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Bug: git branch --unset-upstream command can nuke config when disk is full.

From
Ddemerphq <demerphq@gmail.com>
Date
Sep 13, 2017, 11:59 UTC
Message-ID
<CANgJU+Wj_sN8Px6rweHMw_iAX8UA3mW9x4NVCctpUCs8_3ytLw@mail.gmail.com>
After being away for a while I saw the following message in one of my git repos:
$ git status
On branch yves/xxx
Your branch is based on 'origin/yves/xxx', but the upstream is gone.
  (use "git branch --unset-upstream" to fixup)

nothing to commit, working tree clean $ git branch --unset-upstream fatal: could not unset 'branch.yves/simple_projection.merge'

At this point my .git/config file was empty, and all of my config was lost.

I assume that things that rewrite .git/config do not check for a successful write before deleting the old version of the file.

This was git version 2.14.1
Yves
-- 
perl -Mre=debug -e "/just|another|perl|hacker/"
Next: Jeff King
Message 1 of 46 in “Bug: git branch --unset-upstream command can nuke config when disk is full.”
  1. demerphqSep 13, 2017
  2. Jeff KingSep 13, 2017
  3. demerphqSep 13, 2017
  4. Jeff KingSep 13, 2017
  5. demerphqSep 13, 2017
  6. Jeff KingSep 13, 2017
  7. demerphqSep 13, 2017
  8. Jeff KingSep 13, 2017
  9. demerphqSep 13, 2017
  10. 0/7 config.c may fail to notice some write() failuresJeff King, Sep 13, 2017
  11. 1/7 config: avoid "write_in_full(fd, buf, len) < len" patternJeff King, Sep 13, 2017
  12. Jonathan NiederSep 13, 2017
  13. Jeff KingSep 13, 2017
  14. Jonathan NiederSep 13, 2017
  15. Jeff KingSep 13, 2017
  16. config: avoid "write_in_full(fd, buf, len) < len" patternJeff King, Sep 13, 2017
  17. Jonathan NiederSep 13, 2017
  18. Jeff KingSep 13, 2017
  19. Jonathan NiederSep 13, 2017
  20. Jonathan NiederSep 13, 2017
  21. Ramsay JonesSep 13, 2017
  22. Ramsay JonesSep 13, 2017
  23. Jeff KingSep 15, 2017
  24. Ramsay JonesSep 15, 2017
  25. Junio C HamanoSep 13, 2017
  26. 2/7 get-tar-commit-id: check write_in_full() return against 0Jeff King, Sep 13, 2017
  27. Jonathan NiederSep 13, 2017
  28. Jeff KingSep 13, 2017
  29. Jeff KingSep 13, 2017
  30. Jonathan NiederSep 13, 2017
  31. Jeff KingSep 15, 2017
  32. 3/7 avoid "write_in_full(fd, buf, len) != len" patternJeff King, Sep 13, 2017
  33. Jonathan NiederSep 13, 2017
  34. Jeff KingSep 15, 2017
  35. 4/7 convert less-trivial versions of "write_in_full() != len"Jeff King, Sep 13, 2017
  36. Jonathan NiederSep 13, 2017
  37. 5/7 pkt-line: check write_in_full() errors against "< 0"Jeff King, Sep 13, 2017
  38. Jonathan NiederSep 13, 2017
  39. 6/7 notes-merge: use ssize_t for write_in_full() return valueJeff King, Sep 13, 2017
  40. Jonathan NiederSep 13, 2017
  41. Jeff KingSep 15, 2017
  42. 7/7 config: flip return value of store_write_*()Jeff King, Sep 13, 2017
  43. Jonathan NiederSep 13, 2017
  44. Jeff KingSep 15, 2017
  45. 8/7 read_pack_header: handle signed/unsigned comparison in read resultJeff King, Sep 13, 2017
  46. Jonathan NiederSep 13, 2017

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