threads / discuss / 22528

Re: creating a new branch without an ancestor

Subject: Re: creating a new branch without an ancestor

## tl;dr

4 messages between Feb 5, 2010 and Feb 5, 2010.

replies: 3people: 4as markdown or json

Michael Wookey· Feb 5, 2010, 03:19 UTC · lore

creating a new branch without an ancestor

Maybe I'm missing something from reading the docs, but I couldn't see how to create a new branch in an existing repo that has no ancestor. I would like to do something like what git.git does with some of the other ancillary branches like "man", "html", and "todo".

I was hoping to do something like "git branch --no-ancestor new-branch-name" but didn't see anything in the documentation that describes the necessary branch options.

Or, am I looking in the wrong place?
Larry D'Anna· Feb 5, 2010, 03:24 UTC · re: Michael Wookey · lore
* Michael Wookey (michaelwookey@gmail.com) [100204 22:20]:
Show 10 quoted lines
> Maybe I'm missing something from reading the docs, but I couldn't see
> how to create a new branch in an existing repo that has no ancestor. I
> would like to do something like what git.git does with some of the
> other ancillary branches like "man", "html", and "todo".
> 
> I was hoping to do something like "git branch --no-ancestor
> new-branch-name" but didn't see anything in the documentation that
> describes the necessary branch options.
> 
> Or, am I looking in the wrong place?
git symbolic-ref HEAD refs/heads/whatever

That'll leave your index and working tree alone of course, so if you did a commit right after that it would match the content of your current branch but not the history.

    --larry
Jay Soffian· Feb 5, 2010, 03:32 UTC · re: Larry D'Anna · lore
On Thu, Feb 4, 2010 at 10:24 PM, Larry D'Anna <larry@elder-gods.org> wrote:
Show 17 quoted lines
> * Michael Wookey (michaelwookey@gmail.com) [100204 22:20]:
>> Maybe I'm missing something from reading the docs, but I couldn't see
>> how to create a new branch in an existing repo that has no ancestor. I
>> would like to do something like what git.git does with some of the
>> other ancillary branches like "man", "html", and "todo".
>>
>> I was hoping to do something like "git branch --no-ancestor
>> new-branch-name" but didn't see anything in the documentation that
>> describes the necessary branch options.
>>
>> Or, am I looking in the wrong place?
>
> git symbolic-ref HEAD refs/heads/whatever
>
> That'll leave your index and working tree alone of course, so if you did a
> commit right after that it would match the content of your current branch but
> not the history.

You can also create the branch in a new repo, then just fetch that into your existing repo.

j.
Wesley J. Landaker· Feb 5, 2010, 18:38 UTC · re: Michael Wookey · lore
On Thu, February 4, 2010 20:19, Michael Wookey wrote:
Show 10 quoted lines
> Maybe I'm missing something from reading the docs, but I couldn't see
> how to create a new branch in an existing repo that has no ancestor. I
> would like to do something like what git.git does with some of the
> other ancillary branches like "man", "html", and "todo".
>
> I was hoping to do something like "git branch --no-ancestor
> new-branch-name" but didn't see anything in the documentation that
> describes the necessary branch options.
>
> Or, am I looking in the wrong place?

I do this all the time for various reasons, so I made myself a "git-emptybranch" command and stuck it in my path. Besides the error checking, this just creates a new ref and clears the index so you can start from a clean slate. No actual files are deleted from the work-tree.

$ cat ~/bin/git-emptybranch
#!/bin/sh
if [ $# -ne 1 ]; then
  2<&1
  echo "usage: git emptybranch <new_branch>"
  exit 1
fi
if ! git check-ref-format refs/heads/"$1"; then
  2<&1
  echo "fatal: '$1' is not a valid branch name."
  exit 1
fi

git symbolic-ref -m "git emptybranch $1" HEAD refs/heads/"$1" git rm --cached -r -q --ignore-unmatch -- '*'

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