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Re: [PATCH 0/3] null sha1 in trees

From
Jeff King <peff@peff.net>
Date
Jul 30, 2012, 15:42 UTC
Message-ID
<20120730154214.GA16701@sigill.intra.peff.net>
In-Reply-To
<7v8ve2uscw.fsf@alter.siamese.dyndns.org>
On Sun, Jul 29, 2012 at 03:15:11PM -0700, Junio C Hamano wrote:
> All looked reasonable, even though I'd want to read the
> surrounding codepath over for 2/3 a few more times.
> 
> Will queue; thanks.

Yeah, 2/3 is the one that gives me the most pause. I originally assumed we would never want to put a null-sha1 entry into the in-core index, but that turned out to be very wrong. So I softened my assumption to "we would never want to put a null-sha1 entry on disk". Which seems like the right thing to me and passes the test suite, but there might be an unexercised code path in there.

In an ideal world, I would trace each code path that inserts a cache entry all the way back to its original sha1, but when I tried it turned out too complex. The educated-guess-and-see-if-it-passes-tests approach to coding does not make me happy, but I don't see a good alternative.

Patch 1 is a pure bug-fix, and it would be nice for it to make it onto a maint- track or into 1.7.12 (though I can't guarantee that I got it 100% right, I am confident that it is at least trying to do the right thing, and any fixes would be incremental on top). The other two should be fine to cook longer and go in post-1.7.12.

-Peff
Previous: Junio C Hamano
Message 22 of 22 in “null sha1 in trees”
  1. 0/3 null sha1 in treesJeff King, Jul 28, 2012
  2. 1/3 diff: do not use null sha1 as a sentinel valueJeff King, Jul 28, 2012
  3. 2/3 do not write null sha1s to on-disk indexJeff King, Jul 28, 2012
  4. Jonathan NiederDec 29, 2012
  5. Jeff KingDec 29, 2012
  6. Jonathan NiederDec 29, 2012
  7. Jeff KingDec 29, 2012
  8. Jonathan NiederDec 29, 2012
  9. Jeff KingDec 29, 2012
  10. [BUG] two-way read-tree can write null sha1s into indexJeff King, Dec 29, 2012
  11. Junio C HamanoJan 1, 2013
  12. Jeff KingJan 3, 2013
  13. Junio C HamanoJan 3, 2013
  14. Jeff KingJan 3, 2013
  15. Junio C HamanoJan 3, 2013
  16. Jeff KingJan 3, 2013
  17. Junio C HamanoJan 3, 2013
  18. Jeff KingJan 7, 2013
  19. Jonathan NiederDec 29, 2012
  20. 3/3 fsck: detect null sha1 in tree entriesJeff King, Jul 28, 2012
  21. Junio C HamanoJul 29, 2012
  22. Jeff KingJul 30, 2012

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