Hi Junio
On 01/10/2021 22:08, Junio C Hamano wrote:
"Phillip Wood via GitGitGadget" <gitgitgadget@xxxxxxxxx> writes:
From: Phillip Wood <phillip.wood@xxxxxxxxxxxxx>
This parameter is only needed when a ref is going to be updated and
the caller does not pass an explicit reflog message. Callers that are
just discarding changes in the working tree like create_autostash() do
not update any refs so should not have to worry about passing this
parameter.
This only talks about internal implementation details of passing a
parameter that may not be used, but ...
- ret = update_refs(oid, switch_to_branch, reflog_head, reflog_orig_head,
- default_reflog_action, flags);
+ if (oid != &head_oid || update_orig_head || switch_to_branch)
+ ret = update_refs(oid, switch_to_branch, reflog_head,
+ reflog_orig_head, default_reflog_action,
+ flags);
... doesn't this have a more significant behaviour change?
I am not sure if comparison between oid and head_oid can safely
cheat like the patch does, or if it is necessary to do a proper oid > comparison, but either way, this would stop calling update_refs(),
which in turn means it would have an externally visible effect, like
a hook no longer getting called, doesn't it?
It would be a change for the good---calling post-checkout hook when
you did "git checkout (no other arguments)" feels wasteful, but it
deserves to be told to end users, I would think.
That would be a change for the good, but it is not what this patch does.
If oid == &head_oid then it means that the caller did not give us a tree
to checkout so HEAD will not change unless we are switching branches.
Using a pointer comparison rather than calling oidcmp() was a deliberate
choice to avoid any user visible changes as there are no callers that
try to run the checkout-hook without passing an oid or branch. The aim
here is to avoid having to pass default_reflog when it is not needed
without making any user visible changes.
Again, a new test to protect the change would go well in the same
patch.
I'm not sure what we could test
Best Wishes
Phillip
Thanks.
