[PATCH v3 0/6] stash: drop usage of a second index

[Alban Gruin <alban.gruin@gmail.com>]

The old scripted `git stash' used to create a second index to save
modified and untracked files, and restore untracked files, without
affecting the main index.  This behaviour was carried on when it was
rewritten in C, and here, most operations performed on the second index
are done by forked commands (ie. `read-tree' instead of reset_tree(),
etc.).

The goal of this series is to modernise (a bit) builtin/stash.c.

Originally, this series was also meant to fix a bug reported by Son
Luong Ngoc [0], but as emphasized by Gábor [1], the issue is not limited
to `git stash', so this series is not a good fix for this particular
issue.

This series is based on a08a83db2b (The sixth batch, 2020-06-29), and it
applies cleanly on top of the current master (e8ab941b67 (The second
batch -- mostly minor typofixes, 2020-07-30)).

The tip of this series is tagged as "stash-remove-second-index-v3" at
https://github.com/agrn/git.

[0] https://lore.kernel.org/git/EED2CFF1-5BEF-429D-AB99-AD148A867614@gmail.com/
[1] https://lore.kernel.org/git/20200615152715.GD2898@szeder.dev/

Changes since v2:

 - Typofix in the fifth patch, noticed by Christian Couder.

Alban Gruin (6):
  stash: mark `i_tree' in reset_tree() const
  stash: remove the second index in stash_working_tree()
  stash: remove the second index in stash_patch()
  stash: remove the second index in save_untracked_files()
  stash: remove the second index in restore_untracked()
  stash: remove `stash_index_path'

 builtin/stash.c | 156 +++++++++++++++---------------------------------
 1 file changed, 48 insertions(+), 108 deletions(-)

Range-diff against v2:
1:  598f03e76e = 1:  598f03e76e stash: mark `i_tree' in reset_tree() const
2:  7265cfe65c = 2:  7265cfe65c stash: remove the second index in stash_working_tree()
3:  b5587c0d56 = 3:  b5587c0d56 stash: remove the second index in stash_patch()
4:  5fbcddf899 = 4:  5fbcddf899 stash: remove the second index in save_untracked_files()
5:  0338986339 ! 5:  a12a923014 stash: remove the second index in restore_untracked()
    @@ -6,7 +6,7 @@
     
         The call to `read-tree' is replaced by reset_tree() with the appropriate
         parameters (no update, no reset).  The environment of `checkout-index'
    -    is no longer modified, and the cache is discarded when it exists.
    +    is no longer modified, and the cache is discarded when it exits.
     
         In do_apply_stash(), the changes are a bit more involved: to avoid
         conflicts with the merged index, restore_untracked() is moved after
6:  4f151f4600 = 6:  dd25e71f35 stash: remove `stash_index_path'
-- 
2.20.1