git/list[1] front-page[2] threads[3] people[4] search[5] about
 

Re: [PATCH v2 11/25] object_array_remove_duplicates(): rewrite to reduce copying

From
Junio C Hamano <gitster@pobox.com>
Date
Jun 2, 2013, 21:02 UTC
Message-ID
<7vy5asmdji.fsf@alter.siamese.dyndns.org>
In-Reply-To
<51A7C146.6090605@alum.mit.edu>
Michael Haggerty <mhagger@alum.mit.edu> writes:
Show 28 quoted lines
>> The only caller of remove-duplicates is bundle.c, which gets many
>> starting points and end points from the command line and tries to be
>> nice by removing obvious duplicates, e.g.
>> 
>> 	git bundle create t.bundle master master
>> 
>> but I think its logic of deduping is wrong.  It runs dwim_ref() on
>> the incoming refs after the remove-duplicates call, so
>> 
>> 	git bundle create t.bundle master heads/mater
>> 
>> will end up with two copies of refs/heads/master.  To fix it, the
>> code must dedup the result of running dwim_ref(), and at that point,
>> there is no reason to call object_array_remove_duplicates().
>
> That sounds reasonable.
>
> I poked around this code a bit to understand what is going on, and it
> occurred to me that the object_array can include both positive and
> negative references, right?  And yet object_array_remove_duplicates()
> only considers names, not flags.  So it seems to me that if the deduping
> code would see the same reference twice, once positive and once
> negative, then it would throw an arbitrary one of them out, which would
> be wrong.
>
> But I couldn't provoke this situation, so perhaps setup_revisions()
> already specially treats combinations like "master ^master"?  (If that's
> true then why? and wouldn't it get confused by "master ^heads/master"?)

With "git bundle create t.bundle ^master master", you see two entries in revs.pending.objects[] but they are the same object and is already marked as uninteresting, so you will not see 'master' in the result.

This parsing loop predates the more recent revs->cmdline mechanism, that treats these two command line arguments as separate entities, so that we can more reliably tell what the real end-user input is.

Previous: Michael HaggertyNext: Michael Haggerty
Message 15 of 40 in “Remove assumptions about each_ref_fn arg lifetimes”
  1. 00/25 Remove assumptions about each_ref_fn arg lifetimesMichael Haggerty, May 25, 2013
  2. 01/25 describe: make own copy of refnameMichael Haggerty, May 25, 2013
  3. 02/25 fetch: make own copies of refnamesMichael Haggerty, May 25, 2013
  4. 03/25 add_rev_cmdline(): make a copy of the name argumentMichael Haggerty, May 25, 2013
  5. 04/25 builtin_diff_tree(): make it obvious that function wants two entriesMichael Haggerty, May 25, 2013
  6. 05/25 cmd_diff(): use an object_array for holding treesMichael Haggerty, May 25, 2013
  7. 06/25 cmd_diff(): rename local variable "list" -> "entry"Michael Haggerty, May 25, 2013
  8. 07/25 cmd_diff(): make it obvious which cases are exclusive of each otherMichael Haggerty, May 25, 2013
  9. 08/25 revision: split some overly-long linesMichael Haggerty, May 25, 2013
  10. 09/25 object_array: add function object_array_filter()Michael Haggerty, May 25, 2013
  11. 10/25 revision: use object_array_filter() in implementation of gc_boundary()Michael Haggerty, May 25, 2013
  12. 11/25 object_array_remove_duplicates(): rewrite to reduce copyingMichael Haggerty, May 25, 2013
  13. Junio C HamanoMay 29, 2013
  14. Michael HaggertyMay 30, 2013
  15. Junio C HamanoJun 2, 2013
  16. 12/25 fsck: don't put a void*-shaped peg in a char*-shaped holeMichael Haggerty, May 25, 2013
  17. 13/25 find_first_merges(): initialize merges variable using initializerMichael Haggerty, May 25, 2013
  18. 14/25 find_first_merges(): remove unnecessary codeMichael Haggerty, May 25, 2013
  19. 15/25 object_array_entry: fix memory handling of the name fieldMichael Haggerty, May 25, 2013
  20. Junio C HamanoMay 29, 2013
  21. 16/25 do_fetch(): reduce scope of peer_itemMichael Haggerty, May 25, 2013
  22. 17/25 do_fetch(): clean up existing_refs before exitingMichael Haggerty, May 25, 2013
  23. 18/25 add_existing(): do not retain a reference to sha1Michael Haggerty, May 25, 2013
  24. 19/25 show_head_ref(): do not shadow name of argumentMichael Haggerty, May 25, 2013
  25. 20/25 show_head_ref(): rename first parameter to "refname"Michael Haggerty, May 25, 2013
  26. 21/25 string_list_add_one_ref(): rename first parameter to "refname"Michael Haggerty, May 25, 2013
  27. 22/25 string_list_add_refs_by_glob(): add a comment about memory managementMichael Haggerty, May 25, 2013
  28. Thomas RastMay 29, 2013
  29. Michael HaggertyMay 30, 2013
  30. 22/25 fixup! string_list_add_refs_by_glob(): add a comment about memory managementMichael Haggerty, May 30, 2013
  31. Junio C HamanoJun 3, 2013
  32. 23/25 exclude_existing(): set existing_refs.strdup_stringsMichael Haggerty, May 25, 2013
  33. 24/25 register_ref(): make a copy of the bad reference SHA-1Michael Haggerty, May 25, 2013
  34. Junio C HamanoMay 29, 2013
  35. Michael HaggertyMay 30, 2013
  36. Philip OakleyMay 30, 2013
  37. 25/25 refs: document the lifetime of the args passed to each_ref_fnMichael Haggerty, May 25, 2013
  38. Junio C HamanoMay 29, 2013
  39. Thomas RastMay 29, 2013
  40. Michael HaggertyMay 30, 2013

Read the whole thread, see it on lore, or plain text.

$ cat FOOTERMessages come from the public archive at lore.kernel.org/git, fetched every hour. The front page is chosen and written each morning by an AI editor and can be wrong; the threads themselves are the record. About and API. For agents: an MCP server at https://gitlist.dev/mcp, and any thread, story or person page as Markdown by adding .md to its URL (or sending Accept: text/markdown). Details in /llms.txt.