What is the default refspec for fetch?

What is the default refspec for fetch?

[Christian Halstrick]

Hi,

In a repo where no remote.<name>.fetch config parameter is set what
should a "git fetch" do? My experiments let me think it's
"HEAD:FETCH_HEAD". Right?

I came to this question after finding out that when I clone repos in
bare mode then they don't have and explicit remote.<name>.fetch in
their config. But a "git fetch" sometimes updated "something".

Ciao
  Chris

Re: What is the default refspec for fetch?

[Jeff King]

On Fri, Nov 07, 2014 at 04:31:08PM +0100, Christian Halstrick wrote:

> In a repo where no remote.<name>.fetch config parameter is set what
> should a "git fetch" do? My experiments let me think it's
> "HEAD:FETCH_HEAD". Right?

Basically, yes. We always write FETCH_HEAD, regardless of the refspec.
We choose "HEAD" if no other refspec was provided. So it is really more
like

  git fetch $remote HEAD

This is what makes one-off bare-url pulls work, like:

  git pull git://...

It runs fetch under the hood, which writes into FETCH_HEAD, and then we
merge that.

-Peff

Re: What is the default refspec for fetch?

[Jakub Narębski]

W dniu 2014-11-08 11:52, Jeff King pisze:
> On Fri, Nov 07, 2014 at 04:31:08PM +0100, Christian Halstrick wrote:
>
>> In a repo where no remote.<name>.fetch config parameter is set what
>> should a "git fetch" do? My experiments let me think it's
>> "HEAD:FETCH_HEAD". Right?
>
> Basically, yes. We always write FETCH_HEAD, regardless of the refspec.
> We choose "HEAD" if no other refspec was provided. So it is really more
> like
>
>    git fetch $remote HEAD
>
> This is what makes one-off bare-url pulls work, like:
>
>    git pull git://...
>
> It runs fetch under the hood, which writes into FETCH_HEAD, and then we
> merge that.

Actually FETCH_HEAD consists of multiple lines, one per ref...
but only top ref is merged.

-- 
Jakub Narębski

Re: What is the default refspec for fetch?

[Junio C Hamano]

Jakub Narębski <jnareb@gmail.com> writes:

> W dniu 2014-11-08 11:52, Jeff King pisze:
>> On Fri, Nov 07, 2014 at 04:31:08PM +0100, Christian Halstrick wrote:
>>
>>> In a repo where no remote.<name>.fetch config parameter is set what
>>> should a "git fetch" do? My experiments let me think it's
>>> "HEAD:FETCH_HEAD". Right?
>>
>> Basically, yes. We always write FETCH_HEAD, regardless of the refspec.
>> We choose "HEAD" if no other refspec was provided. So it is really more
>> like
>>
>>    git fetch $remote HEAD
>>
>> This is what makes one-off bare-url pulls work, like:
>>
>>    git pull git://...
>>
>> It runs fetch under the hood, which writes into FETCH_HEAD, and then we
>> merge that.
>
> Actually FETCH_HEAD consists of multiple lines, one per ref...
> but only top ref is merged.

Incorrect in that "only top" is misinformation, and irrelevant in
the context of discussing the "what is fetched in a one-off fetch".

Re: What is the default refspec for fetch?

[Christian Halstrick]

ok, thanks. Then I'll teach JGit to fetch at least "HEAD" if nothing
is configured and nothing explicitly specified as refspec.
Ciao
  Chris


On Sun, Nov 9, 2014 at 6:23 PM, Junio C Hamano <gitster@pobox.com> wrote:
> Jakub Narębski <jnareb@gmail.com> writes:
>
>> W dniu 2014-11-08 11:52, Jeff King pisze:
>>> On Fri, Nov 07, 2014 at 04:31:08PM +0100, Christian Halstrick wrote:
>>>
>>>> In a repo where no remote.<name>.fetch config parameter is set what
>>>> should a "git fetch" do? My experiments let me think it's
>>>> "HEAD:FETCH_HEAD". Right?
>>>
>>> Basically, yes. We always write FETCH_HEAD, regardless of the refspec.
>>> We choose "HEAD" if no other refspec was provided. So it is really more
>>> like
>>>
>>>    git fetch $remote HEAD
>>>
>>> This is what makes one-off bare-url pulls work, like:
>>>
>>>    git pull git://...
>>>
>>> It runs fetch under the hood, which writes into FETCH_HEAD, and then we
>>> merge that.
>>
>> Actually FETCH_HEAD consists of multiple lines, one per ref...
>> but only top ref is merged.
>
> Incorrect in that "only top" is misinformation, and irrelevant in
> the context of discussing the "what is fetched in a one-off fetch".

Re: What is the default refspec for fetch?

[Junio C Hamano]

Christian Halstrick <christian.halstrick@gmail.com> writes:

> ok, thanks. Then I'll teach JGit to fetch at least "HEAD" if nothing
> is configured and nothing explicitly specified as refspec.

Sounds like a sensible thing to do to match what JGit does to what
we did from the time immemorial ;-)

Thanks.