On Tue, Apr 09, 2013 at 01:57:21PM -0700, Junio C Hamano wrote:
> John Keeping <j...@keeping.me.uk> writes:
>
> > This adds a prefix string to any filename arguments encountered after it
> > has been specified.
> >
> > Signed-off-by: John Keeping <j...@keeping.me.uk>
> > ---
>
> Stale subject?
Yep. Sorry.
> > +--prefix <arg>::
> > + Behave as if 'git rev-parse' was invoked from the `<arg>`
> > + subdirectory of the working tree. Any relative filenames are
> > + resolved as if they are prefixed by `<arg>` and will be printed
> > + in that form.
> > ++
> > +This can be used to convert arguments to a command run in a subdirectory
> > +so that they can still be used after moving to the top-level of the
> > +repository. For example:
> > ++
> > +----
> > +prefix=$(git rev-parse --show-prefix)
> > +cd "$(git rev-parse --show-toplevel)"
> > +eval "set -- $(git rev-parse --sq --prefix "$prefix" "$@")"
>
> I think you should tighten rev-parse parameter to reject options and
> revisions, especially as an example to teach how to use it. When
> the user said
>
> git mylog -U20 master..next -- README
>
> inside Documentation/ directory, "git-mylog" script would want to
> see README prefixed with Documentation/ but want to see -U20 or
> master..next untouched.
And it will if it runs:
git rev-parse --prefix Documentation/ -U20 master..next -- README
Which gives:
-U20
f131fb6eb2a1e09f7ce53d148e21ce6960f42422
^fa7285dc3dce8bd01fd8c665b032603ed55348e5
--
Documentation/README
> Historically, rev-parse was a way to sift
> options and args meant for rev-list from those mant for diff-tree
> so that a variant of
>
> git rev-list $(git rev-parse --revs) "$@" |
> git diff-tree --stdin $(git rev-parse --no-revs)
>
> can be used to implement such "git mylog" script.
>
> I think "--no-revs --no-flags" is how you ask it to give you only
> the paths, but I am writing from memory so please double check.
>
> Having said all that.
>
> Existing scripts (e.g. "git am") do this kind of things without such
> an option added to rev-parse. They first do:
>
> prefix=$(git rev-parse --show-prefix)
>
> and refer to "$prefix/$1", "$prefix/$2", etc., I think.
>
> Is this option really necessary to update "git submodule"? Don't we
> have a much better idea which parameter holds user-supplied path in the
> script than having rev-parse make a guess on the entire "$@"?
It's not guessing on all of "$@" in git-submodule - we know that
everything left is a path.
I've looked at git-am and hadn't thought of doing that, just thought
this was a reasonably elegant way of processing the arguments. I'm
happy to try another approach if that's going to be more acceptable.
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