Is the entire working copy “at one branch”?

This is a very basic question but maybe I just don't know how to phrase my query well enough to find an answer.

Let me begin with a SVN example. SVN doesn't have a "current branch" as a property of a working copy, so I'll give the example with revisions instead. Consider a working copy with the dirs `foo` and `bar` in it. In SVN one can `update` foo to an earlier version, but keep `bar` at `HEAD`.

Is it possible in an analogical git working copy to checkout one branch in dir `foo` without changing the branch checked out in `bar`?

If not, why not?

TIA, Stefan Monov

Hi Stefan,

Generally with git, your entire working copy will have the same revision (set to current branch, aka HEAD). The idea behind this is that your working copy of a repository should always be in consistent state.

You can check out specific files or directories from another revision (mimicking "svn update -r1234 filename"):

    $ git checkout branch-or-sha-hash -- filename

However, SVN tracks the 'revision' thing on per-file basis, while in git this is a property of the working copy. So if you do like above then git will be telling you that the 'filename' has been changed (as it is certainly different from its pristine version in HEAD):

    $ git status
    On branch master
    Changes to be committed:
      (use "git reset HEAD <file>..." to unstage)

            modified:   filename

So it's generally not recommended to do such a thing.

Another thing that you _can do_ in git to mimick SVN is the 'standard layout'. There is a feature called "git worktree" which allows you to have SVN-like directory structure with multiple directories linked to different working copies:

    $ mkdir my-project
    $ cd my-project
    $ git clone my-project-repository master
    $ mkdir branches
    $ cd master
    $ git worktree add -b branch-1 ../branches/branch-1
    $ git worktree add -b branch-2 ../branches/branch-2

After that you will have directory structure like this:

    $ tree my-project
    my-project
    ├── branches
    │   ├── branch-1
    │   │   ├── 1
    │   │   ├── 2
    │   │   └── 3
    │   └── branch-2
    │       ├── 1
    │       ├── 2
    │       └── banana
    └── master
        ├── 1
        └── 2
You can work with these working copies separately, like you
would be working with SVN. Commits in 'master' will go to the
'master' branch, commits made in 'branches/branch-1' will go
to the 'branch-1' branch.

Thanks Alexei!

On Sat, Oct 29, 2016 at 12:47 PM, Alexei Lozovsky <a.lozovsky@gmail.com> wrote: