= darcs backend for fast data importers Miklos Vajna == Purpose and Features darcs-fast-export is a tool to dump a http://darcs.net/[darcs] repository in a format understood by "fast-importers" such as http://git.or.cz/[git] http://www.kernel.org/pub/software/scm/git/docs/git-fast-import.html[fast-import]. It exhibits the following _features:_ Fast:: darcs-fast-export provides a fast darcs backend for fast-import. See link:t/bench-results/[here] for exact details. Correct:: darcs-fast-export produces correct results in any extreme cases. It has been tested with a collection of large darcs repos (called http://code.haskell.org/darcs/big-zoo/[big-zoo]). And several testcases under the `t/` directory. Independent:: Ideally it should work with any fast importer, but actually it has been tested with git fast-import, bzr fast-import and hg fastimport. (These are the three fast-import implementations available ATM.) Formats:: It supports the 'darcs-2', 'hashed', and 'old-fashioned-inventory' darcs repository formats. Incremental conversions:: It supports the usual `--export-marks` / `--import-marks` switches to allow incremental conversion. Wrapper scripts:: A wrapper script called `d2x` is available if you find typing `--export-marks` / `--import-marks` all the time boring. A similar one is also provided for the other direction, called `x2d`. Finally, if you want to work on darcs repos with git, you can use the `git-darcs` wrapper. Author mappings:: Supports `--authors-file` option like Git's SVN adaptor, for DARCS repositories that originated in CVS or SVN. Import script:: The pair of `darcs-fast-export`, `darcs-fast-import` is also included in this repo. It has been tested with the fast-expoters of Git, Hg, Bzr and - of course - Darcs itself. Two-way sync:: Using `darcs-fast-export` / `darcs-fast-import`, it is possible to convert a darcs repo to an other VCS, work there, then convert your work back to Darcs (or vica versa). This has been tested with "darcs -> git; hack hack; git -> darcs". == Usage See the manpages: * link:darcs-fast-export.html[darcs-fast-export] * link:darcs-fast-import.html[darcs-fast-import] * link:d2x.html[d2x] * link:x2d.html[x2d] * link:git-darcs.html[git-darcs] === Example Assuming that `test/` is a darcs repo, you could do this: ---- $ mkdir test.git $ cd test.git $ git --bare init $ cd .. $ darcs-fast-export test |(cd test.git; git fast-import) ---- For more examples (especially for bzr and hg), see the `t/` directory. == Download Using git: ---- $ git clone git://vmiklos.hu/darcs-fast-export ---- == Status In general, darcs-fast-export should work fine. darcs-fast-import has known problems with tags - other than that it should be okay. git-darcs should work properly as long as you are not paying too much attention to the imported tags (newly created tags won't be pushed back). darcs-fast-export has been tested with the following versions: Darcs version (see http://bugs.darcs.net/issue844[this bug] on why do you need such a new version): ---- $ darcs --version 2.2.0 (release) ---- Git version: ---- $ git --version git version 1.6.0.2 ---- Bzr versions: ---- $ bzr version Bazaar (bzr) 1.12 $ (cd ~/bzr/fastimport; bzr log --limit 1|grep revno) revno: 181 ---- Yes, you need the fastiport plugin from BZR, the last hg release series supported by fastimport-0.6 is hg-1.0.x. Mercurial (Hg) version: ---- $ hg version Mercurial Distributed SCM (version 1.3) ---- Strictly speaking this document is a wrong place to talk about configuring hg fastimport. However... you will need something like: ---- $ hg clone http://vc.gerg.ca/hg/pyfastimport $ hg clone http://vc.gerg.ca/hg/hg-fastimport $ sudo ln -s /path/to/pyfastimport/fastimport /usr/lib/python2.6/site-packages/fastimport $ sudo ln -s /path/to/hg-fastimport/hgfastimport /usr/lib/python2.6/site-packages/hgfastimport echo -e "[extensions]\nfastimport = /usr/lib/python2.6/site-packages/hgfastimport" > ~/.hgrc ---- and once you installed the plugin correctly, you should have something like: ---- $ ls /usr/lib/python*/site-packages/hgext/fastimport/__init__.py /usr/lib/python2.5/site-packages/hgext/fastimport/__init__.py ---- == Additional resources You can reach the Changelog link:Changelog[here], and a gitweb interface http://vmiklos.hu/gitweb/?p=darcs-fast-export.git[here]. The fast-import stream format documentation is http://git.kernel.org/?p=git/git.git;a=blob;f=fast-import.c;hb=HEAD[here] if you're interested. == Alternatives - http://repo.or.cz/w/darcs2git.git[darcs2git] tries to find conflict resolutions (to map them to merge commits), but it's rather slow because of this. It does not support the darcs2 format and/or incremental conversions, either. darcs-fast-export may support mapping to merge commits later, but not before http://bugs.darcs.net/issue1261[this issue] is addressed. - http://progetti.arstecnica.it/tailor[tailor] is an any2any VCS converter, but it produces corrupted results when converting the big-zoo - see http://progetti.arstecnica.it/tailor/ticket/171[this ticket]. - http://git.sanityinc.com/?p=darcs-to-git.git[darcs-to-git] is similar to darcs2git, but it fails for the testcases found in the testsuite of darcs-fast-export. - http://github.com/freshtonic/undarcs/tree/master[undarcs] claims to be fast, but its own README says it produces incorrect results. When I tried, it did not handle the darcs2 format, binary files and incremental support. == Thanks - Jason Dagit for helping me with darcs2 issues - Shawn O. Pearce and Johannes Schindelin for writing `git-fast-import` / `git-fast-export` - Ian Clatworthy for writing bzr fast-import - Paul Crowley for writing hg fast-import - Matthias Andree for assorted improvements, among them the --help, --encoding and --authors-file features (using Python's optparse), support for hashed repositories, `_darcs/format` interpretation, and mangling whitespace in tags to cope with repos imported into DARCS from CVS. - Pieter de Bie for writing git-bzr, which was the base of git-darcs