Mercurial > hg
view tests/test-status-rev.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
author | Kyle Lippincott <spectral@google.com> |
---|---|
date | Wed, 03 Feb 2021 16:33:10 -0800 |
parents | 5abc47d4ca6b |
children | 55c6ebd11cb9 |
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Tests of 'hg status --rev <rev>' to make sure status between <rev> and '.' get combined correctly with the dirstate status. $ hg init First commit $ "$PYTHON" $TESTDIR/generate-working-copy-states.py state 2 1 $ hg addremove --similarity 0 adding content1_content1_content1-tracked adding content1_content1_content1-untracked adding content1_content1_content3-tracked adding content1_content1_content3-untracked adding content1_content1_missing-tracked adding content1_content1_missing-untracked adding content1_content2_content1-tracked adding content1_content2_content1-untracked adding content1_content2_content2-tracked adding content1_content2_content2-untracked adding content1_content2_content3-tracked adding content1_content2_content3-untracked adding content1_content2_missing-tracked adding content1_content2_missing-untracked adding content1_missing_content1-tracked adding content1_missing_content1-untracked adding content1_missing_content3-tracked adding content1_missing_content3-untracked adding content1_missing_missing-tracked adding content1_missing_missing-untracked $ hg commit -m first Second commit $ "$PYTHON" $TESTDIR/generate-working-copy-states.py state 2 2 $ hg addremove --similarity 0 removing content1_missing_content1-tracked removing content1_missing_content1-untracked removing content1_missing_content3-tracked removing content1_missing_content3-untracked removing content1_missing_missing-tracked removing content1_missing_missing-untracked adding missing_content2_content2-tracked adding missing_content2_content2-untracked adding missing_content2_content3-tracked adding missing_content2_content3-untracked adding missing_content2_missing-tracked adding missing_content2_missing-untracked $ hg commit -m second Working copy $ "$PYTHON" $TESTDIR/generate-working-copy-states.py state 2 wc $ hg addremove --similarity 0 adding content1_missing_content1-tracked adding content1_missing_content1-untracked adding content1_missing_content3-tracked adding content1_missing_content3-untracked adding content1_missing_missing-tracked adding content1_missing_missing-untracked adding missing_missing_content3-tracked adding missing_missing_content3-untracked adding missing_missing_missing-tracked adding missing_missing_missing-untracked $ hg forget *_*_*-untracked $ rm *_*_missing-* Status compared to parent of the working copy, i.e. the dirstate status $ hg status -A --rev 1 'glob:missing_content2_content3-tracked' M missing_content2_content3-tracked $ hg status -A --rev 1 'glob:missing_content2_content2-tracked' C missing_content2_content2-tracked $ hg status -A --rev 1 'glob:missing_missing_content3-tracked' A missing_missing_content3-tracked $ hg status -A --rev 1 'glob:missing_missing_content3-untracked' ? missing_missing_content3-untracked $ hg status -A --rev 1 'glob:missing_content2_*-untracked' R missing_content2_content2-untracked R missing_content2_content3-untracked R missing_content2_missing-untracked $ hg status -A --rev 1 'glob:missing_*_missing-tracked' ! missing_content2_missing-tracked ! missing_missing_missing-tracked $ hg status -A --rev 1 'glob:missing_missing_missing-untracked' missing_missing_missing-untracked: $ENOENT$ Status between first and second commit. Should ignore dirstate status. $ hg status -A --rev 0:1 'glob:content1_content2_*' M content1_content2_content1-tracked M content1_content2_content1-untracked M content1_content2_content2-tracked M content1_content2_content2-untracked M content1_content2_content3-tracked M content1_content2_content3-untracked M content1_content2_missing-tracked M content1_content2_missing-untracked $ hg status -A --rev 0:1 'glob:content1_content1_*' C content1_content1_content1-tracked C content1_content1_content1-untracked C content1_content1_content3-tracked C content1_content1_content3-untracked C content1_content1_missing-tracked C content1_content1_missing-untracked $ hg status -A --rev 0:1 'glob:missing_content2_*' A missing_content2_content2-tracked A missing_content2_content2-untracked A missing_content2_content3-tracked A missing_content2_content3-untracked A missing_content2_missing-tracked A missing_content2_missing-untracked $ hg status -A --rev 0:1 'glob:content1_missing_*' R content1_missing_content1-tracked R content1_missing_content1-untracked R content1_missing_content3-tracked R content1_missing_content3-untracked R content1_missing_missing-tracked R content1_missing_missing-untracked $ hg status -A --rev 0:1 'glob:missing_missing_*' Status compared to one revision back, checking that the dirstate status is correctly combined with the inter-revision status $ hg status -A --rev 0 'glob:content1_*_content[23]-tracked' M content1_content1_content3-tracked M content1_content2_content2-tracked M content1_content2_content3-tracked M content1_missing_content3-tracked $ hg status -A --rev 0 'glob:content1_*_content1-tracked' C content1_content1_content1-tracked C content1_content2_content1-tracked C content1_missing_content1-tracked $ hg status -A --rev 0 'glob:missing_*_content?-tracked' A missing_content2_content2-tracked A missing_content2_content3-tracked A missing_missing_content3-tracked BROKEN: missing_content2_content[23]-untracked exist, so should be listed $ hg status -A --rev 0 'glob:missing_*_content?-untracked' ? missing_missing_content3-untracked $ hg status -A --rev 0 'glob:content1_*_*-untracked' R content1_content1_content1-untracked R content1_content1_content3-untracked R content1_content1_missing-untracked R content1_content2_content1-untracked R content1_content2_content2-untracked R content1_content2_content3-untracked R content1_content2_missing-untracked R content1_missing_content1-untracked R content1_missing_content3-untracked R content1_missing_missing-untracked $ hg status -A --rev 0 'glob:*_*_missing-tracked' ! content1_content1_missing-tracked ! content1_content2_missing-tracked ! content1_missing_missing-tracked ! missing_content2_missing-tracked ! missing_missing_missing-tracked $ hg status -A --rev 0 'glob:missing_*_missing-untracked'