Subject: Re: `git check-attr' problems & questions

From: Jonathan Nieder <[email-masked]>
Date: Sat, 27 Mar 2010 20:42:08 -0500

Hi,

[quoted text reordered for convenience]

Eli Barzilay wrote:

> I'm trying to use .gitattributes to use some custom properties that we
> have in an svn repository which is migrating to git,
[...]
> So my first question is -- am I missing something obvious?  It almost
> looks like `check-attr' is intended only for low-level use...

Yep.  It’s listed under “purehelpers” (Internal helper commands) in
command-list.txt and hence git(1).  I suspect a good place to put
a user-visible equivalent would be a future ‘git ls’ command [1].

Therefore...

> Fixing the first problem seems like it would be easy with a quick
> shell script (maybe even with just an alias),

If it proves pleasant to use, it would be very nice if you could send
a copy of such a shell script after a while.  Experiments like this
are the foundation of a good UI.

> 2. I'm also trying to use an attribute on a hook script on the server
>    (with the idea that email notifications are sent according to the
>    set of modified files) -- but it looks like `git check-attr'
>    doesn't work on a bare repository.

Current ‘git check-attr’ reads its attributes from actual .gitattribute
files in the work tree first and then examines the versions registered
in the index.  So the secret is to read the .gitattribute files you care
about into a temporary index file --- e.g., something like this.

 : "Usage: $0 commit check-attr-args" &&

 GIT_INDEX=tmp-index git read-tree --reset -i "$1" &&
 shift &&
 GIT_INDEX=tmp-index git check-attr "$@" &&
 rm tmp-index

Ideally, check-attr should learn an option to set a different policy
(e.g., index-only) with git_attr_set_direction(), but that is a
different story.

>    instead of showing an error, it actually succeeds after
>    showing that the attribute is "unspecified".

Probably it should learn to error out when it expects to use a work
tree but there is none.  git_attr_set_direction() does this.

> And the last question -- is there anything that does something like
> this customized email notifications that I'm trying to do?  (That is:
> an attribute that determines recipients, then a `post-receive' hook
> that builds a list of modified files, grabs all the corresponding
> values of this attributes, and that's makes up the recipient list to
> notify.)

Not that I know of.

HTH,
Jonathan

[1] I read the name from here:
http://thread.gmane.org/gmane.comp.version-control.git/136360
That series went in a different direction, though.
http://thread.gmane.org/gmane.comp.version-control.git/141678