[PATCH 00/23] nd/sparse reroll

Compared to the current series in pu, patch "Teach Git to respect
skip-worktree (reading part)" has been broken up into smaller patches.
builtin-commit.c is also fixed to make the two failed test cases in
t7011 now pass. Skip-worktree bit no longer relies on
CE_MATCH_IGNORE_VALID flag, which means 
"git update-index --really-refresh" respects skip-worktree bit too.  

The rest is unchanged.

Nguyễn Thái Ngọc Duy (23):
  update-index: refactor mark_valid() in preparation for new options
  Add test-index-version
  Introduce "skip-worktree" bit in index, teach Git to get/set this bit
  update-index: ignore update request if it's skip-worktree
  Teach ls-files and update-index to respect skip-worktree bit
  Teach diff machinery to respect skip-worktree bit
  Teach grep to respect skip-worktree bit
  Teach commit to respect skip-worktree bit
  Teach Git to respect skip-worktree bit (writing part)
  Avoid writing to buffer in add_excludes_from_file_1()
  Read .gitignore from index if it is skip-worktree
  unpack-trees(): carry skip-worktree bit over in merged_entry()
  excluded_1(): support exclude files in index
  dir.c: export excluded_1() and add_excludes_from_file_1()
  Introduce "sparse checkout"
  unpack-trees(): add CE_WT_REMOVE to remove on worktree alone
  unpack-trees.c: generalize verify_* functions
  unpack-trees(): "enable" sparse checkout and load
    $GIT_DIR/info/sparse-checkout
  unpack_trees(): apply $GIT_DIR/info/sparse-checkout to the final
    index
  unpack-trees(): ignore worktree check outside checkout area
  read-tree: add --no-sparse-checkout to disable sparse checkout
    support
  Add tests for sparse checkout
  sparse checkout: inhibit empty worktree

 .gitignore                                        |    1 +
 Documentation/config.txt                          |    4 +
 Documentation/git-ls-files.txt                    |    1 +
 Documentation/git-read-tree.txt                   |   52 ++++++-
 Documentation/git-update-index.txt                |   29 ++++
 Documentation/technical/api-directory-listing.txt |    3 +
 Makefile                                          |    1 +
 builtin-apply.c                                   |    2 +-
 builtin-clean.c                                   |    4 +-
 builtin-commit.c                                  |   11 +-
 builtin-grep.c                                    |    2 +-
 builtin-ls-files.c                                |   11 +-
 builtin-read-tree.c                               |    4 +-
 builtin-update-index.c                            |   78 ++++++----
 cache.h                                           |   10 +-
 config.c                                          |    5 +
 diff-lib.c                                        |    5 +-
 diff.c                                            |    2 +-
 dir.c                                             |  100 ++++++++----
 dir.h                                             |    4 +
 entry.c                                           |    2 +-
 environment.c                                     |    1 +
 read-cache.c                                      |   17 ++-
 t/t1011-read-tree-sparse-checkout.sh              |  150 +++++++++++++++++
 t/t2104-update-index-skip-worktree.sh             |   57 +++++++
 t/t3001-ls-files-others-exclude.sh                |   22 +++
 t/t7011-skip-worktree-reading.sh                  |  158 ++++++++++++++++++
 t/t7012-skip-worktree-writing.sh                  |  139 ++++++++++++++++
 t/t7300-clean.sh                                  |   19 +++
 test-index-version.c                              |   14 ++
 unpack-trees.c                                    |  181 +++++++++++++++++++--
 unpack-trees.h                                    |    6 +
 32 files changed, 994 insertions(+), 101 deletions(-)
 create mode 100755 t/t1011-read-tree-sparse-checkout.sh
 create mode 100755 t/t2104-update-index-skip-worktree.sh
 create mode 100755 t/t7011-skip-worktree-reading.sh
 create mode 100755 t/t7012-skip-worktree-writing.sh
 create mode 100644 test-index-version.c