[PATCH v5 00/11] Untracked cache improvements

Here is a new version of a patch series to improve the untracked cache feature.

This v5 implements core.untrackedCache as a tristate config variable. When it's `true`, Git commands, especially `git status`, should always add the untracked cache and use it, and when `false`, Git commands should remove it. The default is `keep` in which case the untracked cache is neither removed nor added, and used if it is there.

Patch 1/11 is a small bugfix that has not changed.

Patch 2/11 to 4/11 add some small features that are missing. There are no changes compared to v4.

Patchs 5/11 to 7/11 are some refactoring to prepare for the following patchs. The interface of the new functions has changed as they are now passed a "struct index_state *istate" parameter on which they will operate instead of modifying "the_index".

Patch 8/11 deals with the "ident" field in "struct untracked_cache". Following Torsten and Junio's suggestions, the differences compared to v4 are the following:

	- we store only the kernel "sysname" and not the full kernel version,
	- we match the full "ident" string instead of just the beginning of the string,
	- a warning has been improved.

Patch 9/11 adds core.untrackedCache. Following Junio's suggestions, it has been changed compared to v4 in the following ways:

  - we don't die() and we exit 0, if "git update-index
  --[no-|force-]untracked-cache" is used in a way that goes against
  the value of core.untrackedCache,

  - we add or remove the untracked cache in read_index_from() instead
    of wt_status_collect_untracked().

Patch 10/11 is a new hack that is needed to have test-dump-untracked-cache work like it used to, now that we add or remove the untracked cache in read_index_from(). Because test-dump-untracked-cache indirectly calls read_index_from(), we have to prevent it from addind or removing the untracked cache.

Patch 11/11, which contains tests, has been changed to reflect changes in 9/11.

So the changes compared to v4 are mostly small updates, and patchs 8/11, 9/11 and 10/11.

The patch series is also available there:

https://github.com/chriscool/git/tree/uc-notifs63

Thanks to the reviewers and helpers.

Christian Couder (11):
  dir: free untracked cache when removing it
  update-index: use enum for untracked cache options
  update-index: add --test-untracked-cache
  update-index: add untracked cache notifications
  update-index: move 'uc' var declaration
  dir: add {new,add}_untracked_cache()
  dir: add remove_untracked_cache()
  dir: simplify untracked cache "ident" field
  config: add core.untrackedCache
  test-dump-untracked-cache: don't modify the untracked cache
  t7063: add tests for core.untrackedCache

 Documentation/config.txt               |  9 ++++
 Documentation/git-update-index.txt     | 67 +++++++++++++++++++++----
 builtin/update-index.c                 | 62 ++++++++++++++---------
 cache.h                                |  3 ++
 config.c                               | 23 +++++++++
 contrib/completion/git-completion.bash |  1 +
 dir.c                                  | 62 ++++++++++++++++++-----
 dir.h                                  |  3 +-
 environment.c                          |  6 +++
 read-cache.c                           | 14 ++++++
 t/t7063-status-untracked-cache.sh      | 89 +++++++++++++++++++++++++++++++---
 test-dump-untracked-cache.c            |  2 +
 12 files changed, 287 insertions(+), 54 deletions(-)