Mercurial > hg
view tests/test-unamend.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 | 0e2becd1fe0c |
children | 7a90fddb13b0 |
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Test for command `hg unamend` which lives in uncommit extension =============================================================== $ cat >> $HGRCPATH << EOF > [alias] > glog = log -G -T '{rev}:{node|short} {desc}' > [experimental] > evolution = createmarkers, allowunstable > [extensions] > rebase = > amend = > uncommit = > EOF Repo Setup $ hg init repo $ cd repo $ for ch in a b c d e f g h; do touch $ch; echo "foo" >> $ch; hg ci -Aqm "Added "$ch; done $ hg glog @ 7:ec2426147f0e Added h | o 6:87d6d6676308 Added g | o 5:825660c69f0c Added f | o 4:aa98ab95a928 Added e | o 3:62615734edd5 Added d | o 2:28ad74487de9 Added c | o 1:29becc82797a Added b | o 0:18d04c59bb5d Added a Trying to unamend when there was no amend done $ hg unamend abort: changeset must have one predecessor, found 0 predecessors [10] Unamend on clean wdir and tip $ echo "bar" >> h $ hg amend $ hg exp # HG changeset patch # User test # Date 0 0 # Thu Jan 01 00:00:00 1970 +0000 # Node ID c9fa1a715c1b7661c0fafb362a9f30bd75878d7d # Parent 87d6d66763085b629e6d7ed56778c79827273022 Added h diff -r 87d6d6676308 -r c9fa1a715c1b h --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/h Thu Jan 01 00:00:00 1970 +0000 @@ -0,0 +1,2 @@ +foo +bar $ hg glog --hidden @ 8:c9fa1a715c1b Added h | | x 7:ec2426147f0e Added h |/ o 6:87d6d6676308 Added g | o 5:825660c69f0c Added f | o 4:aa98ab95a928 Added e | o 3:62615734edd5 Added d | o 2:28ad74487de9 Added c | o 1:29becc82797a Added b | o 0:18d04c59bb5d Added a $ hg unamend $ hg glog --hidden @ 9:46d02d47eec6 Added h | | x 8:c9fa1a715c1b Added h |/ | x 7:ec2426147f0e Added h |/ o 6:87d6d6676308 Added g | o 5:825660c69f0c Added f | o 4:aa98ab95a928 Added e | o 3:62615734edd5 Added d | o 2:28ad74487de9 Added c | o 1:29becc82797a Added b | o 0:18d04c59bb5d Added a $ hg diff diff -r 46d02d47eec6 h --- a/h Thu Jan 01 00:00:00 1970 +0000 +++ b/h Thu Jan 01 00:00:00 1970 +0000 @@ -1,1 +1,2 @@ foo +bar $ hg exp # HG changeset patch # User test # Date 0 0 # Thu Jan 01 00:00:00 1970 +0000 # Node ID 46d02d47eec6ca096b8dcab3f8f5579c40c3dd9a # Parent 87d6d66763085b629e6d7ed56778c79827273022 Added h diff -r 87d6d6676308 -r 46d02d47eec6 h --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/h Thu Jan 01 00:00:00 1970 +0000 @@ -0,0 +1,1 @@ +foo $ hg status M h $ hg log -r . -T '{extras % "{extra}\n"}' --config alias.log=log branch=default unamend_source=c9fa1a715c1b7661c0fafb362a9f30bd75878d7d Using unamend to undo an unamed (intentional) $ hg unamend $ hg exp # HG changeset patch # User test # Date 0 0 # Thu Jan 01 00:00:00 1970 +0000 # Node ID 850ddfc1bc662997ec6094ada958f01f0cc8070a # Parent 87d6d66763085b629e6d7ed56778c79827273022 Added h diff -r 87d6d6676308 -r 850ddfc1bc66 h --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/h Thu Jan 01 00:00:00 1970 +0000 @@ -0,0 +1,2 @@ +foo +bar $ hg diff Unamend on a dirty working directory $ echo "bar" >> a $ hg amend $ echo "foobar" >> a $ echo "bar" >> b $ hg status M a M b $ hg unamend $ hg status M a M b $ hg diff diff -r ec338db45d51 a --- a/a Thu Jan 01 00:00:00 1970 +0000 +++ b/a Thu Jan 01 00:00:00 1970 +0000 @@ -1,1 +1,3 @@ foo +bar +foobar diff -r ec338db45d51 b --- a/b Thu Jan 01 00:00:00 1970 +0000 +++ b/b Thu Jan 01 00:00:00 1970 +0000 @@ -1,1 +1,2 @@ foo +bar Unamending an added file $ hg ci -m "Added things to a and b" $ echo foo > bar $ hg add bar $ hg amend $ hg unamend $ hg status A bar $ hg revert --all forgetting bar Unamending a removed