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Re: [PATCH v2 28/51] refs.c: rename ref_array -> ref_dir

From
Jeff King <peff@peff.net>
Date
Dec 15, 2011, 08:37 UTC
Message-ID
<20111215083732.GA5958@sigill.intra.peff.net>
In-Reply-To
<4EE9AD7C.2050605@alum.mit.edu>
On Thu, Dec 15, 2011 at 09:19:08AM +0100, Michael Haggerty wrote:
Show 6 quoted lines
> Now I'm looking at the uses of extra_refs in git-clone.  One thing it
> does is add some extra refs then write them to the packed-refs file.  I
> still have to dig into it, but this seems strange.  If the refs are
> being written to packed-refs, it seems like they must be real (not
> extra) refs, or perhaps are just about to become real refs as part of
> the clone.  Or is something more egregious is going on?

I think what is happening is that the extra_refs system is doing double duty here. If you do:

  git clone --reference $local $origin
then the code does something like:
  1. Add all of the refs in $local are added to extra_refs, because we
     want to advertise them during the pack fetch (see add_one_reference,
     called through setup_reference at l. 626).
  2. We then get the list of remote refs from $origin and store them in
     mapped_refs (ll. 657-658). The fetch uses the extra refs from (1).
  3. We call clear_extra_refs to drop those temporary refs (l. 663).
  4. We call write_remote_refs (l. 664), which adds all of the
     mapped_refs from (2) to extra_refs, then calls pack_refs which will
     pack all of the existing refs (of which there should be none, I
     would think), including extras (i.e., all the stuff we just
     cloned).
     Afterwards we clear_extra_refs again, though I think that is
     probably unnecessary.

Keeping the ".have" sha1s out of extra_refs would make this a lot clearer. Arguably it would also be better to have some way to just pass the set of mapped_refs to pack_refs, instead of shoving them in the global extra_refs and relying on pack_refs to find them there.

