[PATCH v4 00/32] Lockfile correctness and refactoring

Sorry for the long delay since v3. This version mostly cleans up a couple more places where the lockfile object was left in an ill-defined state. Thanks to Johannes Sixt and Torsten Bögershausen for their review of v3.

I believe that this series addresses all of the comments from v1 [1], v2 [2], and v3 [3].

This series applies to the current "master". There is a trivial conflict between these changes and "next", and a few not-too-serious conflicts between these changes and Ronnie's reference-related series in "pu". I've figured out how to resolve the conflicts locally. Is there some form in which I can put the conflict resolution that would help you?

Changes since v3:

* Rebase to the current master, including adjusting the patch series
  for 93dcaea2 (addition of reopen_lock_file()).

* Perform the internal consistency check right away in
  commit_lock_file(), rather than after possibly having closed the
  file.

* Improve the explanation of the rationale for marking lock_file
  fields volatile.

* Fix comments that still referred to lock_file::filename[0] even
  though it is now a strbuf.

* Change rollback_lock_file() to exit early if the lock is not active
  (rather than nesting the rest of the function in an "if" statement).

* Fix Johannes's email address in the trailers.

* Extract a function commit_lock_file_to(lk, filename) and delegate to
  it from commit_lock_file() and commit_locked_index() so that the
  latter gets the benefit of the improvements in this patch series.

[1] http://thread.gmane.org/gmane.comp.version-control.git/245609 [2] http://thread.gmane.org/gmane.comp.version-control.git/245801 [3] http://thread.gmane.org/gmane.comp.version-control.git/246222

Michael Haggerty (32):
  unable_to_lock_die(): rename function from unable_to_lock_index_die()
  api-lockfile: expand the documentation
  rollback_lock_file(): do not clear filename redundantly
  rollback_lock_file(): exit early if lock is not active
  rollback_lock_file(): set fd to -1
  lockfile: unlock file if lockfile permissions cannot be adjusted
  hold_lock_file_for_append(): release lock on errors
  lock_file(): always add lock_file object to lock_file_list
  lockfile.c: document the various states of lock_file objects
  cache.h: define constants LOCK_SUFFIX and LOCK_SUFFIX_LEN
  delete_ref_loose(): don't muck around in the lock_file's filename
  prepare_index(): declare return value to be (const char *)
  write_packed_entry_fn(): convert cb_data into a (const int *)
  lock_file(): exit early if lockfile cannot be opened
  remove_lock_file(): call rollback_lock_file()
  commit_lock_file(): inline temporary variable
  commit_lock_file(): die() if called for unlocked lockfile object
  commit_lock_file(): if close fails, roll back
  commit_lock_file(): rollback lock file on failure to rename
  api-lockfile: document edge cases
  dump_marks(): remove a redundant call to rollback_lock_file()
  git_config_set_multivar_in_file(): avoid call to rollback_lock_file()
  lockfile: avoid transitory invalid states
  struct lock_file: declare some fields volatile
  try_merge_strategy(): remove redundant lock_file allocation
  try_merge_strategy(): use a statically-allocated lock_file object
  commit_lock_file(): use a strbuf to manage temporary space
  Change lock_file::filename into a strbuf
  resolve_symlink(): use a strbuf for internal scratch space
  resolve_symlink(): take a strbuf parameter
  trim_last_path_elm(): replace last_path_elm()
  Extract a function commit_lock_file_to()

 Documentation/technical/api-lockfile.txt |  67 +++++--
 builtin/commit.c                         |  16 +-
 builtin/merge.c                          |  15 +-
 builtin/reflog.c                         |   2 +-
 builtin/update-index.c                   |   2 +-
 cache.h                                  |  16 +-
 config.c                                 |  28 +--
 fast-import.c                            |   4 +-
 lockfile.c                               | 299 ++++++++++++++++++-------------
 read-cache.c                             |  12 +-
 refs.c                                   |  29 +--
 shallow.c                                |   6 +-
 12 files changed, 296 insertions(+), 200 deletions(-)