file $ hg remove a $ hg amend $ hg unamend $ hg status R a ? bar $ hg revert --all undeleting a Unamending an added file with dirty wdir status $ hg add bar $ hg amend $ echo bar >> bar $ hg status M bar $ hg unamend $ hg status A bar $ hg diff diff -r 7f79409af972 bar --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/bar Thu Jan 01 00:00:00 1970 +0000 @@ -0,0 +1,2 @@ +foo +bar $ hg revert --all forgetting bar $ rm bar Unamending in middle of a stack $ hg glog @ 19:7f79409af972 Added things to a and b | o 12:ec338db45d51 Added h | o 6:87d6d6676308 Added g | o 5:825660c69f0c Added f | o 4:aa98ab95a928 Added e | o 3:62615734edd5 Added d | o 2:28ad74487de9 Added c | o 1:29becc82797a Added b | o 0:18d04c59bb5d Added a $ hg up 5 2 files updated, 0 files merged, 2 files removed, 0 files unresolved $ echo bar >> f $ hg amend 3 new orphan changesets $ hg rebase -s 6 -d . -q $ hg glog o 23:03ddd6fc5af1 Added things to a and b | o 22:3e7b64ee157b Added h | o 21:49635b68477e Added g | @ 20:93f0e8ffab32 Added f | o 4:aa98ab95a928 Added e | o 3:62615734edd5 Added d | o 2:28ad74487de9 Added c | o 1:29becc82797a Added b | o 0:18d04c59bb5d Added a $ hg --config experimental.evolution=createmarkers unamend abort: cannot unamend changeset with children [10] $ hg unamend 3 new orphan changesets Trying to unamend a public changeset $ hg up -C 23 5 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg phase -r . -p 1 new phase-divergent changesets $ hg unamend abort: cannot unamend public changesets (see 'hg help phases' for details) [10] Testing whether unamend retains copies or not $ hg status $ hg mv a foo $ hg ci -m "Moved a to foo" $ hg exp --git # HG changeset patch # User test # Date 0 0 # Thu Jan 01 00:00:00 1970 +0000 # Node ID cfef290346fbee5126313d7e1aab51d877679b09 # Parent 03ddd6fc5af19e028c44a2fd6d790dd22712f231 Moved a to foo diff --git a/a b/foo rename from a rename to foo $ hg mv b foobar $ hg diff --git diff --git a/b b/foobar rename from b rename to foobar $ hg amend $ hg exp --git # HG changeset patch # User test # Date 0 0 # Thu Jan 01 00:00:00 1970 +0000 # Node ID eca050985275bb271ce3092b54e56ea5c85d29a3 # Parent 03ddd6fc5af19e028c44a2fd6d790dd22712f231 Moved a to foo diff --git a/a b/foo rename from a rename to foo diff --git a/b b/foobar rename from b rename to foobar $ hg mv c wat $ hg unamend $ hg verify -v repository uses revlog format 1 checking changesets checking manifests crosschecking files in changesets and manifests checking files checked 28 changesets with 16 changes to 11 files Retained copies in new prdecessor commit $ hg exp --git # HG changeset patch # User test # Date 0 0 # Thu Jan 01 00:00:00 1970 +0000 # Node ID 552e3af4f01f620f88ca27be1f898316235b736a # Parent 03ddd6fc5af19e028c44a2fd6d790dd22712f231 Moved a to foo diff --git a/a b/foo rename from a rename to foo Retained copies in working directoy $ hg diff --git diff --git a/b b/foobar rename from b rename to foobar diff --git a/c b/wat rename from c rename to wat $ hg revert -qa $ rm foobar wat Rename a->b, then amend b->c. After unamend, should look like b->c. $ hg co -q 0 $ hg mv a b $ hg ci -qm 'move to a b' $ hg mv b c $ hg amend $ hg unamend $ hg st --copies --change . A b a R a $ hg st --copies A c b R b $ hg revert -qa $ rm c Rename a->b, then amend b->c, and working copy change c->d. After unamend, should look like b->d $ hg co -q 0 $ hg mv a b $ hg ci -qm 'move to a b' warning: commit already existed in the repository! $ hg mv b c $ hg amend warning: commit already existed in the repository! $ hg mv c d $ hg unamend $ hg st --copies --change . A b a R a $ hg st --copies A d b R b