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Re: cvs2svn conversion directly to git ready for experimentation

From
Michael Haggerty <mhagger@alum.mit.edu>
Date
Aug 3, 2007, 08:36 UTC
Message-ID
<46B2E8F3.30301@alum.mit.edu>
In-Reply-To
<46a038f90708021608o21480074ybcfada767afc7b04@mail.gmail.com>
Martin Langhoff wrote:
> Is there any way we can run tweak cvs2svn to run incrementals, even if
> not as fast as cvsps/git-cvsimport? The "do it remotely" part can be
> worked around in most cases.

I don't see any fundamental reason why not, but I think it would be a significant amount of work. There are two main issues:

1. With CVS, it is possible to change things retroactively, such as
changing which version of a file is included in a tag, or adding a new
file to a tag, or changing whether a file is text vs. binary.  And many
people copy and/or rename files within the CVS repository itself (to get
around CVS's inability to rename a file).  This makes it look like the
file has *always* existed under the new name and *never* existed under
the old name.  An incremental conversion tool would have to look
carefully for such changes and either handle them properly or complain
loudly and abort.
2. cvs2svn uses a lot of repository-wide information to make decisions
about how to group CVSItems into changesets, and a lot of these
decisions are based on heuristics.  Incremental conversion would require
that the decisions made in one cvs2svn run are recorded and treated as
unalterable in subsequent runs.

This hasn't been a priority in the Subversion world, because, frankly, what reason would a person have to stick with CVS instead of switching to Subversion, given that (1) they are intentionally so similar in workflow, an (2) there is no significant competition from other centralized SCMs? But of course until the distributed SCM playing field has been thinned out a bit, people will probably be reluctant to commit to one or the other.

I don't expect to have time to implement incremental conversions in cvs2svn in the near future. (I'd much rather work on output back ends to other distributed SCMs.) But if any volunteers step forward (hint, hint) I would be happy to help them get started and answer their questions. I think that cvs2svn is quite hackable now, so the learning curve is hopefully much less frightening than when I started on the project :-)

Michael
Previous: Steffen ProhaskaNext: Patwardhan, Rajesh
Message 33 of 40 in “cvs2svn conversion directly to git ready for experimentation”
  1. Michael HaggertyAug 1, 2007
  2. Johannes SchindelinAug 1, 2007
  3. Jakub NarebskiAug 1, 2007
  4. Michael HaggertyAug 2, 2007
  5. Jon SmirlAug 2, 2007
  6. Steffen ProhaskaAug 2, 2007
  7. Michael HaggertyAug 2, 2007
  8. Marko MacekAug 2, 2007
  9. Jon SmirlAug 2, 2007
  10. Oswald BuddenhagenAug 5, 2007
  11. Simon 'corecode' SchubertAug 2, 2007
  12. Steffen ProhaskaAug 2, 2007
  13. Simon 'corecode' SchubertAug 2, 2007
  14. Robin RosenbergAug 2, 2007
  15. Lübbe OnkenAug 2, 2007
  16. Lübbe OnkenAug 2, 2007
  17. Steffen ProhaskaAug 2, 2007
  18. Simon 'corecode' SchubertAug 2, 2007
  19. Michael HaggertyAug 2, 2007
  20. Simon 'corecode' SchubertAug 3, 2007
  21. Steffen ProhaskaAug 4, 2007
  22. Shawn O. PearceAug 3, 2007
  23. Michael HaggertyAug 2, 2007
  24. Linus TorvaldsAug 2, 2007
  25. Michael HaggertyAug 2, 2007
  26. Shawn O. PearceAug 3, 2007
  27. Jon SmirlAug 2, 2007
  28. Michael HaggertyAug 2, 2007
  29. Martin LanghoffAug 2, 2007
  30. Johannes SchindelinAug 3, 2007
  31. Steffen ProhaskaAug 3, 2007
  32. Steffen ProhaskaAug 3, 2007
  33. Michael HaggertyAug 3, 2007
  34. Patwardhan, RajeshAug 3, 2007
  35. Jon SmirlAug 3, 2007
  36. Patwardhan, RajeshAug 3, 2007
  37. Michael HaggertyAug 3, 2007
  38. Jon SmirlAug 3, 2007
  39. Jon SmirlAug 3, 2007
  40. Lübbe OnkenAug 2, 2007

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