Re: [PATCH 2/2] diff_index: honor in-index, not working-tree, .gitattributes

From: Jay Soffian <jaysoffian@gmail.com>
Date: Sep 23, 2011, 00:38 UTC
Message-ID: <CAG+J_DzUQ3OGfiX=vHVGC7SHvwToVjD7uwFyDa8Tq6t7YwX12Q@mail.gmail.com>
In-Reply-To: <7v8vpgxkvb.fsf@alter.siamese.dyndns.org>

On Thu, Sep 22, 2011 at 6:39 PM, Junio C Hamano <gitster@pobox.com> wrote:

Show 18 quoted lines

> Jay Soffian <jaysoffian@gmail.com> writes:
>
>> When diff'ing the index against a tree (using either diff-index
>> or diff --cached), git previously looked at .gitattributes in the
>> working tree before considering .gitattributes in the index, even
>> though the diff itself otherwise ignores the working tree.
>
> We can take attributes only from one place (so far from the working tree
> and perhaps from the index), people had to live within the limitation that
> comes from the "single source only" semantics. It also happens to be
> easier to understand (recall the complexity of the examples Jeff gave
> about "textconv" during "diff" which ideally should apply from its own
> side and "funcname", which does not even have a right answer).
>
> In practice, because development progresses by making everything
> (including the .gitattributes file) better, I think "use the newer one"
> would be a good compromise when we have two possible sources to grab
> attributes from but we can only use one source.

I agree with that...

> In that sense, I am somewhat skeptical about what this patch tries to
> do. The working tree is where people make the progress to update the
> index.

... but it still seems inconsistent that --cached ignores the working tree except for .gitattributes.

This also happens to be the only way to get diff-index to work with a bare repo and temporary (on-disk) index. But that's less important if we implement what's suggested in the next paragraph.

Show 10 quoted lines

> A related tangent.
>
> I think the logical conclusion of assuming that we will keep the "single
> source only" semantics (which I think we will, by the way, unless I hear a
> concrete proposal to how we apply attributes from more than one sources in
> what way to which side of the diff) is that a patch might be an
> improvement over the current behaviour if it teaches "diff-tree" to read
> from the tree and populate the in-core index (never writing it out to
> $GIT_DIR/index) from the postimage tree (i.e. "diff preimage postimage" or
> "diff -R postimage preimage") when it is run in a bare repository.

Okay, I can give that a try.

> It
> would be a regression if the attributes mechanism is used for auditing
> purposes (as we start reading from a tree that is being audited using the
> very attributes it brings in), though.

--[no-]tree-attributes?

j.