[Gnu-arch-users] Re: arch with 'special files'

[Josh England]

On Tue, 2005-03-29 at 11:01 +0200, Matthieu Moy wrote:
> Josh England <address@hidden> writes:
> 
> > I need to retain permissions on all files, 
> 
> Permission *and* ownership (arch doesn't store ownership. Most
> revision control systems won't because they're not designed to be used
> as root).

Of course.  However, I believe that full OS revision control is a
legitimate need that Arch could be ideally suited for.  

I'm pretty sure all the changes I'd like can be handled with more
(optional) metadata.  I'm not against some scripting glue, but to do
this I still need to be able to store/retrieve some metadata in the
archive.

How about this.  The 'file-metadata' and 'set-file-metadata' commands
could be modified to take a single user-defined metadata string (a
--userdef parameter?) which would be stored in the archive in some sane
way (similar to symlinks maybe).  'tla update' and such could quietly
ignore this string and not modify any files (or it could print a warning
saying that user-defined metadata has changed) -- since it is
user-defined, the user has to deal with it.  Changesets could simply
reflect that this metadata string has changed for a file.  With this, I
could add dummy files into the archive with enough metadata for a
wrapper script to be able to convert to/from a device/fifo/whatever.

Although an automatic --ownership flag would be nice, I can make do with
a single archived metadata string and use hooks/wrappers to take care of
the dirty work.

-JE

> > I'm not familiar with all the internals of arch, but all of this is
> > conceivable and should be fairly straight-forward since tar is the
> > file-store.
> 
> Actually, tar is just the way to serialize a changeset. The changeset
> mainly contains patches, not the files themselves. For example, arch
> manages symbolic links, but AFAIK, there are no symbolic links in arch
> changesets, but a description of the link in a "normal" file.
> 
> http://www.gnu.org/software/gnu-arch/tutorial/changeset-format.html
> 
> > Changesets of 'special' files would simply invoke 'mkfifo' or 'mknod' as
> > appropriate instead of 'patch' (or whatever).  This is, of course, very
> > UNIX-centric, but all the code could be #ifdef'd out for other
> > platforms.
> 
> That's a personal opinion (I'm not a tla developer) but I don't think
> you can hope an inclution of this in tla's mainline.
>