[PATCH 0/3 v4] Make git log --follow find copies among unmodified files.

I have tried to make --follow to support finding copies among unmodified files. And the first patch is to fix a bug introduced by '--follow' and 'git log' combination.
We use the code:

    else if (--p->one->rename_used > 0)
        p->status = DIFF_STATUS_COPIED;

to detect copies and renames. So, if diffcore_std run more than one time, p->one->rename_used will be reduced to a 'R' from 'C'. And this patch will fix this by allowing diffcore_std can only run once before a diff_flush, which seems rationale for our code.

Bo Yang (3):
  Add a macro DIFF_QUEUE_CLEAR.
  Make diffcore_std only can run once before a diff_flush
  Make git log --follow find copies among unmodified files.

 Documentation/git-log.txt           |    2 +-
 diff.c                              |   21 ++++++++-----
 diffcore-break.c                    |    6 +--
 diffcore-pickaxe.c                  |    3 +-
 diffcore-rename.c                   |    3 +-
 diffcore.h                          |    7 ++++
 t/t4205-log-follow-harder-copies.sh |   56 +++++++++++++++++++++++++++++++++++
 tree-diff.c                         |    2 +-
 8 files changed, 82 insertions(+), 18 deletions(-)
 create mode 100755 t/t4205-log-follow-harder-copies.sh