[PATCH v3 0/9] read_tree() and read_tree_recursive() refactoring

A v3 of a refactoring of tree.c. See v2 at https://lore.kernel.org/git/20210308022138.28166-1-avarab@gmail.com/

This brings back pretty much the old read_tree_recursive() under the name read_tree_at() as suggested in https://lore.kernel.org/git/xmqqft106sok.fsf@gitster.g/

Ævar Arnfjörð Bjarmason (9):
  ls-files tests: add meaningful --with-tree tests
  tree.c API: move read_tree() into builtin/ls-files.c
  ls-files: don't needlessly pass around stage variable
  ls-files: refactor away read_tree()
  tree.h API: remove support for starting at prefix != ""
  tree.h API: remove "stage" parameter from read_tree_recursive()
  tree.h API: rename read_tree_recursive() to read_tree()
  show tests: add test for "git show <tree>"
  tree.h API: expose read_tree_1() as read_tree_at()

 archive.c                     |  19 +++---
 builtin/checkout.c            |   8 +--
 builtin/log.c                 |   8 +--
 builtin/ls-files.c            |  76 +++++++++++++++++++++-
 builtin/ls-tree.c             |   6 +-
 cache.h                       |   2 +-
 merge-recursive.c             |   6 +-
 t/t3060-ls-files-with-tree.sh |  41 ++++++++++++
 t/t7007-show.sh               |  39 ++++++++++++
 tree.c                        | 117 ++++------------------------------
 tree.h                        |  24 +++----
 11 files changed, 205 insertions(+), 141 deletions(-)

Range-diff:
 1:  6416da0dee2 =  1:  b338f2c01a4 ls-files tests: add meaningful --with-tree tests
 2:  765001b44cd !  2:  4578b83944c tree.c API: move read_tree() into builtin/ls-files.c
    @@ builtin/ls-files.c: static int get_common_prefix_len(const char *common_prefix)
       * Read the tree specified with --with-tree option
       * (typically, HEAD) into stage #1 and then
     
    + ## cache.h ##
    +@@ cache.h: static inline int index_pos_to_insert_pos(uintmax_t pos)
    + #define ADD_CACHE_OK_TO_ADD 1		/* Ok to add */
    + #define ADD_CACHE_OK_TO_REPLACE 2	/* Ok to replace file/directory */
    + #define ADD_CACHE_SKIP_DFCHECK 4	/* Ok to skip DF conflict checks */
    +-#define ADD_CACHE_JUST_APPEND 8		/* Append only; tree.c::read_tree() */
    ++#define ADD_CACHE_JUST_APPEND 8		/* Append only */
    + #define ADD_CACHE_NEW_ONLY 16		/* Do not replace existing ones */
    + #define ADD_CACHE_KEEP_CACHE_TREE 32	/* Do not invalidate cache-tree */
    + #define ADD_CACHE_RENORMALIZE 64        /* Pass along HASH_RENORMALIZE */
    +
      ## tree.c ##
     @@
      
 3:  a71ffba7d04 =  3:  33656ff63b8 ls-files: don't needlessly pass around stage variable
 4:  e78d1810b89 =  4:  1c96d5d3611 ls-files: refactor away read_tree()
 5:  05eecdd7519 !  5:  367cb99224b tree.h API: remove support for starting at prefix != ""
    @@ Commit message
         ffd31f661d5 (Reimplement read_tree_recursive() using
         tree_entry_interesting(), 2011-03-25).
     
    -    If in the future we need to support recursively reading trees without
    -    starting at the root we can easily add a read_tree_recursive_subdir(),
    -    and make that function a thin wrapper for read_tree_1().
    +    As it turns out (Murphy's law and all) we're just about to gain a new
    +    in-tree user that would need this parameter[1]. Let's remove it anyway
    +    as the common case is going to be to not supply it, A later commit
    +    will bring back this functionality in different form.
     
    -    In the meantime there's no reason to keep around what amounts to dead
    -    code, just in case we need it in the future.
    +    1. https://lore.kernel.org/git/xmqqft106sok.fsf@gitster.g/
     
         Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
     
 6:  fcecc82e1c8 =  6:  38e36780e22 tree.h API: remove "stage" parameter from read_tree_recursive()
 -:  ----------- >  7:  859902ffd83 tree.h API: rename read_tree_recursive() to read_tree()
 -:  ----------- >  8:  a63c9b49f13 show tests: add test for "git show <tree>"
 -:  ----------- >  9:  570642c8625 tree.h API: expose read_tree_1() as read_tree_at()