[PATCH v3 00/30] Create a reference backend for packed refs

This is v3 of a patch series creating a `packed_ref_store` reference backend. Thanks to Peff and Junio for their comments about v2 [1].

Changes since v2:

* Delete some debugging `cat` commands in t1408.

* Add some tests of reading packed-refs files with bogus contents.

* When reporting corruption in packed-refs files, distinguish between
  unterminated lines and other corruption.

* Fixed a typo in a commit message.

This patch series can also be obtained from my GitHub fork [2] as branch packed-ref-store.

Michael

[1] v1: http://public-inbox.org/git/cover.1497534157.git.mhagger@alum.mit.edu/
    v2: http://public-inbox.org/git/cover.1498200513.git.mhagger@alum.mit.edu/
[2] https://github.com/mhagger/git

Junio C Hamano (1):
  t1408: add a test of stale packed refs covered by loose refs

Michael Haggerty (29):
  add_packed_ref(): teach function to overwrite existing refs
  packed_ref_store: new struct
  packed_ref_store: move `packed_refs_path` here
  packed_ref_store: move `packed_refs_lock` member here
  clear_packed_ref_cache(): take a `packed_ref_store *` parameter
  validate_packed_ref_cache(): take a `packed_ref_store *` parameter
  get_packed_ref_cache(): take a `packed_ref_store *` parameter
  get_packed_refs(): take a `packed_ref_store *` parameter
  add_packed_ref(): take a `packed_ref_store *` parameter
  lock_packed_refs(): take a `packed_ref_store *` parameter
  commit_packed_refs(): take a `packed_ref_store *` parameter
  rollback_packed_refs(): take a `packed_ref_store *` parameter
  get_packed_ref(): take a `packed_ref_store *` parameter
  repack_without_refs(): take a `packed_ref_store *` parameter
  packed_peel_ref(): new function, extracted from `files_peel_ref()`
  packed_ref_store: support iteration
  packed_read_raw_ref(): new function, replacing `resolve_packed_ref()`
  packed-backend: new module for handling packed references
  packed_ref_store: make class into a subclass of `ref_store`
  commit_packed_refs(): report errors rather than dying
  commit_packed_refs(): use a staging file separate from the lockfile
  packed_refs_lock(): function renamed from lock_packed_refs()
  packed_refs_lock(): report errors via a `struct strbuf *err`
  packed_refs_unlock(), packed_refs_is_locked(): new functions
  clear_packed_ref_cache(): don't protest if the lock is held
  commit_packed_refs(): remove call to `packed_refs_unlock()`
  repack_without_refs(): don't lock or unlock the packed refs
  t3210: add some tests of bogus packed-refs file contents
  read_packed_refs(): die if `packed-refs` contains bogus data

 Makefile               |   1 +
 refs.c                 |  18 +
 refs/files-backend.c   | 631 ++++-------------------------------
 refs/packed-backend.c  | 872 +++++++++++++++++++++++++++++++++++++++++++++++++
 refs/packed-backend.h  |  25 ++
 refs/refs-internal.h   |  10 +
 t/t1408-packed-refs.sh |  42 +++
 t/t3210-pack-refs.sh   |  27 ++
 8 files changed, 1066 insertions(+), 560 deletions(-)
 create mode 100644 refs/packed-backend.c
 create mode 100644 refs/packed-backend.h
 create mode 100755 t/t1408-packed-refs.sh