Migrating from SVN to DVCS.

[Jelmer Vernooij]

On Thu, Jun 14, 2012 at 12:01:27PM +1000, Philip Peitsch wrote:
> On 14 June 2012 08:46, Jelmer Vernooij <jelmer at samba.org> wrote:
> 
> > On Thu, Jun 07, 2012 at 09:46:14PM +1000, Philip Peitsch wrote:
> > > I've been using bzr+svn at my company since late 2010 with a decent
> > amount
> > > of success. It works as advertised for inter-bazaar trading, and works
> > > generally well for bzr-svn.
> >
> > > Some rather important bugs to watch for:
> >
> > >    - https://bugs.launchpad.net/bzr/+bug/485601
> > >    - https://bugs.launchpad.net/bugs/887880
> > >    - https://bugs.launchpad.net/bzr-svn/+bug/628354
> >
> > Note that these aren't relevant when just importing from Subversion
> > into Bazaar; they are related to the metadata pushed by bzr-svn,
> > they can only occur with repositories that you have pushed to with
> > older versions of bzr-svn.
> >
> >
> Daniel's questioning seems to be around allowing continued use of both
> subversion (for those not willing to migrate) and bazaar in tandem on the
> same trunk? *If* my assumption is correct, then his workflow does fall into
> the same area of risk that mine has here.
> 
> The largest challenge is that to correctly "fix" the svn repo & process
> after one of these listed defects occur, one needs to:
> 
>    1. Get all developers with access to the branch (~30 in two large
>    buildings) to uninstall Bazaar
>    2. Reset all svn revprops related to Bazaar
>    3. Get all developers to remove the bzr-svn cache and all local bazaar
>    repositories that have ever contained the corrupted svn repository, or
>    bazaar branches directly related to these (basically, devs should remove
>    all local repositories...)
>    4. Get all developers to install the latest version of bazaar
>    5. Rebranch / re-setup all repositories
> 
> It basically requires freezing a full development team for 2 working days
> to enact fully (doing a checkout of our current trunk takes 3-4hrs I
> believe).  And, if any developer misses even one of their required cleanup
> steps, the whole subversion repository becomes unusuable again as soon as
> they accidentally commit, due to
> https://bugs.launchpad.net/bzr-svn/+bug/628354.
> 
> The other challenge is that all troubleshooting steps generally turn the
> shared repository into a read-only system for several hours (e.g., bzr
> check & reconcile).
A check and reconcile shouldn't be necessary, just a new import of the
svn repository into bzr. reconcile doesn't fix the issues you were
hitting.

> To restate though, we are happily using Bazaar in a specific workflow. The
> listed issues are more to highlight the style of problems that have
> occurred in the past and *may* still be in the system.
I'm interested to hear about issues that haven't been fixed yet; there
aren't any bugs in the bug tracker with sufficient information with
recent versions of bzr-svn.

Cheers,

Jelmer