John Keeping [off-list ref] writes:

quoted

Here, "git pull . branch1" is merely saying "I want to integrate
the work on my current branch with that of branch1" without saying
how that integration wants to happen.

The change that I think is important is that the "bring my branch
up-to-date" operation should force the user to choose what to do if the
branch does not fast-forward to its upstream.  If that was spelled "git
update" then having "git pull" perform a merge would be fine, but we
spell this operation as "git pull" so the change needs to happen there.

I am not sure I quite get what you want to say with "git update",
and I am not sure if I necessarily want to know---I do not think we
would want to add yet another command that DWIMs for certain _I_,
that may not match newbie expectations.

I don't think "git pull remote branch" falls into the same category as
plain "git pull" so I'm not convinced that defaulting to merge there is
unreasonable.  The original message about this [1] did talk about only
"git pull" with no arguments.

If you want to limit the scope to only "git pull" (without any
command line argument), I actually do not have strong preference for
or against it either way.  Perhaps a follow-up patch to be squashed?