Junio C Hamano <gitster@xxxxxxxxx> writes:
> Matthieu Moy <Matthieu.Moy@xxxxxxxxxxxxxxx> writes:
>
>> Siddharth Kannan <kannan.siddharth12@xxxxxxxxx> writes:
>>
>>> + 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.
FYI, the "@{-<number>} to branch name" translation happens in
interpret_branch_name(). I do not offhand recall if any callers
protect their calls to the function with conditionals that assume
the thing must begin with "@{" or cannot begin with "-" (the latter
of which is similar to the topic of patch 1/2 of this series), but I
suspect that teaching the function that "-" means the same as
"@{-1}" would bring us closer to where we want to go.