[PATCH v3 0/6] Nominating "whatchanged" for removal

"git whatchanged" has outlived its usefulness when "git log" with various diff-related options more than 10 years ago. It is not even shorter to type than its rough equivalent "git log --raw". It is high time to start seeing if it is still being used, declare its official deprecation, and announce its removal in the future.

This iteration is more complete than the previous two iterations:

 * The first step is to refactor the mechanism to show the message
   to ask users to contact git@vger that they still use the command,
   out of "git pack-redundant" implementation.  This message is
   shown when the "--i-still-use-this" option is not passed to a
   command that requires it.

 * The second and the third step are to remove unnecessary mentions
   of "whatchanged" from our documentation and tests.  With these,
   we have fewer places that we need to adjust when the command gets
   truly removed.

 * Then we start to require that the "--i-still-use-this" option is
   passed from the command line.  This requires adjustment for tests
   that protect the behaviour of the command, as they must now pass
   the required option just like end-users.

 * The last two steps are for a future.  In order to make sure that
   we can cleanly ditch the feature at some future date by removing
   it from the build, test, and documentation when Git is built with
   WITH_BREAKING_CHANGES.  And finally we add "whatchanged" to the
   list of features to be removed in the BreakingChanges document.

Junio C Hamano (6):
  you-still-use-that??: help deprecating commands for removal
  doc: prepare for a world without whatchanged
  tests: prepare for a world without whatchanged
  whatchanged: require --i-still-use-this
  whatchanged: remove when built with WITH_BREAKING_CHANGES
  whatschanged: list it in BreakingChanges document

 Documentation/BreakingChanges.adoc           |  9 ++++++
 Documentation/MyFirstObjectWalk.adoc         |  4 +--
 Documentation/config/format.adoc             |  6 ++++
 Documentation/config/log.adoc                | 11 +++++--
 Documentation/git-whatchanged.adoc           | 10 ++++--
 Documentation/pretty-options.adoc            |  5 +++
 Documentation/rev-list-options.adoc          |  9 ++++--
 Documentation/technical/sparse-checkout.adoc |  2 +-
 Documentation/user-manual.adoc               |  2 +-
 builtin/log.c                                | 19 +++++++++++
 builtin/pack-redundant.c                     | 10 ++----
 git-compat-util.h                            |  2 ++
 git.c                                        |  2 ++
 t/t4013-diff-various.sh                      | 27 ++++++++++++++--
 t/t4202-log.sh                               | 34 ++++++++++++++------
 t/t5323-pack-redundant.sh                    |  5 +++
 t/t9300-fast-import.sh                       | 12 +++----
 t/t9301-fast-import-notes.sh                 |  2 +-
 usage.c                                      | 12 +++++++
 19 files changed, 146 insertions(+), 37 deletions(-)