420 BUG: If the filenode part of an entry in hgtagsfnodes is corrupt and

   421 tags2-visible is missing, `hg tags` aborts.  Corrupting the leading 4 bytes of

   422 node hash (as above) doesn't seem to trigger the issue.  Also note that the

   423 debug command hides the corruption, both with and without tags2-visible.

   424 

   425   $ mv .hg/cache/hgtagsfnodes1 .hg/cache/hgtagsfnodes1.bak

   426   $ hg debugupdatecaches

   427 

   428   >>> import os

   429   >>> with open(".hg/cache/hgtagsfnodes1", "rb+") as fp:

   430   ...     fp.seek(-16, os.SEEK_END) and None

   431   ...     fp.write(b'\xde\xad') and None

   432 

   433   $ f --size --hexdump .hg/cache/hgtagsfnodes1

   434   .hg/cache/hgtagsfnodes1: size=144

   435   0000: bb d1 79 df 00 00 00 00 00 00 00 00 00 00 00 00 |..y.............|

   436   0010: 00 00 00 00 00 00 00 00 78 39 1a 27 0c 04 f2 a8 |........x9.'....|

   437   0020: af 31 de 17 fa b7 42 28 78 ee 5a 2d ad bc 94 3d |.1....B(x.Z-...=|

   438   0030: 7a 94 12 77 0c 04 f2 a8 af 31 de 17 fa b7 42 28 |z..w.....1....B(|

   439   0040: 78 ee 5a 2d ad bc 94 3d 6f a4 50 21 7d 3b 71 8c |x.Z-...=o.P!};q.|

   440   0050: 96 4e f3 7b 89 e5 50 eb da fd 57 89 e7 6c e1 b0 |.N.{..P...W..l..|

   441   0060: 0c 19 2d 7d 0c 04 f2 a8 af 31 de 17 fa b7 42 28 |..-}.....1....B(|

   442   0070: 78 ee 5a 2d ad bc 94 3d 8d bf e6 0e 0c 04 f2 a8 |x.Z-...=........|

   443   0080: de ad de 17 fa b7 42 28 78 ee 5a 2d ad bc 94 3d |......B(x.Z-...=|

   444 

   445   $ hg debugtagscache | tail -2

   446   4 0c192d7d5e6b78a714de54a2e9627952a877e25a 0c04f2a8af31de17fab7422878ee5a2dadbc943d

   447   5 8dbfe60eff306a54259cfe007db9e330e7ecf866 0c04f2a8deadde17fab7422878ee5a2dadbc943d

   448 

   449   $ rm -f .hg/cache/tags2-visible

   450   $ hg debugtagscache | tail -2

   451   4 0c192d7d5e6b78a714de54a2e9627952a877e25a 0c04f2a8af31de17fab7422878ee5a2dadbc943d

   452   5 8dbfe60eff306a54259cfe007db9e330e7ecf866 0c04f2a8deadde17fab7422878ee5a2dadbc943d

   453 

   454   $ hg tags

   455   abort: data/.hgtags.i@0c04f2a8deadde17fab7422878ee5a2dadbc943d: no match found

   456   [50]

   457 

   458 BUG: Unless this file is restored, the `hg tags` in the next unix-permissions

   459 conditional will fail: "abort: data/.hgtags.i@0c04f2a8dead: no match found"

   460 

   461   $ mv .hg/cache/hgtagsfnodes1.bak .hg/cache/hgtagsfnodes1

   462