view tests/test-mq-qdelete.t @ 46607:e9901d01d135

revlog: add a mechanism to verify expected file position before appending

If someone uses `hg debuglocks`, or some non-hg process writes to the .hg
directory without respecting the locks, or if the repo's on a networked
filesystem, it's possible for the revlog code to write out corrupted data.

The form of this corruption can vary depending on what data was written and how
that happened. We are in the "networked filesystem" case (though I've had users
also do this to themselves with the "`hg debuglocks`" scenario), and most often
see this with the changelog. What ends up happening is we produce two items
(let's call them rev1 and rev2) in the .i file that have the same linkrev,
baserev, and offset into the .d file, while the data in the .d file is appended
properly. rev2's compressed_size is accurate for rev2, but when we go to
decompress the data in the .d file, we use the offset that's recorded in the
index file, which is the same as rev1, and attempt to decompress
rev2.compressed_size bytes of rev1's data. This usually does not succeed. :)

When using inline data, this also fails, though I haven't investigated why too
closely. This shows up as a "patch decode" error. I believe what's happening
there is that we're basically ignoring the offset field, getting the data
properly, but since baserev != rev, it thinks this is a delta based on rev
(instead of a full text) and can't actually apply it as such.

For now, I'm going to make this an optional component and default it to entirely
off. I may increase the default severity of this in the future, once I've
enabled it for my users and we gain more experience with it. Luckily, most of my
users have a versioned filesystem and can roll back to before the corruption has
been written, it's just a hassle to do so and not everyone knows how (so it's a
support burden). Users on other filesystems will not have that luxury, and this
can cause them to have a corrupted repository that they are unlikely to know how
to resolve, and they'll see this as a data-loss event. Refusing to create the
corruption is a much better user experience.

This mechanism is not perfect. There may be false-negatives (racy writes that
are not detected). There should not be any false-positives (non-racy writes that
are detected as such). This is not a mechanism that makes putting a repo on a
networked filesystem "safe" or "supported", just *less* likely to cause
corruption.

Differential Revision: https://phab.mercurial-scm.org/D9952

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "mq=" >> $HGRCPATH

  $ hg init a
  $ cd a

  $ echo 'base' > base
  $ hg ci -Ambase -d '1 0'
  adding base

  $ hg qnew -d '1 0' pa
  $ hg qnew -d '1 0' pb
  $ hg qnew -d '1 0' pc

  $ hg qdel
  abort: qdelete requires at least one revision or patch name
  [255]

  $ hg qdel pc
  abort: cannot delete applied patch pc
  [255]

  $ hg qpop
  popping pc
  now at: pb

Delete the same patch twice in one command (issue2427)

  $ hg qdel pc pc

  $ hg qseries
  pa
  pb

  $ ls .hg/patches
  pa
  pb
  series
  status

  $ hg qpop
  popping pb
  now at: pa

  $ hg qdel -k 1

  $ ls .hg/patches
  pa
  pb
  series
  status

  $ hg qdel -r pa
  patch pa finalized without changeset message

  $ hg qapplied

  $ hg log --template '{rev} {desc}\n'
  1 [mq]: pa
  0 base

  $ hg qnew pd
  $ hg qnew pe
  $ hg qnew pf

  $ hg qdel -r pe
  abort: cannot delete revision 3 above applied patches
  [255]

  $ hg qdel -r qbase:pe
  patch pd finalized without changeset message
  patch pe finalized without changeset message

  $ hg qapplied
  pf

  $ hg log --template '{rev} {desc}\n'
  4 [mq]: pf
  3 [mq]: pe
  2 [mq]: pd
  1 [mq]: pa
  0 base

  $ cd ..

  $ hg init b
  $ cd b

  $ echo 'base' > base
  $ hg ci -Ambase -d '1 0'
  adding base

  $ hg qfinish
  abort: no revisions specified
  [255]

  $ hg qfinish -a
  no patches applied

  $ hg qnew -d '1 0' pa
  $ hg qnew -d '1 0' pb
  $ hg qnew pc # XXX fails to apply by /usr/bin/patch if we put a date

  $ hg qfinish 0
  abort: revision 0 is not managed
  [255]

  $ hg qfinish pb
  abort: cannot delete revision 2 above applied patches
  [255]

  $ hg qpop
  popping pc
  now at: pb

  $ hg qfinish -a pc
  abort: unknown revision 'pc'
  [255]

  $ hg qpush
  applying pc
  patch pc is empty
  now at: pc

  $ hg qfinish qbase:pb
  patch pa finalized without changeset message
  patch pb finalized without changeset message

  $ hg qapplied
  pc

  $ hg log --template '{rev} {desc}\n'
  3 imported patch pc
  2 [mq]: pb
  1 [mq]: pa
  0 base

  $ hg qfinish -a pc
  patch pc finalized without changeset message

  $ hg qapplied

  $ hg log --template '{rev} {desc}\n'
  3 imported patch pc
  2 [mq]: pb
  1 [mq]: pa
  0 base

  $ ls .hg/patches
  series
  status

qdel -k X && hg qimp -e X used to trigger spurious output with versioned queues

  $ hg init --mq
  $ hg qimport -r 3
  $ hg qpop
  popping imported_patch_pc
  patch queue now empty
  $ hg qdel -k imported_patch_pc
  $ hg qimp -e imported_patch_pc
  adding imported_patch_pc to series file
  $ hg qfinish -a
  no patches applied


resilience to inconsistency: qfinish -a with applied patches not in series

  $ hg qser
  imported_patch_pc
  $ hg qapplied
  $ hg qpush
  applying imported_patch_pc
  patch imported_patch_pc is empty
  now at: imported_patch_pc
  $ echo next >>  base
  $ hg qrefresh -d '1 0'
  $ echo > .hg/patches/series # remove 3.diff from series to confuse mq
  $ hg qfinish -a
  revision 47dfa8501675 refers to unknown patches: imported_patch_pc

more complex state 'both known and unknown patches

  $ echo hip >>  base
  $ hg qnew -f -d '1 0' -m 4 4.diff
  $ echo hop >>  base
  $ hg qnew -f -d '1 0' -m 5 5.diff
  $ echo > .hg/patches/series # remove 4.diff and 5.diff from series to confuse mq
  $ echo hup >>  base
  $ hg qnew -f -d '1 0' -m 6 6.diff
  $ echo pup > base
  $ hg qfinish -a
  warning: uncommitted changes in the working directory
  revision 2b1c98802260 refers to unknown patches: 5.diff
  revision 33a6861311c0 refers to unknown patches: 4.diff

  $ cd ..