Re: Move to git is imminent - awaiting Stefan's approval

[Eli Zaretskii <eliz@gnu.org>]

> Date: Tue, 07 Jan 2014 11:24:12 +0100
> From: Angelo Graziosi <angelo.graziosi@alice.it>
> Cc: emacs <emacs-devel@gnu.org>
> 
> >> $ du -s emacs-trunk/
> >> 126M	emacs-trunk/
> >>
> >> instead the git repository has dimension
> >>
> >> $ du -s emacs.git/
> >> 1.1G	emacs.git/
> >
> > By default git downloads the history of all branches.  You can use
> > --single-branch to only clone a single branch.  This is the default if
> > you create a shallow clone.
> 
> David Kastrup wrote:
> 
> > For the build?  No.  git clone has the following options:
> >
> >         --depth <depth>
> ...
> > --[no-]single-branch
> ...
> 
> OK, trying
> 
> $ git clone --single-branch git://git.savannah.gnu.org/emacs.git emacs.git
> 
> the local repository has dimension 1.1G, so probably I need a more 
> explicit example...

The command you tried is correct, it's just that it doesn't save too
much disk space because the trunk has almost all of the revisions.

> Instead, trying
> 
> $ git clone --depth 1 git://git.savannah.gnu.org/emacs.git emacs.git
> 
> the local repository has dimension 160M which is a little greater than 
> my current BZR (checkout --lightweight) repository (126M), but acceptable...

This is not recommended at all, as such a shallow repository is
severely limited: you cannot clone from it, nor push from or to it.
You also have almost no history, and git does not support bzr-like
operation whereby commands in lightweight checkouts that need history
information go to the server.  So you will be unable to walk through
history and bisect.

> Suppose now I want identify which "revision" introduced a bug. I am able 
> to do this with a binary search using the BZR command
> 
> $ bzr up -r ARG
> 
> How can I do this with the "minimal" clone done with GIT?

You don't, see above.  With a full repository, or at least one that
was cloned with --single-branch, the equivalent of "bzr up" with git
is "git checkout", and the revision which you want is specified by
either is SHA1 signature or relatively, as in HEAD~20.