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Re: [PATCH v7 09/38] lock_file(): always initialize and register lock_file object

From
Michael Haggerty <mhagger@alum.mit.edu>
Date
Oct 1, 2014, 11:38 UTC
Message-ID
<542BE7CA.5060902@alum.mit.edu>
In-Reply-To
<542BE535.3040500@web.de>
On 10/01/2014 01:27 PM, René Scharfe wrote:
Show 19 quoted lines
> Am 01.10.2014 um 12:28 schrieb Michael Haggerty:
>> The purpose of this patch is to make the state diagram for lock_file
>> objects simpler and deterministic.
>>
>> If locking fails, lock_file() sometimes leaves the lock_file object
>> partly initialized, but sometimes not. It sometimes registers the
>> object in lock_file_list, but sometimes not. This makes the state
>> diagram for lock_file objects effectively indeterministic and hard to
>> reason about. A future patch will also change the filename field into
>> a strbuf, which needs more involved initialization, so it will become
>> even more important that the state of a lock_file object is
>> well-defined after a failed attempt to lock.
>>
>> The ambiguity doesn't currently have any ill effects, because
>> lock_file objects cannot be removed from the lock_file_list anyway.
>> But to make it easier to document and reason about the code, make this
>> behavior inconsistent: *always* initialize the lock_file object and
> 
> s/incon/con/, certainly?
Yes, thanks.

Junio, if another reroll is not necessary, would you mind fixing this when applying?

Michael
-- 
Michael Haggerty
mhagger@alum.mit.edu
Previous: René ScharfeNext: Junio C Hamano
Message 12 of 43 in “Lockfile correctness and refactoring”
  1. 00/38 Lockfile correctness and refactoringMichael Haggerty, Oct 1, 2014
  2. 01/38 unable_to_lock_die(): rename function from unable_to_lock_index_die()Michael Haggerty, Oct 1, 2014
  3. 02/38 api-lockfile: revise and expand the documentationMichael Haggerty, Oct 1, 2014
  4. 03/38 close_lock_file(): exit (successfully) if file is already closedMichael Haggerty, Oct 1, 2014
  5. 04/38 rollback_lock_file(): do not clear filename redundantlyMichael Haggerty, Oct 1, 2014
  6. 05/38 rollback_lock_file(): exit early if lock is not activeMichael Haggerty, Oct 1, 2014
  7. 06/38 rollback_lock_file(): set fd to -1Michael Haggerty, Oct 1, 2014
  8. 07/38 lockfile: unlock file if lockfile permissions cannot be adjustedMichael Haggerty, Oct 1, 2014
  9. 08/38 hold_lock_file_for_append(): release lock on errorsMichael Haggerty, Oct 1, 2014
  10. 09/38 lock_file(): always initialize and register lock_file objectMichael Haggerty, Oct 1, 2014
  11. René ScharfeOct 1, 2014
  12. Michael HaggertyOct 1, 2014
  13. Junio C HamanoOct 1, 2014
  14. 10/38 lockfile.c: document the various states of lock_file objectsMichael Haggerty, Oct 1, 2014
  15. 11/38 cache.h: define constants LOCK_SUFFIX and LOCK_SUFFIX_LENMichael Haggerty, Oct 1, 2014
  16. 12/38 delete_ref_loose(): don't muck around in the lock_file's filenameMichael Haggerty, Oct 1, 2014
  17. 13/38 prepare_index(): declare return value to be (const char *)Michael Haggerty, Oct 1, 2014
  18. 14/38 lock_file(): exit early if lockfile cannot be openedMichael Haggerty, Oct 1, 2014
  19. 15/38 remove_lock_file(): call rollback_lock_file()Michael Haggerty, Oct 1, 2014
  20. 16/38 commit_lock_file(): inline temporary variableMichael Haggerty, Oct 1, 2014
  21. 17/38 commit_lock_file(): die() if called for unlocked lockfile objectMichael Haggerty, Oct 1, 2014
  22. 18/38 close_lock_file(): if close fails, roll backMichael Haggerty, Oct 1, 2014
  23. 19/38 commit_lock_file(): rollback lock file on failure to renameMichael Haggerty, Oct 1, 2014
  24. 20/38 api-lockfile: document edge casesMichael Haggerty, Oct 1, 2014
  25. 21/38 dump_marks(): remove a redundant call to rollback_lock_file()Michael Haggerty, Oct 1, 2014
  26. 22/38 git_config_set_multivar_in_file(): avoid call to rollback_lock_file()Michael Haggerty, Oct 1, 2014
  27. 23/38 lockfile: avoid transitory invalid statesMichael Haggerty, Oct 1, 2014
  28. 24/38 struct lock_file: declare some fields volatileMichael Haggerty, Oct 1, 2014
  29. 25/38 try_merge_strategy(): remove redundant lock_file allocationMichael Haggerty, Oct 1, 2014
  30. 26/38 try_merge_strategy(): use a statically-allocated lock_file objectMichael Haggerty, Oct 1, 2014
  31. 27/38 commit_lock_file(): use a strbuf to manage temporary spaceMichael Haggerty, Oct 1, 2014
  32. 28/38 Change lock_file::filename into a strbufMichael Haggerty, Oct 1, 2014
  33. 29/38 resolve_symlink(): use a strbuf for internal scratch spaceMichael Haggerty, Oct 1, 2014
  34. 30/38 resolve_symlink(): take a strbuf parameterMichael Haggerty, Oct 1, 2014
  35. 31/38 trim_last_path_component(): replace last_path_elm()Michael Haggerty, Oct 1, 2014
  36. 32/38 Extract a function commit_lock_file_to()Michael Haggerty, Oct 1, 2014
  37. 33/38 Rename LOCK_NODEREF to LOCK_NO_DEREFMichael Haggerty, Oct 1, 2014
  38. 34/38 lockfile.c: rename static functionsMichael Haggerty, Oct 1, 2014
  39. 35/38 get_locked_file_path(): new functionMichael Haggerty, Oct 1, 2014
  40. 36/38 hold_lock_file_for_append(): restore errno before returningMichael Haggerty, Oct 1, 2014
  41. 37/38 Move read_index() definition to read-cache.cMichael Haggerty, Oct 1, 2014
  42. 38/38 lockfile.h: extract new header file for the functions in lockfile.cMichael Haggerty, Oct 1, 2014
  43. Junio C HamanoOct 1, 2014

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