Re: How to use git-svn to clone from a mirror?

David Kastrup [off-list ref] wrote:

Johannes Schindelin [off-list ref] writes:

quoted

On Mon, 4 Jun 2007, Raja R Harinath wrote:

quoted

David Kastrup [off-list ref] writes:

quoted

I have used something like

git-svn clone -T trunk -b branches -t tags file:///tmp/rsync-mirror

to clone an rsync mirror of an SVN repository.  Now I want to have 
fetch revert to pulling from the upstream repository in future. 
However, if I change the respective line in .git/config to 
svn://the.svn.link/whatever, git-rebase will fetch the right updates, 
but then says that it can't work with the objects in the git 
repository.

Changing the config back will make git-rebase -l work.

So what would be the right procedure to shift the SVN source from an
rsync mirror to the original, without git-svn breaking?

I think you'll have to

-------------8<------------
  # remove stored revision db, since we're going to change all the commit ids
  rm .git/svn/git-svn/.rev_db.*

  # rewrite git-svn-id: lines
  cg-admin-rewritehist \
	--msg-filter \
	'sed "s,file:///tmp/rsync-mirror,svn://the.svn.link/whatever,"'

  # recreate new revision db, and fetch updates, if any
  git-svn rebase
-------------8<------------

<shameless plug>
	Or you use the just-rewritten version of it, git-filter-branch.
</shameless>

Well, part of the reason I worked from an rsynced copy was to be able
to repeat the experiment by just wasting a few hours of time each
time, without wasting more bandwidth.

What I arrived at was to use
git-svn init -T trunk -t tags -b branches
  --rewrite-root svn://tug.org/texlive file:///mirror/texlive
git-svn fetch --all
[edit .git/config and replace the url and rewrite-root lines with a
 single url line pointing to the root]
git-reset --hard   [don't ask me why]
and afterwards fetches worked online.

Yes, sorry for the late response, but --rewrite-root was written
with this purpose in mind.

I liked the commit messages when using --no-metadata better than with
--rewrite-root, but I found no way to get the resulting archive
operative for git-svn rebase afterwards.

You should be able to use git-svn fetch and then plain git-rebase <remote>

Could someone explain to me why git needs to know the upstream URL
history, whether by --rewrite-root or rewrite-hist or
git-filter-branch?

I find this rather hard to understand, so I would like to get an idea
where this fits naturally into the overall design of git, and how it
makes sense.

Having the git-svn-id: lines in commits allows commits to be made to the
upstream SVN repository more easily and without user interaction or
configuraton.  I put git-svn-id: in the commit objects themselves
because they're immutable and robust.

The URL portion of git-svn-id: is useful when I'm using many throwaway
branches and I've forgotten which upstream (SVN) branch I need to
dcommit against, and git-svn can easily figure it out for me
without needing to remember to use git-checkout --track on my part
or memorization.

It's possible to clone the refs and objects over to a new repository
over the native git:// protocol and have it fully usable from git-svn
without needing additional setup or having to copy the .git/config or
.git/svn (neither of which are transferred over the git protocol).
Cloning the refs is a bit of a pain these days because of the "remotes/"
convention in the name, but still possible.

The .rev_db files in .git/svn can get corrupted or deleted, and since
they're not managed by git, they're next to impossible to recover
if the git-svn-id: lines didn't exist.

I'll be the first to admit that the git-svn-id: lines are ugly, but
that's why I wrote "git svn log" :)

-- 
Eric Wong