-Peff
Previous: Michael HaggertyNext: Michael Haggerty
Message 49 of 79 in “ref-api-C and ref-api-D re-roll”
  1. 00/51 ref-api-C and ref-api-D re-rollmhagger@alum.mit.edu, Dec 12, 2011
  2. 01/51 struct ref_entry: document name membermhagger@alum.mit.edu, Dec 12, 2011
  3. 02/51 refs: rename "refname" variablesmhagger@alum.mit.edu, Dec 12, 2011
  4. Junio C HamanoDec 13, 2011
  5. 03/51 refs: rename parameters result -> sha1mhagger@alum.mit.edu, Dec 12, 2011
  6. 04/51 clear_ref_array(): rename from free_ref_array()mhagger@alum.mit.edu, Dec 12, 2011
  7. 05/51 is_refname_available(): remove the "quiet" argumentmhagger@alum.mit.edu, Dec 12, 2011
  8. 06/51 parse_ref_line(): add docstringmhagger@alum.mit.edu, Dec 12, 2011
  9. 07/51 add_ref(): add docstringmhagger@alum.mit.edu, Dec 12, 2011
  10. 08/51 is_dup_ref(): extract function from sort_ref_array()mhagger@alum.mit.edu, Dec 12, 2011
  11. Jeff KingDec 12, 2011
  12. Michael HaggertyDec 12, 2011
  13. Junio C HamanoDec 12, 2011
  14. Junio C HamanoDec 12, 2011
  15. Michael HaggertyDec 13, 2011
  16. Michael HaggertyDec 13, 2011
  17. 09/51 refs: change signatures of get_packed_refs() and get_loose_refs()mhagger@alum.mit.edu, Dec 12, 2011
  18. 10/51 get_ref_dir(): change signaturemhagger@alum.mit.edu, Dec 12, 2011
  19. 11/51 resolve_gitlink_ref(): improve docstringmhagger@alum.mit.edu, Dec 12, 2011
  20. 12/51 Pass a (ref_cache *) to the resolve_gitlink_*() helper functionsmhagger@alum.mit.edu, Dec 12, 2011
  21. 13/51 resolve_gitlink_ref_recursive(): change to work with struct ref_cachemhagger@alum.mit.edu, Dec 12, 2011
  22. 14/51 repack_without_ref(): remove temporarymhagger@alum.mit.edu, Dec 12, 2011
  23. 15/51 create_ref_entry(): extract function from add_ref()mhagger@alum.mit.edu, Dec 12, 2011
  24. 16/51 add_ref(): take a (struct ref_entry *) parametermhagger@alum.mit.edu, Dec 12, 2011
  25. 17/51 do_for_each_ref(): correctly terminate while processesing extra_refsmhagger@alum.mit.edu, Dec 12, 2011
  26. Junio C HamanoDec 12, 2011
  27. 18/51 do_for_each_ref_in_array(): new functionmhagger@alum.mit.edu, Dec 12, 2011
  28. 19/51 do_for_each_ref_in_arrays(): new functionmhagger@alum.mit.edu, Dec 12, 2011
  29. 20/51 repack_without_ref(): reimplement using do_for_each_ref_in_array()mhagger@alum.mit.edu, Dec 12, 2011
  30. Junio C HamanoDec 12, 2011
  31. 21/51 names_conflict(): new function, extracted from is_refname_available()mhagger@alum.mit.edu, Dec 12, 2011
  32. 22/51 names_conflict(): simplify implementationmhagger@alum.mit.edu, Dec 12, 2011
  33. 23/51 is_refname_available(): reimplement using do_for_each_ref_in_array()mhagger@alum.mit.edu, Dec 12, 2011
  34. 24/51 refs.c: reorder definitions more logicallymhagger@alum.mit.edu, Dec 12, 2011
  35. 25/51 free_ref_entry(): new functionmhagger@alum.mit.edu, Dec 12, 2011
  36. 26/51 check_refname_component(): return 0 for zero-length componentsmhagger@alum.mit.edu, Dec 12, 2011
  37. 27/51 struct ref_entry: nest the value part in a unionmhagger@alum.mit.edu, Dec 12, 2011
  38. 28/51 refs.c: rename ref_array -> ref_dirmhagger@alum.mit.edu, Dec 12, 2011
  39. Junio C HamanoDec 13, 2011
  40. Michael HaggertyDec 13, 2011
  41. Junio C HamanoDec 13, 2011
  42. Michael HaggertyDec 13, 2011
  43. Junio C HamanoDec 13, 2011
  44. Michael HaggertyDec 13, 2011
  45. Junio C HamanoDec 13, 2011
  46. Junio C HamanoDec 14, 2011
  47. Jeff KingDec 14, 2011
  48. Michael HaggertyDec 15, 2011
  49. Jeff KingDec 15, 2011
  50. Michael HaggertyJan 17, 2012
  51. Michael HaggertyFeb 10, 2012
  52. Jeff KingFeb 10, 2012
  53. Junio C HamanoFeb 10, 2012
  54. Michael HaggertyFeb 11, 2012
  55. 29/51 refs: store references hierarchicallymhagger@alum.mit.edu, Dec 12, 2011
  56. 30/51 sort_ref_dir(): do not sort if already sortedmhagger@alum.mit.edu, Dec 12, 2011
  57. Junio C HamanoDec 12, 2011
  58. 31/51 refs: sort ref_dirs lazilymhagger@alum.mit.edu, Dec 12, 2011
  59. 32/51 do_for_each_ref(): only iterate over the subtree that was requestedmhagger@alum.mit.edu, Dec 12, 2011
  60. 33/51 get_ref_dir(): keep track of the current ref_dirmhagger@alum.mit.edu, Dec 12, 2011
  61. 34/51 refs: wrap top-level ref_dirs in ref_entriesmhagger@alum.mit.edu, Dec 12, 2011
  62. 35/51 get_packed_refs(): return (ref_entry *) instead of (ref_dir *)mhagger@alum.mit.edu, Dec 12, 2011
  63. 36/51 get_loose_refs(): return (ref_entry *) instead of (ref_dir *)mhagger@alum.mit.edu, Dec 12, 2011
  64. 37/51 is_refname_available(): take (ref_entry *) instead of (ref_dir *)mhagger@alum.mit.edu, Dec 12, 2011
  65. 38/51 find_ref(): take (ref_entry *) instead of (ref_dir *)mhagger@alum.mit.edu, Dec 12, 2011
  66. 39/51 read_packed_refs(): take (ref_entry *) instead of (ref_dir *)mhagger@alum.mit.edu, Dec 12, 2011
  67. 40/51 add_ref(): take (ref_entry *) instead of (ref_dir *)mhagger@alum.mit.edu, Dec 12, 2011
  68. 41/51 find_containing_direntry(): use (ref_entry *) instead of (ref_dir *)mhagger@alum.mit.edu, Dec 12, 2011
  69. 42/51 search_ref_dir(): take (ref_entry *) instead of (ref_dir *)mhagger@alum.mit.edu, Dec 12, 2011
  70. 43/51 add_entry(): take (ref_entry *) instead of (ref_dir *)mhagger@alum.mit.edu, Dec 12, 2011
  71. 44/51 do_for_each_ref_in_dir*(): take (ref_entry *) instead of (ref_dir *)mhagger@alum.mit.edu, Dec 12, 2011
  72. 45/51 sort_ref_dir(): take (ref_entry *) instead of (ref_dir *)mhagger@alum.mit.edu, Dec 12, 2011
  73. 46/51 struct ref_dir: store a reference to the enclosing ref_cachemhagger@alum.mit.edu, Dec 12, 2011
  74. 47/51 read_loose_refs(): take a (ref_entry *) as argumentmhagger@alum.mit.edu, Dec 12, 2011
  75. 48/51 refs: read loose references lazilymhagger@alum.mit.edu, Dec 12, 2011
  76. 49/51 is_refname_available(): query only possibly-conflicting referencesmhagger@alum.mit.edu, Dec 12, 2011
  77. 50/51 read_packed_refs(): keep track of the directory being worked inmhagger@alum.mit.edu, Dec 12, 2011
  78. 51/51 repack_without_ref(): call clear_packed_ref_cache()mhagger@alum.mit.edu, Dec 12, 2011
  79. Junio C HamanoDec 12, 2011

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