[PATCH v2 0/8] object_id part 4

This series is part 4 in a series of conversions to replace instances of unsigned char [20] with struct object_id. Most of this series touches the merge-recursive code.

New in this series is the use of Coccinelle (http://coccinelle.lip6.fr/) semantic patches. These semantic patches can make automatic transformations to C source code for cleanup or refactoring reasons.

This series introduces a set of transforms for the struct object_id transition, cleans up some existing code with them, and applies a small number of semantic patches to transform parts of the merge-recursive code. Some manual refactoring work follows.

Note that in the patches created with the semantic patches, the only manual change was the definition of the struct member. Opinions on whether this is a viable technique for further work to ease both the creation and review of patches are of course welcomed.

The testsuite continues to pass at each step, and this series rebases cleanly on both pu and next.

I moved the Coccinelle transforms to contrib/examples/coccinelle, but if it's decided that the Coccinelle transforms simply don't belong in the repository, it's fine to simply drop the first patch (and maybe fix up the commit messages). I can create a GitHub Gist and let reviewers refer to that at their convenience.

Changes from v1:
* Move the object ID transformations to contrib/examples/coccinelle.
* Add a README to that folder explaining what they are.
* Adjust the Coccinelle patches to transform plain structs before
  pointers to structs to avoid misconversions.  This addresses the issue
  that Peff caught originally.

brian m. carlson (8):
  Add basic Coccinelle transforms.
  Apply object_id Coccinelle transformations.
  Convert struct diff_filespec to struct object_id
  Rename struct diff_filespec's sha1_valid member.
  merge-recursive: convert struct stage_data to use object_id
  merge-recursive: convert struct merge_file_info to object_id
  merge-recursive: convert leaf functions to use struct object_id
  merge-recursive: convert merge_recursive_generic to object_id

 bisect.c                                    |   2 +-
 builtin/blame.c                             |   6 +-
 builtin/fast-export.c                       |  10 +-
 builtin/merge-recursive.c                   |  20 +-
 builtin/merge.c                             |  13 +-
 builtin/reset.c                             |   4 +-
 combine-diff.c                              |  14 +-
 contrib/examples/coccinelle/README          |   2 +
 contrib/examples/coccinelle/object_id.cocci |  83 ++++++++
 diff.c                                      |  95 +++++----
 diffcore-break.c                            |   4 +-
 diffcore-rename.c                           |  16 +-
 diffcore.h                                  |   4 +-
 line-log.c                                  |  12 +-
 merge-recursive.c                           | 310 ++++++++++++++--------------
 merge-recursive.h                           |   6 +-
 notes-merge.c                               |  42 ++--
 refs/files-backend.c                        |   4 +-
 submodule.c                                 |   4 +-
 wt-status.c                                 |   3 +-
 20 files changed, 378 insertions(+), 276 deletions(-)
 create mode 100644 contrib/examples/coccinelle/README
 create mode 100644 contrib/examples/coccinelle/object_id.cocci