Re: [PATCH 2/2] Add keyword unexpansion support to convert.c

On Tue, Apr 17, 2007 at 11:23:03AM -0700, Linus Torvalds wrote:

quoted

Well, if the only keyword we support is $BlobId:$, then if the tree/object
hasn't changed, then we still don't need to touch the object.

Not so?

Correct. However, is that actually a useful expansion?

Most of the time, I'd expect people to want things like "last committer, 
time, story of their life" etc.. I don't think the SHA1 ID's are pretty 
enough that anybody would ever want to see them. But yes, they are 
certainly stable.

I'd certainly settle for having only $Blobid:$. It fits my requirements
perfectly.

This is perhaps a reasonable wording of my requirement.
"Files from from the VCS should contain a stable machine-usable
identifier that is unique for that revision of the file, without
post-processing to insert the identifier."

In the case of CVS, $Header$ contains the path and revision number of a
file, which serve to identify the content uniquely.

In the case of Git, $BlobId$ fills the same requirement.

As for a usage case:
- J.PEBKAC.User gets a a tree (from a tarball or GIT, we should gain the
  same output)
- Copies some file outside of the tree (the user is NOT smart enough,
  and resists all reasonable attempts at edumacation)
- Modifies said file outside of tree.
- Contacts maintainer with entire changed file.
- User vanishes off the internet.

The entire file he sent if it's CVS, contains a $Header$ that uniquely
identifies the file (path and revision), and the maintainer can simply
drop the file in, and 'cvs diff -r$OLDREV $FILE'.
If it's git, the maintainer drops the file in, and does 'git diff
$OLDSHA1 $FILE'.

-- 
Robin Hugh Johnson
Gentoo Linux Developer & Council Member
E-Mail     : robbat2@gentoo.org
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