Git Rebase Issue
- From
- Pierre-Luc Loyer <pierre-luc.loyer@bhvr.com>
- Date
- Dec 22, 2015, 17:53 UTC
- Message-ID
- <39E7EE9D306F544FAD3A0D16B7B7CAAD2C1E819D@mtlsvrmxwv02.A2M.com>
Hi,
I've encountered a situation using rebase for which I don't understand the results, even after reading the documentation. I'm currently working in my feature branch and then I want to squash commits, thus I use interactive rebase. After successfully completing the rebase, I end up in a detached HEAD state, rather than back on my branch, which is confusing. The command that is causing me to be in detached HEAD mode is: git rebase -i HEAD~2 HEAD From the documentation, I read that my second parameter (HEAD) is the <branch> parameter:
git rebase [-i | --interactive] [options] [--exec <cmd>] [--onto <newbase>]
[<upstream>] [<branch>]
If <branch> is specified, git rebase will perform an automatic git checkout <branch> before doing anything else. Otherwise it remains on the current branch. <branch> Working branch; defaults to HEAD.
Upon completion, <branch> will be the current branch.
Here is a full example than can be used to easily repro the issue. Go to an empty folder. git init git echo text > file.txt git add . git commit -m "Add file.txt" git echo text2 > file.txt git commit -am "Modify file.txt" git echo text3 > file.txt git commit -am "Remodify file.txt"
Now the interesting part: $ git rebase -i HEAD~2 HEAD [detached HEAD 9178b93] Modify file 1 file changed, 1 insertion(+), 1 deletion(-) Successfully rebased and updated detached HEAD.
From the documentation it says that <branch> (which is HEAD) will be checked out before doing anything and that upon completion, <branch> will be the current branch. However, this doesn't seem to happen. In fact, it seems more like the following is happening during the rebase: 1) detach HEAD 2) rebase 3) reattach to <branch>
If <branch> is HEAD, then is does nothing and remains detached. I find this behavior confusing since I would expect it to return to whatever HEAD was pointing to at the start of the command, such as my branch. Also, the documentation says that the <branch> parameter defaults to HEAD, so passing 'HEAD' explicitly should result in the same behavior as not passing it: <branch> Working branch; defaults to HEAD.
Pierre-Luc Loyer