Your first option should probably be the ConvertExtension bundled with Mercurial. It supports branches, incremental imports, and a few other nice features, and is maintained by the Mercurial authors. It currently only understands CVS, Subversion, Git, Darcs, Monotone, Bazaar, GNU Arch, Perforce and Mercurial as source formats and Mercurial and Subversion as destination formats.
Otherwise, the following tools may be useful.
1. Arch / TLA / Baz 1.5
The ConvertExtension supports GNU Arch since (df659eb23360, 0.9.5+)
Other tools for Arch conversion can be found at ArchConversion.
ClearCaseConversion - some ideas
Convert to CVS (see ConvertExtension#Converting_from_RCS) and then use CVS tools.
Multiple convertors exist for converting from CVS to Mercurial:
ConvertExtension - the convert extension supports simple CVS repositories
Tailor - a generic conversion tool
fromcvs - a fast, incremental CVS to Mercurial converter
Note: Mercurial's ConvertExtension uses a naive algorithm to understand CVS. If your CVS repository contains no tags and no branches, it'll work just fine. If you, and everyone who has ever used your CVS repository, have always tagged/branched the tip of your entire source tree, it should work just fine. But if you have ever played any funny games with tagging or branching, ConvertExtension will not work. It doesn't even try to handle those cases because it is based on cvs2ps, which doesn't even try to understand the full range of strange things people do with CVS tags/branches. The only tool known to handle all of CVS' weird corner cases is cvs2svn. Luckily, there is now a version of cvs2svn with a native Mercurial backend called cvs2hg. See its README.cvs2hg file for more information. However cvs2hg may generate 'fixup commits' that violate the invariant that parents of a merge changeset shall not be linearly related. This means that subsequent operations on the converted repository will silently fail.
In the past, other options have included:
use cvs2svn to convert to Subversion, then ConvertExtension to import the Subversion repository.
use cvs2git to convert to git fast-import format, then use FastImportExtension to import that.
You can also convert from Mercurial to CVS:
CvscommitExtension - (need info)
The ConvertExtension supports Darcs.
- An older sample Darcs conversion script is available in the contrib/ directory of the Mercurial source.
Also see Tailor.
See GitConversion (incremental).
The ConvertExtension included in Mercurial 0.9.5 can import Subversion trees. It uses the Subversion API, so it can speak any Subversion repository access protocol. It's a good idea to work against a local copy of the Subversion repository you want to convert. Make a local copy of your svn repo using svnsync.
Examples and details about Subversion interoperability can be found in WorkingWithSubversion.
Converters that work on local repositories or data (faster, if this is an option for you):
http://hg.omnifarious.org/~hopper/svn2hg - requires python2.5 and is very rough, lacking in documentation or any UI niceties at all to speak of.
Converters that work on remote repositories:
http://ajayu.memi.umss.edu.bo/viborita/weblog/svn2hg.py-convertir-repositorio-subversion-mercurial - simple script that downloads every rev info from svn server. Works on subdirectories of the repo. Handles branches, tags, etc. inefficiently (does not tell hg that they are different from any other diff). Requires pysvn, Mercurial source. Use the download link, not copy&paste.
http://dingoskidneys.com/cgi-bin/hgwebdir.cgi/queue-convert-svn/ - Patch queue against Mercurial. Patches create a convert-repo hacked to support SVN as a source. Uses the SVN API, not SVN command line + subprocess.
hgsvn allows you to work on SVN checkouts using Mercurial (mirroring all SVN history in a local Mercurial repository on which you can also do local development). It is useful for managing private branches, submitting patches to project maintainers, have fast local operations instead of slow remote "svn up/log/blame", etc. Also useful as "one-shot" conversion tool if you just remove all the svn directories ("find . -name '.svn' |xargs rm -r") afterwards.
SubversionToMercurialSync (like hgsvn, but more primitive)
The HgSubversion Mercurial extension. Read about it in its own page on this wiki.
The ConvertExtension supports conversion from Perforce since version 1.2.
The Perfarce extension allows you to pull changelists from Perforce, and to push Mercurial changesets back to it.
There is also a stand-alone script p4_to_hg This utility can actually keep two repositories in sync.
Currently, it's slapped together and built to serve my particular needs, but it could probably be modified into something more general. It currently makes no attempt to do anything with Perforce's ability to track branches or the movement of changesets from branch to branch. But it hasn't received any love since 2007 or so, and I don't have access to a Perforce repository to use anymore, so I'm not doing any development on it. The other options are probably better. -- EricHopper 2010-10-29 10:29
See also posting http://selenic.com/pipermail/mercurial/2008-July/020241.html: "Start of Mercurial git-fast-import importer (was p4 to hg)" by Paul Crowley
See also posting http://unixsadm.blogspot.com/2010/07/converting-perforce-depots-to-mercurial.html: "Converting Perfoce depots to Mercurial" by Criveti Mihai
Because of the threatening behavior of Larry McVoldemort of Bitmover, no Bitkeeper conversion tools have been made publicly available. See GenericConversion for details on building your own repository conversion tool.
Very experimental conversion script available if you can find nothing better:
12. Visual SourceSafe
14. Team Foundation Server (TFS)