After reading PEP 384 and PEP 385 (finally) I got a strong impression that they are not ready for the change (read below the line for details), because they do not propose any workflow. So, instead of rushing with migration I'd like to propose incremental change rather than revolutionary that will allow people to taste what it like to work with Mercurial and update all relevant papers on the website. I propose to setup workflow that will include pulling changes to Mercurial master clone from current Subversion repository and pushing them back to Subversion using Mercurial. This will be similar to http://mercurial.selenic.com/wiki/DeveloperRepos scheme, but with hg-stable replaced with svn. I am willing to collaborate for getting this system in place before EuroPython even if I won't find a chance to get there. --- the line --- I didn' t have time to follow Mercurial discussion, so I expected PEP 384 and PEP 385 to be exhaustive reference on both the migration and workflow before and after the switch. Unfortunately, both are too vague in this respect and my opinion that migration now will do more harm than good. Primary concern is that will happen with central Subversion repository. There are a plenty of private tools and automated scripts that were written to work with central Subversion repository, so it is important that central Subversion repository continue to operate and be synchronized. However, PEP 385 "The Future of Subversion" [1] does not propose any way to keep Subversion repository in sync. "it will probably live on for a bit" phrase looks like Subversion will be immediately dead after switching. The second concern is workflow. Even after getting my hands dirty I still can't find the best solution for working with Mercurial copy of Python. In Subversion I do shallow checkouts of interesting features when I run into one bug or another. Not all patches are ready, so they stay in those checkouts as uncommitted diffs. To be prepared for conflicts I review code with `svn log -vr base:head` before updating. But with Mercurial I see two major problems with my workflow (which I am unlikely to change for the next few weeks due to heavy automation): 1. No shallow checkouts - that means that I have to copy 200Mb+ for every patch I have 2. No `hg log` command to see changes in my branch from remote repository before fetching them (I used to invoke `hg incoming`, but ended up with fetching everything with `hg pull` and then using `hg log -vr .:tip`, because `hg inc` didn't show changes that were already pulled, but not updated in wc, and `hg log` could not show incoming) 3. There is no clear branch separation in my working copy. I don't know how to diff files in different branches without copying 200Mb+ clone. I don't know how to diff my files with remote repository without pulling it. 4. Even if I make patch in my Mercurial clone - you still can't pull it and I have to attach it to tracker. No gain. So from these PEPs I can't really see how Mercurial solves problems with development. I can feel that it doesn't solve my problems, but I see no way where I can submit my user story. I would put accent on keeping mirror of Subversion as easy way to contribute for those who are not yet ready for DVCS. Subversion also provides greater interoperability. Assuming that any modern DVCS tool may act as Subversion client, we will gain more contributors if we won't try to force people use Python and Mercurial. [1] http://www.python.org/dev/peps/pep-0385/#the-future-of-subversion -- anatoly t.