Mercurial > hg
view tests/test-pull-r.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 | 95c4cca641f6 |
children | 8c4881c07f57 |
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$ cat <<EOF >> $HGRCPATH > [ui] > interactive = true > EOF $ hg init repo $ cd repo $ echo foo > foo $ hg ci -qAm 'add foo' $ echo >> foo $ hg ci -m 'change foo' $ hg up -qC 0 $ echo bar > bar $ hg ci -qAm 'add bar' $ hg log changeset: 2:effea6de0384 tag: tip parent: 0:bbd179dfa0a7 user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: add bar changeset: 1:ed1b79f46b9a user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: change foo changeset: 0:bbd179dfa0a7 user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: add foo $ cd .. don't show "(+1 heads)" message when pulling closed head $ hg clone -q repo repo2 $ hg clone -q repo2 repo3 $ cd repo2 $ hg up -q 0 $ echo hello >> foo $ hg ci -mx1 created new head $ hg ci -mx2 --close-branch $ cd ../repo3 $ hg heads -q --closed 2:effea6de0384 1:ed1b79f46b9a $ hg pull --confirm << EOF > n > EOF pulling from $TESTTMP/repo2 searching for changes adding changesets adding manifests adding file changes adding 2 changesets with 1 changes to 1 files new changesets 8c900227dd5d:00cfe9073916 accept incoming changes (yn)? n transaction abort! rollback completed abort: user aborted [255] $ hg pull --config pull.confirm=true << EOF > n > EOF pulling from $TESTTMP/repo2 searching for changes adding changesets adding manifests adding file changes adding 2 changesets with 1 changes to 1 files new changesets 8c900227dd5d:00cfe9073916 accept incoming changes (yn)? n transaction abort! rollback completed abort: user aborted [255] $ hg pull --confirm << EOF > y > EOF pulling from $TESTTMP/repo2 searching for changes adding changesets adding manifests adding file changes adding 2 changesets with 1 changes to 1 files new changesets 8c900227dd5d:00cfe9073916 accept incoming changes (yn)? y added 2 changesets with 1 changes to 1 files new changesets 8c900227dd5d:00cfe9073916 (run 'hg update' to get a working copy) $ hg heads -q --closed 4:00cfe9073916 2:effea6de0384 1:ed1b79f46b9a pull--confirm config option should be ignored if HGPLAIN is set $ HGPLAIN=1 hg pull --config pull.confirm=True pulling from $TESTTMP/repo2 searching for changes no changes found $ cd .. $ hg init copy $ cd copy Pull a missing revision: $ hg pull -qr missing ../repo abort: unknown revision 'missing' [255] Pull multiple revisions with update: $ hg pull -qu -r 0 -r 1 ../repo $ hg -q parents 0:bbd179dfa0a7 $ hg rollback repository tip rolled back to revision -1 (undo pull) working directory now based on revision -1 $ hg pull -qr 0 ../repo $ hg log changeset: 0:bbd179dfa0a7 tag: tip user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: add foo $ hg pull -qr 1 ../repo $ hg log changeset: 1:ed1b79f46b9a tag: tip user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: change foo changeset: 0:bbd179dfa0a7 user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: add foo This used to abort: received changelog group is empty: $ hg pull -qr 1 ../repo Test race condition with -r and -U (issue4707) We pull '-U -r <name>' and the name change right after/during the changegroup emission. We use http because http is better is our racy-est option. $ echo babar > ../repo/jungle $ cat <<EOF > ../repo/.hg/hgrc > [hooks] > outgoing.makecommit = hg ci -Am 'racy commit'; echo committed in pull-race > EOF $ hg serve -R ../repo -p $HGPORT2 -d --pid-file=../repo.pid $ cat ../repo.pid >> $DAEMON_PIDS $ hg pull --rev default --update http://localhost:$HGPORT2/ pulling from http://localhost:$HGPORT2/ searching for changes adding changesets adding manifests adding file changes added 1 changesets with 1 changes to 1 files (+1 heads) new changesets effea6de0384 2 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg log -G @ changeset: 2:effea6de0384 | tag: tip | parent: 0:bbd179dfa0a7 | user: test | date: Thu Jan 01 00:00:00 1970 +0000 | summary: add bar | | o changeset: 1:ed1b79f46b9a |/ user: test | date: Thu Jan 01 00:00:00 1970 +0000 | summary: change foo | o changeset: 0:bbd179dfa0a7 user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: add foo $ cd .. $ killdaemons.py