From: Junio C Hamano <gitster@pobox.com>
Date: Tue, 24 Feb 2009 17:39:42 GMT
Subject: Re: [PATCHv2] Docs: Expand explanation of the use of + in git push refspecs.
Message-ID: <7veixnhgyp.fsf@gitster.siamese.dyndns.org>
In-Reply-To: <20090224165105.0FAE53360A6@rincewind>

Marc Branchaud <marcnarc@xiplink.com> writes:

> Signed-off-by: Marc Branchaud <marcnarc@xiplink.com>
> ---
>
> This version incorporates comments from Junio and Sverre.
>
>  Documentation/git-push.txt |   36 +++++++++++++++++++++++++++++++-----
>  1 files changed, 31 insertions(+), 5 deletions(-)

Nice.

Looks much more readable than before, especially with a picture.

Thanks.

> diff --git a/Documentation/git-push.txt b/Documentation/git-push.txt
> index 7d1eced..2fae4fd 100644
> --- a/Documentation/git-push.txt
> +++ b/Documentation/git-push.txt
> @@ -48,17 +48,19 @@ push. Arbitrary expressions cannot be used here, an actual ref must
>  be named. If `:`<dst> is omitted, the same ref as <src> will be
>  updated.
>  +
> -The object referenced by <src> is used to fast forward the ref <dst>
> -on the remote side. If the optional leading plus `{plus}` is used, the
> -remote ref is updated even if it does not result in a fast forward
> -update.
> +The object referenced by <src> is used to update the <dst> reference
> +on the remote side, but by default this is only allowed if the
> +update can fast forward <dst>.  By having the optional leading `{plus}`,
> +you can tell git to update the <dst> ref even when the update is not a
> +fast forward.  This does *not* attempt to merge <src> into <dst>.  See
> +EXAMPLES below for details.
>  +
>  `tag <tag>` means the same as `refs/tags/<tag>:refs/tags/<tag>`.
>  +
>  Pushing an empty <src> allows you to delete the <dst> ref from
>  the remote repository.
>  +
> -The special refspec `:` (or `+:` to allow non-fast forward updates)
> +The special refspec `:` (or `{plus}:` to allow non-fast forward updates)
>  directs git to push "matching" branches: for every branch that exists on
>  the local side, the remote side is updated if a branch of the same name
>  already exists on the remote side.  This is the default operation mode
> @@ -218,6 +220,30 @@ git push origin :experimental::
>  	Find a ref that matches `experimental` in the `origin` repository
>  	(e.g. `refs/heads/experimental`), and delete it.
>  
> +git push origin {plus}dev:master::
> +	Update the origin repository's master branch with the dev branch,
> +	allowing non-fast forward updates.  *This can leave unreferenced
> +	commits dangling in the origin repository.*  Consider the
> +	following situation, where a fast forward is not possible:
> ++
> +----
> +	    o---o---o---A---B  origin/master
> +	             \
> +	              X---Y---Z  dev
> +----
> ++
> +The above command would change the origin repository to
> ++
> +----
> +	              A---B  (unnamed branch)
> +	             /
> +	    o---o---o---X---Y---Z  master
> +----
> ++
> +Commits A and B would no longer belong to a branch with a symbolic name,
> +and so would be unreachable.  As such, these commits would be removed by
> +a `git gc` command on the origin repository.
> +
>  
>  Author
>  ------
> -- 
> 1.6.1.2.390.gba743