# git refusing to merge branches when pulling using a refspec

2 messages from 2023-11-06 to 2023-11-06. Participants: Santiago García Pimentel, Junio C Hamano.
Thread: https://gitlist.dev/t/60480

## Santiago García Pimentel, 2023-11-06 17:36

Subject: git refusing to merge branches when pulling using a refspec
Message-ID: <FC0625CD-D736-412C-A4C5-04F9F41FFEEA@garciapimentel.com>
URL: https://gitlist.dev/e/FC0625CD-D736-412C-A4C5-04F9F41FFEEA%40garciapimentel.com

```
Hello,

I'm dealing with a small automation (CI) to synchronise some specific branches between two git repositories.

I need to sync a branch with other using a user-given refspec. e.g.

$ git pull origin "refs/heads/branchOrigin:refs/heads/branchDestination”.

(I’ll have a list of refspecs, but so far Im trying to make it work with one)

When the branch can be fast-forwarded there is no problem, but I cannot manage to make it work when it cant.

I just. get the message "[rejected] branchOrigin -> branchDestination (non-fast forward)."

I've tried  the following:
- adding a git config with pull.rebase=false  (I also tried true)
- adding --no-rebase to the pull command  (I also tried —rebase)

In any cases the result is the same

The issue is, It does work if I just pass the branch names. e.g.

git pull origin branchOrigin --no-edit

merges the branch just fine

Im not sure why git refuses to merge the branches when I pass a full refspec. is this intentional? is there some other incantation I need to use to make this work?

Thank you!

Santiago García Pimentel.
santiago@garciapimentel.com
```

## Junio C Hamano, 2023-11-06 23:38

Subject: Re: git refusing to merge branches when pulling using a refspec
Message-ID: <xmqqbkc6cv07.fsf@gitster.g>
URL: https://gitlist.dev/e/xmqqbkc6cv07.fsf%40gitster.g
In-Reply-To: <FC0625CD-D736-412C-A4C5-04F9F41FFEEA@garciapimentel.com>

```
Santiago García Pimentel <santiago@garciapimentel.com> writes:

> Hello,
>
> I'm dealing with a small automation (CI) to synchronise some specific branches between two git repositories.
>
> I need to sync a branch with other using a user-given refspec. e.g.
>
> $ git pull origin "refs/heads/branchOrigin:refs/heads/branchDestination”.
>
> (I’ll have a list of refspecs, but so far Im trying to make it work with one)
>
> When the branch can be fast-forwarded there is no problem, but I cannot manage to make it work when it cant.
>
> I just. get the message "[rejected] branchOrigin -> branchDestination (non-fast forward)."
With the "pull" command above, you are doing two logically
independent things.  Do you really need to do both?

 * git pull "<remote>" "<src>:<dst>" first does a "git fetch" to
   locally update <dst> with the commit that is pointed at by <src>
   at the <remote> repository.

 * then, into the currently checked out HEAD, the <src> taken from
   <remote> is merged into.

If you do not need to update <dst> locally, don't give :<dst> part
on the command line.

If you do need to update <dst> locally and safely, then thank that
you got the [rejected] message.  Because the <src> was updated at
the <remote> side that is not based on what you have at <dst>
locally, you may be losint commits from your local <dst> if you let
the first stage of the "git pull" go through, and that is what the
failing command is about.

If you do need to update <dst> locally but you do not have anything
valuable on <dst> locally (in other words, <dst> is used only to
keep track of <src> at <remote>, and if <remote> rewinds the history
of their <src> and loses some commits, you want to lose these commits
the same way from your <dst>), then add "+" before the refspec, i.e.

    git pull "<remote>" "+<src>:<dst>"


```