Re: [PATCH v2] diff-lib.c: adjust position of i-t-a entries in diff

[Junio C Hamano <gitster@pobox.com>]

Michael J Gruber <git@drmicha.warpmail.net> writes:

> Nguyễn Thái Ngọc Duy venit, vidit, dixit 16.03.2015 14:56:
>
>> The test "cache-tree invalidates i-t-a paths" is marked failure
>> because I don't think removing "--cached" from "git diff" is the right
>> fix. This test relies on "diff --cached" behavior but the behavior now
>> has changed. We may need to revisit this test at some point in future.
>
> I can't quite follow that reasoning. If the test describes expected
> behavior which the patch breaks, then we should not apply the patch. If
> the patch changes behavior in an expected way, then we should change the
> test to match.

The offending one came from eec3e7e4 (cache-tree: invalidate i-t-a
paths after generating trees, 2012-12-16), which was a fix to an
earlier bug where a cache-tree written out of an index with i-t-a
entries had incorrect information and still claimed it is fully
valid after write-tree rebuilt it.  The test probably should add
another path without i-t-a bit, run the same "diff --cached" with
updated expectation before write-tre, and run the "diff --cached"
again to make sure it produces a result that match the updated
expectation.