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Re: Cross-Platform Version Control

From
Linus Torvalds <torvalds@linux-foundation.org>
Date
May 13, 2009, 21:10 UTC
Message-ID
<alpine.LFD.2.01.0905131401170.3343@localhost.localdomain>
In-Reply-To
<op.utvy5mie1e62zd@merlin.emma.line.org>
On Wed, 13 May 2009, Matthias Andree wrote:
Show 14 quoted lines
> Am 13.05.2009, 19:12 Uhr, schrieb Linus Torvalds
> <torvalds@linux-foundation.org>:
> 
> > Use <stringprep.h> and stringprep_utf8_nfkc_normalize() or something to do
> > the actual normalization if you find characters with the high bit set. And
> > since I know that the OS X filesystems are so buggy as to not even do that
> > whole NFD thing right, there is probably some OS-X specific "use this for
> > filesystem names" conversion function.
> 
> Sorry for interrupting, but NF_K_C? You don't want that (K for compatibility,
> rather than canonical, normalization) for anything except normalizing
> temporary variables inside strcasecmp(3) or similar. Probably not even that.
> The normalizations done are often irreversible and also surprising. You don't
> want to turn 2³.c into 23.c, do you?

No, you're right. We want just plain NFC. I just googled for how some other projects handled this, and found the stringprep thing in a post about rsync, and didn't look any closer.

But yes, you're absolutely right, stringprep is total crap, and nfkc is horrible.

I have no idea of what library to use, though. For perl, there's Unicode::Normalize, but that's likely still subtly incorrect for the OS-X case due to the filesystem not using _strict_ NFD.

I have this dim memory of somebody actually pointing to the documentation of exactly which characters OS X ends up decomposing. Maybe we could just do a git-specific inverse of that, knowing that NOBODY ELSE IN THE WHOLE UNIVERSE IS SO TERMINALLY STUPID AS TO DO THAT DECOMPOSITION, and thus the OS X case is the only one we need to care about?

			Linus
Previous: Matthias AndreeNext: Jay Soffian
Message 24 of 59 in “Re: Cross-Platform Version Control”
  1. Esko LuontolaMay 12, 2009
  2. Shawn O. PearceMay 12, 2009
  3. Johannes SchindelinMay 12, 2009
  4. Esko LuontolaMay 12, 2009
  5. Johannes SchindelinMay 12, 2009
  6. Esko LuontolaMay 12, 2009
  7. Johannes SchindelinMay 13, 2009
  8. Esko LuontolaMay 13, 2009
  9. Alex RiesenMay 13, 2009
  10. Johannes SchindelinMay 13, 2009
  11. Jeff KingMay 12, 2009
  12. Johannes SchindelinMay 12, 2009
  13. Linus TorvaldsMay 13, 2009
  14. Linus TorvaldsMay 13, 2009
  15. Andreas EricssonMay 13, 2009
  16. Linus TorvaldsMay 13, 2009
  17. Martin LanghoffMay 13, 2009
  18. Linus TorvaldsMay 13, 2009
  19. Theodore TsoMay 13, 2009
  20. Linus TorvaldsMay 13, 2009
  21. Daniel BarkalowMay 13, 2009
  22. Linus TorvaldsMay 13, 2009
  23. Matthias AndreeMay 13, 2009
  24. Linus TorvaldsMay 13, 2009
  25. Jay SoffianMay 13, 2009
  26. Matthias AndreeMay 13, 2009
  27. Dmitry PotapovMay 12, 2009
  28. Martin LanghoffMay 12, 2009
  29. Jakub NarebskiMay 12, 2009
  30. Extend sample pre-commit hook to check for non ascii file/usernamesHeiko Voigt, May 12, 2009
  31. Jakub NarebskiMay 12, 2009
  32. Extend sample pre-commit hook to check for non ascii filenamesHeiko Voigt, May 14, 2009
  33. Martin LanghoffMay 15, 2009
  34. Heiko VoigtMay 18, 2009
  35. Jakub NarebskiMay 18, 2009
  36. check for filenames that only differ in case to sample pre-commit hookHeiko Voigt, Jun 20, 2009
  37. Jakub NarebskiMay 15, 2009
  38. Extend sample pre-commit hook to check for non ascii filenamesHeiko Voigt, May 18, 2009
  39. Johannes SixtMay 18, 2009
  40. Heiko VoigtMay 18, 2009
  41. Johannes SixtMay 18, 2009
  42. Extend sample pre-commit hook to check for non ascii filenamesHeiko Voigt, May 19, 2009
  43. Junio C HamanoMay 18, 2009
  44. Julian PhillipsMay 18, 2009
  45. Junio C HamanoMay 15, 2009
  46. Peter KreftingMay 14, 2009
  47. Esko LuontolaMay 14, 2009
  48. Andreas EricssonMay 14, 2009
  49. Johannes SchindelinMay 14, 2009
  50. Dmitry PotapovMay 15, 2009
  51. Cross-Platform Version ControlJohn Tapsell, May 13, 2009
  52. Jay SoffianMay 13, 2009
  53. Alex RiesenMay 13, 2009
  54. Jay SoffianMay 13, 2009
  55. John TapsellMay 13, 2009
  56. Nicolas PitreMay 13, 2009
  57. Johannes SchindelinMay 13, 2009
  58. Andreas EricssonMay 13, 2009
  59. Miles BaderMay 14, 2009

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