Make :(attr) pathspec work with "git log"

When :(attr) was added, it supported one of the two main pathspec matching functions, the one that works on a list of paths. The other one works on a tree, tree_entry_interesting(), which gets :(attr) support in this series.

With this, "git grep <pattern> <tree> -- :(attr)" or "git log :(attr)" will not abort with BUG() anymore.

But this also reveals an interesting thing: even though we walk on a tree, we check attributes from _worktree_ (and optionally fall back to the index). This is how attributes are implemented since forever. I think this is not a big deal if we communicate clearly with the user. But otherwise, this series can be scraped, as reading attributes from a specific tree could be a lot of work.

The main patch is the last one. The others are just to open a path to pass "struct index_state *" down to tree_entry_interesting(). This may become standard procedure because we don't want to stick the_index (or the_repository) here and there.

Nguyễn Thái Ngọc Duy (5):
tree.c: make read_tree*() take 'struct repository *' tree-walk.c: make tree_entry_interesting() take an index pathspec.h: clean up "extern" in function declarations dir.c: move, rename and export match_attrs()
tree-walk: support :(attr) matching

 Documentation/glossary-content.txt |  2 +
 archive.c                          |  6 +-
 builtin/checkout.c                 |  3 +-
 builtin/grep.c                     |  3 +-
 builtin/log.c                      |  5 +-
 builtin/ls-files.c                 |  2 +-
 builtin/ls-tree.c                  |  3 +-
 builtin/merge-tree.c               |  2 +-
 dir.c                              | 41 +-------------
 list-objects.c                     |  3 +-
 merge-recursive.c                  |  3 +-
 pathspec.c                         | 38 +++++++++++++
 pathspec.h                         | 27 +++++----
 revision.c                         |  1 +
 t/t6135-pathspec-with-attrs.sh     | 58 ++++++++++++++++++-
 tree-diff.c                        |  3 +-
 tree-walk.c                        | 89 ++++++++++++++++++++++--------
 tree-walk.h                        | 10 ++--
 tree.c                             | 21 ++++---
 tree.h                             | 18 +++---
 unpack-trees.c                     |  6 +-
 21 files changed, 235 insertions(+), 109 deletions(-)

2.19.1.1327.g328c130451.dirty