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

> Junio C Hamano <gitster@pobox.com> writes:
>
>> Ah, wait.
>>
>> I suspect that it all cancels out.
>> ...
>> Now, as you mentioned, there _may_ be codepaths that uses the same
>> definition of "what's in the index" as what diff-cache used to take
>> before your patches, and they may be broken by removing the
>> invalidation.  If we find such codepaths, we should treat their old
>> behaviour as buggy and fix them, instead of reintroducing the
>> invalidation and keep their current behaviour, as the new world
>> order is "i-t-a entries in the index does not yet exist."
>
> One potential negative consequence of the new world order I can
> immediately think of is this.  In many operations, we try to be
> lenient to changes in the working tree as long as the index is
> clean.  "read-tree -m" is the most visible one, where we require
> that the index and HEAD matches while allowing changes to working
> tree paths as long as they do not interfere with the paths that are
> involved in the merge.  We need to make sure that the path dir/bar
> added by "add -N dir/bar", which in the new world order does not
> count as "index is not clean and there is a difference from HEAD",
> (1) does not interfere with the mergy operation that wants to touch
> dir (which _could_ even be expected to be a file) or dir/bar, and
> (2) is not lost because the mergy operation wants to touch dir or
> dir/bar, for example.