On Mon, Aug 8, 2022 at 4:47 PM Junio C Hamano[off-list ref]  wrote:

The "-d" and "-D" options being the more detructive ones among other
operation modes of the command, I am not sure if this change is even
desirable.  Even if it were, the implementation to special case a
single argument case like this ...

quoted

+     if ((argc == 1) && !strcmp(argv[0], "-")) {
+             argv[0] = "@{-1}";
+     }

... (by the way, we don't write braces around a single statement
block) would invite cries from confused users why none of these ...

  $ git branch -m - new-name
  $ git branch new-branch -
  $ git branch --set-upstream-to=<upstream> -

work and "-" works only for deletion.

Agree. But the approach is to ease the deletion of previous branch,
aligned with merge:

$ git merge - -
merge: - - not something we can merge
$ git merge - old-branch
merge: - - not something we can merge

In fact, I think it is a bit confuse to allow use it that way, and
probably induces to error.

Haven't think about -m, -c. If you think it is a good addition, I can do it.

I can fix the braces around that single statement block, sorry.