Re: [RFC] File system difference handling in git

[Junio C Hamano <gitster@pobox.com>]

"Reece Dunn" <msclrhd@googlemail.com> writes:

>   1.  File name representation
>
> For Linux file systems ...
> Therefore, you have:
>
>    os_to_git_path( const NATIVECHAR * ospath, strbuf * gitpath );
>    git_to_os_path( const char * gitpath, const NATIVECHAR * ospath, int oslen );

It is not that simple, I am afraid.  Legacy encodings can be
used in pathnames.  With bog-standard traditional UNIX pathname
semantics, all pathnames are sequences of non-NUL, non-slash
bytes, separated with slashes, so if you do not allow choices
(which is a very sensible ideal world scenario), you can declare
that the "git" encoding is UTF-8 and always check things out
as-is.

But if you want a project ("git" in your above parlance) to be
checked out in two repositories, one with legacy and the other
with UTF-8, you cannot just say os_to_git/git_to_os.  You would
need a bit more information from the repository owners what
encodings are suitable.  So your os_to_git()/git_to_os() will
not be an identity function even on Linux to support such.

I used to have a data directory on my Linux box with EUC-JP
pathname and exported as an SMB share to my wife's Windows box,
telling samba to transliterate to whatever encoding the other
end liked.  I did not want to have the pathname on the Linux end
in UTF-8 because I did not have enough energey to update my
Emacs configuration to grok Japanese in UTF-8 (even though I
finally bit the bullet and switched to UTF-8 on the Linux side
recently).

I know, this is painful.  Real life hurts.  Even on Linux,
not everybody can live in UTF-8-only world.

>   2.  Case (in)sensitivity
>
> Here, you have the following cases:
> ...
>   3.  git says that the files are different, but the filesystem says
> that the files are the same.
>
> Allow the move, updating the git directory tree only.

Sorry, I cannot really tell what you are talking about.  You
seem to imply, with "Allow the move", that you are describing a
scenario that involves a move of one existing file to another,
but it is not clear.  E.g. did you mean, by 3, "When the user
says 'move a b', and if git says a and b are different but if
the filesystem says a and b are the same, then..."?