Re: [PATCH 2/2 v3] sha1_name: teach get_sha1_1 "-" shorthand for "@{-1}"

Matthieu Moy [off-list ref] writes:

Siddharth Kannan [off-list ref] writes:

quoted

+	if (!strcmp(name, "-")) {
+		name = "@{-1}";
+		len = 5;
+	}

One drawback of this approach is that further error messages will be
given from the "@{-1}" string that the user never typed.

Right.

There are at least:

$ git grep -n -A1 'strcmp.*"-"' | grep -B 1 '@\{1\}'
builtin/checkout.c:975: if (!strcmp(arg, "-"))
builtin/checkout.c-976-         arg = "@{-1}";

I didn't check the surrounding context to be sure, but I think this
"- to @{-1}" conversion cannot be delegated down to revision parsing
that eventually wants to return a 40-hex as the result.  

We do want a branch _name_ sometimes when we say "@{-1}"; "checkout
master" (i.e. checkout by name) and "checkout master^0" (i.e. the
same commit object, but not by name) do different things.

builtin/merge.c:1231:   } else if (argc == 1 && !strcmp(argv[0], "-")) {
builtin/merge.c-1232-           argv[0] = "@{-1}";
--
builtin/revert.c:158:           if (!strcmp(argv[1], "-"))
builtin/revert.c-159-                   argv[1] = "@{-1}";

These should be safe to delegate down.

builtin/worktree.c:344: if (!strcmp(branch, "-"))
builtin/worktree.c-345-         branch = "@{-1}";

I do not know about this one, but it smells like a branch name that
wants to be used before it gets turned into 40-hex.