a release that was
unnecessary?  Or does it mean this patch changes what happens on
that codepath, namely (1) leaking resource, and/or (2) keeping a
tree of the original 'b' that does not have anything to do with the
tree of 's', preventing the later lazy-load code from reading the
tree of 's' and instead of building on top of a wrong tree content?

I guess the question is whether branch_tree.tree can be in a state that
doesn't match that of branch_tree.versions[1].sha1. If not, then if s
and b have the same branch_tree.versions[1].sha1 for some reason, then
keeping the old branch_tree.tree makes no practical difference from
resetting it. Except it skips the busy-work.

Perhaps my comment was misleading.  I _think_ the state at the end
of this function (i.e. the latter hunk you added to the function
makes the above issue I raised go away).  It just made me feel
uneasy to leave branch_tree.tree and branch_tree.versions[] in an
inconsistent state inside this function, while it calls a few helper
functions (hence my comment on the fact that they do not seem to be
affected by this inconsistency).