[Gnu-arch-users] Re: Re: give us a hand with arch

[Pau Aliagas]

On Sun, 28 Sep 2003, Andrea Arcangeli wrote:

Andrea, you still have a few things to learn :)
I see that explicit is right for you, but so is tagline, as I'll show you 
now.

> No need to be disappointed, the tagline is the best you can do w/o
> kernel support to make it trasparent as it should have been (assuming
> you don't want to call move-tag and friends).

The files metadata has been discussed to death here. There are pros and 
cons. The main con is that you limit the filesystems you can use. I.e Tom 
uses BSD, not Linux. There's people using it via cygwin....

> It's just that I prefer having to call move-tag/add-tag/delete-tag

That's fine, but some of us don't. tagline let's you use both at the same 
time. Choosing it now is better for you as there is no easy way of 
migrating one project from one naming mehod to the other by now.
You can act as if explicit was the method, just pretend it's so.

> then to pollute the data with metadata in non standard formats and that
> doesn't provide math safety across the tree since anybody can add
> "arch-tag: foo" simultaneously in all files.

That's not possible. Arch won't let you commit two identical tags, be it
expicit or tagline. You can use tla tree-lint to check the tree integrity.
So the first committed tag will have preference and the second will be 
treated as a clash. As tags should be unique, the common practice has 
become to use a uud, easyly generated in linux (cat 
/proc/sys/kernel/random/uuid). The tag is only important to track a file's 
history, so it's better not to try to use descriptive names that, I can 
say by experience, change over time.

> The day we'll have multiple channels in the inode, or a way to bind two
> files together, we won't need to call move-tag and friends anymore, and
> still it will be the explicit mode, never the tagline.

When this happens (I want to see the working code), maybe it will be
easier to edit file forks (or xattrs); meanwhile adding a tagline is far
mor convenient. Or tla add/move etc in your case.

Pau