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SHA1 collision in production repo?! (probably not)

From
Lars Schneider <larsxschneider@gmail.com>
Date
Mar 31, 2017, 16:05 UTC
Message-ID
<4D74C1D4-9EA7-4A17-AFC5-0B54B4A6DD0E@gmail.com>
Hi,

I just got a report with the following output after a "git fetch" operation using Git 2.11.0.windows.3 [1]:

remote: Counting objects: 5922, done. remote: Compressing objects: 100% (14/14), done. error: inflate: data stream error (unknown compression method) error: unable to unpack 6acd8f279a8b20311665f41134579b7380970446 header fatal: SHA1 COLLISION FOUND WITH 6acd8f279a8b20311665f41134579b7380970446 ! fatal: index-pack failed

I would be really surprised if we discovered a SHA1 collision in a production repo. My guess is that this is somehow triggered by a network issue (see data stream error). Any tips how to debug this?

Thanks, Lars

[1] Git for Windows build based on Git v2.11.0
Next: Jeff King
Message 1 of 15 in “SHA1 collision in production repo?! (probably not)”
  1. Lars SchneiderMar 31, 2017
  2. Jeff KingMar 31, 2017
  3. Junio C HamanoMar 31, 2017
  4. Jeff KingMar 31, 2017
  5. Jeff KingMar 31, 2017
  6. Junio C HamanoMar 31, 2017
  7. Jeff KingMar 31, 2017
  8. Junio C HamanoMar 31, 2017
  9. Jeff KingApr 1, 2017
  10. 1/2 sha1_loose_object_info: return error for corrupted objectsJeff King, Apr 1, 2017
  11. Junio C HamanoApr 1, 2017
  12. 2/2 index-pack: detect local corruption in collision checkJeff King, Apr 1, 2017
  13. Junio C HamanoApr 1, 2017
  14. Lars SchneiderSep 12, 2017
  15. Jeff KingSep 12, 2017

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