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Re: [PATCH 0/17] removing questionable uses of git_path

From
Junio C Hamano <gitster@pobox.com>
Date
Aug 10, 2015, 17:31 UTC
Message-ID
<xmqqr3nbuk23.fsf@gitster.dls.corp.google.com>
In-Reply-To
<20150810092731.GA9027@sigill.intra.peff.net>
Jeff King <peff@peff.net> writes:
> The problem is that git_path uses a static buffer that gets overwritten
> by subsequent calls.

As the rotating static buffer pattern used in get_pathname() was modeled after sha1_to_hex(), we have the same issue there. They are troubles waiting to happen unless the callers are careful.

> producing a fairly tame-looking set of function calls. It's OK to pass
> the result of git_path() to a system call, or something that is a thin
> wrapper around one (e.g., strbuf_read_file).

That is a short and good rule to follow, but the problem is that not everybody has good taste to interpret the above rule and apply it with an eye toward maintainability X-<.

Show 21 quoted lines
> Along the way, there are a few cleanups (e.g., I polished off the recent
> hold_lock_file_for_append topic which was on the list, as it had some
> problematic calls).
>
>   [01/17]: cache.h: clarify documentation for git_path, et al
>   [02/17]: cache.h: complete set of git_path_submodule helpers
>   [03/17]: t5700: modernize style
>   [04/17]: add_to_alternates_file: don't add duplicate entries
>   [05/17]: remove hold_lock_file_for_append
>   [06/17]: prefer git_pathdup to git_path in some possibly-dangerous cases
>   [07/17]: prefer mkpathdup to mkpath in assignments
>   [08/17]: remote.c: drop extraneous local variable from migrate_file
>   [09/17]: refs.c: remove extra git_path calls from read_loose refs
>   [10/17]: path.c: drop git_path_submodule
>   [11/17]: refs.c: simplify strbufs in reflog setup and writing
>   [12/17]: refs.c: avoid repeated git_path calls in rename_tmp_log
>   [13/17]: refs.c: avoid git_path assignment in lock_ref_sha1_basic
>   [14/17]: refs.c: remove_empty_directories can take a strbuf
>   [15/17]: find_hook: keep our own static buffer
>   [16/17]: get_repo_path: refactor path-allocation
>   [17/17]: memoize common git-path "constant" files
Nice.  Thanks.
Previous: Michael HaggertyNext: Jeff King
Message 32 of 34 in “removing questionable uses of git_path”
  1. 0/17 removing questionable uses of git_pathJeff King, Aug 10, 2015
  2. 01/17 cache.h: clarify documentation for git_path, et alJeff King, Aug 10, 2015
  3. 02/17 cache.h: complete set of git_path_submodule helpersJeff King, Aug 10, 2015
  4. 03/17 t5700: modernize styleJeff King, Aug 10, 2015
  5. 04/17 add_to_alternates_file: don't add duplicate entriesJeff King, Aug 10, 2015
  6. Michael HaggertyAug 11, 2015
  7. Jeff KingAug 11, 2015
  8. 05/17 remove hold_lock_file_for_appendJeff King, Aug 10, 2015
  9. Junio C HamanoAug 10, 2015
  10. Jeff KingAug 11, 2015
  11. 06/17 prefer git_pathdup to git_path in some possibly-dangerous casesJeff King, Aug 10, 2015
  12. 07/17 prefer mkpathdup to mkpath in assignmentsJeff King, Aug 10, 2015
  13. 08/17 remote.c: drop extraneous local variable from migrate_fileJeff King, Aug 10, 2015
  14. 09/17 refs.c: remove extra git_path calls from read_loose_refsJeff King, Aug 10, 2015
  15. 10/17 path.c: drop git_path_submoduleJeff King, Aug 10, 2015
  16. Junio C HamanoAug 10, 2015
  17. Junio C HamanoAug 10, 2015
  18. Junio C HamanoAug 10, 2015
  19. Jeff KingAug 11, 2015
  20. 11/17 refs.c: simplify strbufs in reflog setup and writingJeff King, Aug 10, 2015
  21. Michael HaggertyAug 10, 2015
  22. Jeff KingAug 10, 2015
  23. 12/17 refs.c: avoid repeated git_path calls in rename_tmp_logJeff King, Aug 10, 2015
  24. 13/17 refs.c: avoid git_path assignment in lock_ref_sha1_basicJeff King, Aug 10, 2015
  25. 14/17 refs.c: remove_empty_directories can take a strbufJeff King, Aug 10, 2015
  26. 15/17 find_hook: keep our own static bufferJeff King, Aug 10, 2015
  27. 16/17 get_repo_path: refactor path-allocationJeff King, Aug 10, 2015
  28. 17/17 memoize common git-path "constant" filesJeff King, Aug 10, 2015
  29. Michael HaggertyAug 10, 2015
  30. Jeff KingAug 10, 2015
  31. Michael HaggertyAug 10, 2015
  32. Junio C HamanoAug 10, 2015
  33. Jeff KingAug 10, 2015
  34. Duy NguyenAug 15, 2015

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