This is an old revision of the document!
Description
It should be possible to import the current FreeBSD CVS repository, and retain the following.
- A complete history of HEAD
- Every RELENG branch, mapped to the appropriate branching methodology of the target VCS
- If the target VCS supports atomic commits then commits to the CVS repo that would have been considered atomic by log_accum.pl should also be atomic in the new repository
It is not necessary to maintain the same per-file revision numbers. However, it is desirable that a mechanism be available to map from commits in the new repo to commits in CVS.
For example, it should be possible to say that src/README, r1.23, can be found at revision N (or changeset FOO) in the new repo.
Current Implementation
N/A
SVN Implementation
Hg Implementation
Git Implementation
Git's conversion-from-CVS tools are still a work in progress. There are a few options:
git-cvsimport
This should be ignored. It uses cvsps, which totally mangles your history
parsecvs
This tool does a good job of mapping CVS history into atomic commits. However, the current algorithm is O(revisions * files) in memory, which is too much on repos of our size (died on an i386 with 3GB of RAM). We think we can get it down to O(revisions + files) or so, which should be doable.
cvs2svn; git-fast-import (or cvs2svn ; svn2git)
The problem here is that there have been many reports of cvs2svn getting the history wrong. One of the features of parsecvs is that I understand its methods, and its methods sound pretty solid. Also, the cvs2svn conversions are quite time-consuming (several days on mozilla, from what I understand, which is about twice our size), so doing repeated imports to get a sample repository output that you like is rough.
Monotone Implementation
Partially Supported (also see the [http://venge.net/monotone/wiki/FeatureCVSImport related page on Monotone wiki])
Monotone can import cvs history, including collecting together changes in multiple files into synthesised change sets. The cvs_import command provides this feature; this is just one of several ways of working with Monotone and CVS.
The primary limitation is that CVS branches are presently not attached to the revisions they branched off from: each is an independent linear history. Work is underway to resolve this limitation.