Ability to edit local copies of remote branches-CodePudding

I have difficulty understanding/verifying the following line from Pro Git:

It’s important to note that when you do a fetch that brings down new remote-tracking branches, you don’t automatically have local, editable copies of them. In other words, in this case, you don’t have a new serverfix branch — you have only an origin/serverfix pointer that you can’t modify.

I tried the following for a repository.

git clone git://git.bugseng.com/ppl/ppl.git
cd ppl

I removed folder ppl/src/ from my local machine, and made a copy of pre-existing folder ppl/m4/ into ppl/m4 - Copy just so as to locally modify/edit this folder a bit.

Then, I ran git fetch origin just to (I thought) set myself up to be in the situation mentioned in the book's quote above. I (of course) do not have any write access to this online repository.

Now, I am easily able to do git add . and git commit without any errors. Output of git status is:

:~/ppl$ git status
On branch master
Your branch is ahead of 'origin/master' by 1 commit.

all as expected. That is, I have been able to make a commit and edit the branch locally. I am unable to reconcile this with the quote from the book which states that I would not have local editable copies of them.

CodePudding user response：

Notice that the phrases you quoted refer to a serverfix branch — not to master.

In the case of master (or whatever the remote HEAD is), when you clone you are given a local copy automatically; thus there was no need for you to make one.

But if there had been any other branches, clone does not make local copies of those for you, and a mere fetch would not have given you local copies of them either. You might have remote-tracking branches such as origin/someBranch, but if you wanted to edit someBranch, you'd have to create it first.

CodePudding user response：

The Pro Git reference is saying that a git fetch does not actually checkout a local copy of the remote branch you have fetched. It is merely a pointer to allow git locally to know the branch exists and allow you to check it out. To test this, clone a copy of your remote repository. Next create a branch on your remote fetch-branch-test. Run git checkout fetch-branch-test on your local repo, and you will get an error saying git can't find the branch. Run git fetch locally, then git branch. You will see that there is still no local copy of fetch-branch-test. Finally, run git checkout fetch-branch-test again, and you will notice you now have a local copy of the remote branch. This is because git fetch added a local pointer of the new remote branch, but did not add a local copy of it until you ran git checkout.