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

[Junio C Hamano <gitster@pobox.com>]

Junio C Hamano <gitster@pobox.com> writes:

> Mike Hommey <mh@glandium.org> writes:
>
>>> 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

s/this function (/this function is good (/;

> 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).