[PATCH v3 0/4] cache-tree building fix in the presence of ita entries

v3 fixes 2/2 (which is 4/4 now), allowing cache-tree to generate an empty tree if the index contains nothing but i-t-a entries.

Since empty tree SHA-1 is involved and we don't want to make it harder to move away from SHA-1 in future, 1/2 and 2/2 are added to keep SHA-1 for empty tree (and blob while we're at it) in one place.

Note that I didn't make lib-pack.sh and t5308 use $_EMPTY_BLOB because the actual SHA-1 characters matter (t5308) and I'm not so sure about variable expansion in the case/esac block and not wanting to check all the shells out there again (lib-pack.sh).

Nguyễn Thái Ngọc Duy (4):
  test-lib.sh: introduce and use $_EMPTY_TREE
  test-lib.sh: introduce and use $_EMPTY_BLOB
  cache-tree.c: fix i-t-a entry skipping directory updates sometimes
  cache-tree: do not generate empty trees as a result of all i-t-a subentries

 cache-tree.c                         | 11 +++++++++--
 t/t0000-basic.sh                     |  2 +-
 t/t1011-read-tree-sparse-checkout.sh |  8 ++++----
 t/t1100-commit-tree-options.sh       |  2 +-
 t/t1700-split-index.sh               | 24 ++++++++++++------------
 t/t2203-add-intent.sh                | 31 +++++++++++++++++++++++++++++++
 t/t3102-ls-tree-wildcards.sh         |  8 ++++----
 t/t4010-diff-pathspec.sh             |  6 ++----
 t/t4054-diff-bogus-tree.sh           | 10 ++++------
 t/t5504-fetch-receive-strict.sh      |  4 ++--
 t/t7011-skip-worktree-reading.sh     | 12 +++++-------
 t/t7012-skip-worktree-writing.sh     | 10 ++++------
 t/t7063-status-untracked-cache.sh    |  6 +++---
 t/t7508-status.sh                    |  2 +-
 t/test-lib.sh                        |  5 ++++-
 15 files changed, 87 insertions(+), 54 deletions(-)