[PATCH 0/3] i-t-a entries in git-status, and git-commit

Let's see if I can get the first commit graduated before it turns two years old. Six months to go! This series is about some oddities of intent-to-add entries (aka "git add -N"):

1) An ita entry in git-status shows that it's added in the index
   (compared to worktree) as a file change, not new file addition. And
   it shows the entry added to HEAD as an empty version. This is due
   to an implementation detail that i-t-a entries are registered in
   the index as empty blobs with a special flag.

2) When you do a "git commit" with no changes whatsoever, but you
   happen to have some ita entries registered, git-commit does not
   recognize the resulting commit would be empty and should be caught,
   unless --allow-empty is given. This has been reported several times.

3) Same symptom as 2) but with initial commit (diff code is not used
   for detecting empty commits this time). If you only have ita
   entries in the index by the time you make an initial commit, you'll
   create an empty commit even if --allow-empty is not specified.

1) and 2) are fixed by changing the position of ita entries in diff
code. ita entries should be seen as a new file when compared between
worktree and HEAD, and no change when compared between index and HEAD.

Some previous commit made this move globally and was reverted because it could have dangerous unseen side effects, especially in merge code. Now we are moving slowly towards that (first patch), this time we try to handle case by case (e.g. index_differs_from in the second patch).

3) could be handled pretty easily once you know the problem. This is
the third patch.

Nguyễn Thái Ngọc Duy (3):
  Resurrect "diff-lib.c: adjust position of i-t-a entries in diff"
  diff-lib.c: enable --shift-ita in index_differs_from()
  commit: don't be fooled by ita entries when creating initial commit

 Documentation/diff-options.txt |  7 +++++++
 builtin/commit.c               | 11 ++++++++---
 cache.h                        |  1 +
 diff-lib.c                     | 13 +++++++++++++
 diff.c                         |  2 ++
 diff.h                         |  1 +
 read-cache.c                   | 10 ++++++++++
 sequencer.c                    |  5 +++--
 t/t2203-add-intent.sh          | 41 +++++++++++++++++++++++++++++++++++++++--
 t/t7064-wtstatus-pv2.sh        |  4 ++--
 wt-status.c                    |  7 ++++++-
 11 files changed, 92 insertions(+), 10 deletions(-)