Mercurial > hg
view tests/test-sparse-profiles.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 | 21733e8c924f |
children | 38941a28406a |
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test sparse $ hg init myrepo $ cd myrepo $ cat > .hg/hgrc <<EOF > [extensions] > sparse= > purge= > strip= > rebase= > EOF Config file without [section] is rejected $ cat > bad.sparse <<EOF > *.html > EOF $ hg debugsparse --import-rules bad.sparse abort: sparse config entry outside of section: *.html (add an [include] or [exclude] line to declare the entry type) [255] $ rm bad.sparse $ echo a > index.html $ echo x > data.py $ echo z > readme.txt $ cat > webpage.sparse <<EOF > # frontend sparse profile > [include] > *.html > EOF $ cat > backend.sparse <<EOF > # backend sparse profile > [include] > *.py > EOF $ hg ci -Aqm 'initial' $ hg debugsparse --include '*.sparse' Verify enabling a single profile works $ hg debugsparse --enable-profile webpage.sparse $ ls -A .hg backend.sparse index.html webpage.sparse Verify enabling two profiles works $ hg debugsparse --enable-profile backend.sparse $ ls -A .hg backend.sparse data.py index.html webpage.sparse Verify disabling a profile works $ hg debugsparse --disable-profile webpage.sparse $ ls -A .hg backend.sparse data.py webpage.sparse Verify that a profile is updated across multiple commits $ cat > webpage.sparse <<EOF > # frontend sparse profile > [include] > *.html > EOF $ cat > backend.sparse <<EOF > # backend sparse profile > [include] > *.py > *.txt > EOF $ echo foo >> data.py $ hg ci -m 'edit profile' $ ls -A .hg backend.sparse data.py readme.txt webpage.sparse $ hg up -q 0 $ ls -A .hg backend.sparse data.py webpage.sparse $ hg up -q 1 $ ls -A .hg backend.sparse data.py readme.txt webpage.sparse Introduce a conflicting .hgsparse change $ hg up -q 0 $ cat > backend.sparse <<EOF > # Different backend sparse profile > [include] > *.html > EOF $ echo bar >> data.py $ hg ci -qAm "edit profile other" $ ls -A .hg backend.sparse index.html webpage.sparse Verify conflicting merge pulls in the conflicting changes $ hg merge 1 temporarily included 2 file(s) in the sparse checkout for merging merging backend.sparse merging data.py warning: conflicts while merging backend.sparse! (edit, then use 'hg resolve --mark') warning: conflicts while merging data.py! (edit, then use 'hg resolve --mark') 0 files updated, 0 files merged, 0 files removed, 2 files unresolved use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon [1] $ rm *.orig $ ls -A .hg backend.sparse data.py index.html webpage.sparse Verify resolving the merge removes the temporarily unioned files $ cat > backend.sparse <<EOF > # backend sparse profile > [include] > *.html > *.txt > EOF $ hg resolve -m backend.sparse $ cat > data.py <<EOF > x > foo > bar > EOF $ hg resolve -m data.py (no more unresolved files) $ hg ci -qAm "merge profiles" $ ls -A .hg backend.sparse index.html readme.txt webpage.sparse $ hg cat -r . data.py x foo bar Verify stripping refreshes dirstate $ hg strip -q -r . $ ls -A .hg backend.sparse index.html webpage.sparse Verify rebase conflicts pulls in the conflicting changes $ hg up -q 1 $ ls -A .hg backend.sparse data.py readme.txt webpage.sparse $ hg rebase -d 2 rebasing 1:a2b1de640a62 "edit profile" temporarily included 2 file(s) in the sparse checkout for merging merging backend.sparse merging data.py warning: conflicts while merging backend.sparse! (edit, then use 'hg resolve --mark') warning: conflicts while merging data.py! (edit, then use 'hg resolve --mark') unresolved conflicts (see 'hg resolve', then 'hg rebase --continue') [240] $ rm *.orig $ ls -A .hg backend.sparse data.py index.html webpage.sparse Verify resolving conflict removes the temporary files $ cat > backend.sparse <<EOF > [include] > *.html > *.txt > EOF $ hg resolve -m backend.sparse $ cat > data.py <<EOF > x > foo > bar > EOF $ hg resolve -m data.py (no more unresolved files) continue: hg rebase --continue $ hg rebase -q --continue $ ls -A .hg backend.sparse index.html readme.txt webpage.sparse $ hg cat -r . data.py x foo bar Test checking out a commit that does not contain the sparse profile. The warning message can be suppressed by setting missingwarning = false in [sparse] section of your config: $ hg debugsparse --reset $ hg rm *.sparse $ hg commit -m "delete profiles" $ hg up -q ".^" $ hg debugsparse --enable-profile backend.sparse $ ls -A .hg index.html readme.txt $ hg up tip | grep warning warning: sparse profile 'backend.sparse' not found in rev bfcb76de99cc - ignoring it [1] $ ls -A .hg data.py index.html readme.txt $ hg debugsparse --disable-profile backend.sparse | grep warning warning: sparse profile 'backend.sparse' not found in rev bfcb76de99cc - ignoring it [1] $ cat >> .hg/hgrc <<EOF > [sparse] > missingwarning = false > EOF $ hg debugsparse --enable-profile backend.sparse $ cd .. #if unix-permissions Test file permissions changing across a sparse profile change $ hg init sparseperm $ cd sparseperm $ cat > .hg/hgrc <<EOF > [extensions] > sparse= > EOF $ touch a b $ cat > .hgsparse <<EOF > [include] > a > EOF $ hg commit -Aqm 'initial' $ chmod a+x b $ hg commit -qm 'make executable' $ cat >> .hgsparse <<EOF > b > EOF $ hg commit -qm 'update profile' $ hg up -q 0 $ hg debugsparse --enable-profile .hgsparse $ hg up -q 2 $ ls -l b -rwxr-xr-x* b (glob) #endif