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Re: [PATCH 12/15] use get_commit_buffer everywhere

From
Jeff King <peff@peff.net>
Date
Jun 10, 2014, 21:27 UTC
Message-ID
<20140610212753.GA15332@sigill.intra.peff.net>
In-Reply-To
<xmqqioo8agvo.fsf@gitster.dls.corp.google.com>
On Tue, Jun 10, 2014 at 09:06:35AM -0700, Junio C Hamano wrote:
> > So any call to strbuf_detach on the result would be disastrous.
> 
> You are right.  Where did this original crap come from X-<...

I do not know if that face means you actually looked at the history, but in case you did not...

It was added by Duy's 13f8b72 (Convert commit_tree() to take strbuf as message, 2011-12-15). However that was v2 of his patch. If you read the original thread, you can see that v1 passed a separate pointer/length pair, and was only changed after a reviewer-who-shall-not-be-named asked him to change it. ;)

Of course there were many people participating in the review, and none of us noticed it. I think it is simply a subtle bug.

Show 15 quoted lines
> > I feel like the most elegant solution is for create_notes_commit to take
> > a buf/len pair rather than a strbuf, but it unfortunately is just
> > feeding that to commit_tree. Adjusting that code path would affect quite
> > a few other spots.
> >
> > The other obvious option is actually populating the strbuf, but it feels
> > ugly to have to make a copy just to satisfy the function interface.
> >
> > Maybe a cast and a warning comment are the least evil thing, as below? I
> > dunno, it feels pretty wrong.
> 
> Yeah, it does feel wrong wrong wrong.  Perhaps this big comment
> would serve as a marker for a low-hanging fruit for somebody else to
> fix it, e.g. by using strbuf-add to make a copy, which would be the
> easiest and safest workaround?

I really think commit_tree is the culprit here. It doesn't actually want a strbuf at all, but takes one to make passing the pointer/len pair simpler. Fixing it turned out to be not _too_ disruptive, and it showed that there is another dubious use of strbuf_attach from a different caller.

I'll post my re-rolled series with those fixes in a moment.
-Peff
Previous: Junio C HamanoNext: Jeff King
Message 27 of 60 in “store length of commit->buffer”
  1. 0/15 store length of commit->bufferJeff King, Jun 9, 2014
  2. 01/15 alloc: include any-object allocations in alloc_reportJeff King, Jun 9, 2014
  3. 02/15 commit: push commit_index update into alloc_commit_nodeJeff King, Jun 9, 2014
  4. Junio C HamanoJun 10, 2014
  5. 03/15 do not create "struct commit" with xcallocJeff King, Jun 9, 2014
  6. Junio C HamanoJun 10, 2014
  7. Jeff KingJun 10, 2014
  8. 04/15 logmsg_reencode: return const bufferJeff King, Jun 9, 2014
  9. Eric SunshineJun 10, 2014
  10. 05/15 sequencer: use logmsg_reencode in get_messageJeff King, Jun 9, 2014
  11. Junio C HamanoJun 10, 2014
  12. Jeff KingJun 10, 2014
  13. 06/15 provide a helper to free commit bufferJeff King, Jun 9, 2014
  14. 07/15 provide a helper to set the commit bufferJeff King, Jun 9, 2014
  15. 08/15 provide helpers to access the commit bufferJeff King, Jun 9, 2014
  16. Eric SunshineJun 10, 2014
  17. 09/15 use get_cached_commit_buffer where appropriateJeff King, Jun 9, 2014
  18. 10/15 use get_commit_buffer to avoid duplicate codeJeff King, Jun 9, 2014
  19. Eric SunshineJun 10, 2014
  20. Jeff KingJun 10, 2014
  21. 11/15 convert logmsg_reencode to get_commit_bufferJeff King, Jun 9, 2014
  22. 12/15 use get_commit_buffer everywhereJeff King, Jun 9, 2014
  23. Junio C HamanoJun 9, 2014
  24. Jeff KingJun 10, 2014
  25. Jeff KingJun 10, 2014
  26. Junio C HamanoJun 10, 2014
  27. Jeff KingJun 10, 2014
  28. 13/15 commit-slab: provide a static initializerJeff King, Jun 9, 2014
  29. 14/15 commit: convert commit->buffer to a slabJeff King, Jun 9, 2014
  30. 15/15 commit: record buffer length in cacheJeff King, Jun 9, 2014
  31. Christian CouderJun 10, 2014
  32. Jeff KingJun 10, 2014
  33. Jeff KingJun 10, 2014
  34. Christian CouderJun 10, 2014
  35. 0/17 store length of commit->bufferJeff King, Jun 10, 2014
  36. 01/17 commit_tree: take a pointer/len pair rather than a const strbufJeff King, Jun 10, 2014
  37. 02/17 replace dangerous uses of strbuf_attachJeff King, Jun 10, 2014
  38. 03/17 alloc: include any-object allocations in alloc_reportJeff King, Jun 10, 2014
  39. 04/17 commit: push commit_index update into alloc_commit_nodeJeff King, Jun 10, 2014
  40. 05/17 do not create "struct commit" with xcallocJeff King, Jun 10, 2014
  41. 06/17 logmsg_reencode: return const bufferJeff King, Jun 10, 2014
  42. 07/17 sequencer: use logmsg_reencode in get_messageJeff King, Jun 10, 2014
  43. 08/17 provide a helper to free commit bufferJeff King, Jun 10, 2014
  44. Junio C HamanoJun 12, 2014
  45. Jeff KingJun 12, 2014
  46. Jeff KingJun 12, 2014
  47. 09/17 provide a helper to set the commit bufferJeff King, Jun 10, 2014
  48. 10/17 provide helpers to access the commit bufferJeff King, Jun 10, 2014
  49. 11/17 use get_cached_commit_buffer where appropriateJeff King, Jun 10, 2014
  50. 12/17 use get_commit_buffer to avoid duplicate codeJeff King, Jun 10, 2014
  51. 13/17 convert logmsg_reencode to get_commit_bufferJeff King, Jun 10, 2014
  52. 14/17 use get_commit_buffer everywhereJeff King, Jun 10, 2014
  53. 15/17 commit-slab: provide a static initializerJeff King, Jun 10, 2014
  54. Junio C HamanoJun 12, 2014
  55. Jeff KingJun 12, 2014
  56. 16/17 commit: convert commit->buffer to a slabJeff King, Jun 10, 2014
  57. 17/17 commit: record buffer length in cacheJeff King, Jun 10, 2014
  58. Jeff KingJun 10, 2014
  59. Junio C HamanoJun 12, 2014
  60. reuse cached commit buffer when parsing signaturesJeff King, Jun 13, 2014

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