Re: "git checkout" resets modified files

From: Junio C Hamano <gitster@pobox.com>
Date: Aug 29, 2015, 07:15 UTC
Message-ID: <xmqqlhcuzhsu.fsf@gitster.mtv.corp.google.com>
In-Reply-To: <CANDob0LdQpoSfsedPK_yhNunXBvNTc9L1zKOM9h8dBUDePs0kg@mail.gmail.com>

Steve Heyns <notzippy@gmail.com> writes:

Show 13 quoted lines

> "git checkout" resets modified files
>
> Version git  2.5.0,
>
> Description:
> I was automating a process that would pull and switch to another
> branch when I stumbled across this. I have not been able to emulate
> this from command line but using go (or I imagine other languages are
> similar) if you execute a command like
>
> exec.Command("git","checkout","")
>
> A checkout with the branch parameter but the branch parameter is empty.

It is not feeding an empty branch parameter [*1*]. It is asking Git to check out all paths that match a pathspec "" out of the index.

Now, arguably, the user who would want to match everything may be more likely to give "." as the pathspec (or if she is not at the root of the working tree, ":/"), but "" means the same thing as ".", and the requested behaviour "check out all that match this pathspec from the index" would essentially mean "I want to get rid of all the modification in my working tree relative to the index".

I do not think this behaviour depends on the vintage of Git. An empty string as pathspec has always matched "everything in here" AFAIR.

[Footnote]

*1* Checking out a branch whose name is an empty string can be asked
    explicitly by disambiguating double-dash like this:

    $ git checkout "" --

And it will be answered (correctly) with:

    fatal: invalid reference