[PATCH v5 00/35] Lockfile correctness and refactoring

Next iteration of my lockfile fixes and refactoring. Thanks to Torsten Bögershausen, Junio, Peff, Ronnie Sahlberg, and Johannes Sixt for their comments about v4.

I believe that this series addresses all of the comments from v1 [1], v2 [2], v3 [3], and v4 [4].

Changes since v4:

* Rebase to current master.

* Explain lock_file ownership and the point of its pid field.

* Correct the log message for

    "delete_ref_loose(): don't muck around in the lock_file's filename"

* Replace an assert() with a die("BUG:").

* Add a sanity check that lk->filename is empty before reusing a
  lock_file object.

* Initialize the length of lk->filename more intelligently.

* Rename trim_last_path_elm() to trim_last_path_component().

* Make some die() messages more informative.

* Add some sanity checks to commit_lock_file().

* Rename REF_NODEREF to REF_NO_DEREF.

* Rename some static functions:
  * remove_lock_file() -> remove_lock_files()
  * remove_lock_file_on_signal() -> remove_lock_files_on_signal()

* Add a function get_locked_file_path(), to isolate callers a bit more
  from the innards of lock_file.

There are some conflicts with branch rs/ref-transaction; I pushed my proposed merge of these two branches to

    https://github.com/mhagger/git.git lock-correctness-v5-rs-ref-transaction

[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 [4] http://thread.gmane.org/gmane.comp.version-control.git/256564

Michael Haggerty (35):
  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_component(): replace last_path_elm()
  Extract a function commit_lock_file_to()
  Rename LOCK_NODEREF to LOCK_NO_DEREF
  lockfile.c: rename static functions
  get_locked_file_path(): new function

 Documentation/technical/api-lockfile.txt |  72 +++++--
 builtin/commit.c                         |  16 +-
 builtin/merge.c                          |  15 +-
 builtin/reflog.c                         |   2 +-
 builtin/update-index.c                   |   2 +-
 cache.h                                  |  19 +-
 config.c                                 |  28 +--
 fast-import.c                            |   4 +-
 lockfile.c                               | 334 +++++++++++++++++++------------
 read-cache.c                             |  12 +-
 refs.c                                   |  29 +--
 shallow.c                                |   6 +-
 12 files changed, 334 insertions(+), 205 deletions(-)