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view tests/test-rebase-rename.t @ 49000:dd6b67d5c256 stable
rust: fix unsound `OwningDirstateMap`
As per the previous patch, `OwningDirstateMap` is unsound. Self-referential
structs are difficult to implement correctly in Rust since the compiler is
free to move structs around as much as it wants to. They are also very rarely
needed in practice, so the state-of-the-art on how they should be done within
the Rust rules is still a bit new.
The crate `ouroboros` is an attempt at providing a safe way (in the Rust sense)
of declaring self-referential structs. It is getting a lot attention and was
improved very quickly when soundness issues were found in the past: rather than
relying on our own (limited) review circle, we might as well use the de-facto
common crate to fix this problem. This will give us a much better chance of
finding issues should any new ones be discovered as well as the benefit of
fewer `unsafe` APIs of our own.
I was starting to think about how I would present a safe API to the old struct
but soon realized that the callback-based approach was already done in
`ouroboros`, along with a lot more care towards refusing incorrect structs.
In short: we don't return a mutable reference to the `DirstateMap` anymore, we
expect users of its API to pass a `FnOnce` that takes the map as an argument.
This allows our `OwningDirstateMap` to control the input and output lifetimes
of the code that modifies it to prevent such issues.
Changing to `ouroboros` meant changing every API with it, but it is relatively
low churn in the end. It correctly identified the example buggy modification of
`copy_map_insert` outlined in the previous patch as violating the borrow rules.
Differential Revision: https://phab.mercurial-scm.org/D12429
author | Raphaël Gomès <rgomes@octobus.net> |
---|---|
date | Tue, 05 Apr 2022 10:55:28 +0200 |
parents | 1703a7f9d5b8 |
children |
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$ cat >> $HGRCPATH <<EOF > [extensions] > rebase= > > [alias] > tlog = log --template "{rev}: {node|short} '{desc}' {branches}\n" > tglog = tlog --graph > EOF $ hg init a $ cd a $ mkdir d $ echo a > a $ hg ci -Am A adding a $ echo b > d/b $ hg ci -Am B adding d/b $ hg mv d d-renamed moving d/b to d-renamed/b $ hg ci -m 'rename B' $ hg up -q -C 1 $ hg mv a a-renamed $ echo x > d/x $ hg add d/x $ hg ci -m 'rename A' created new head $ hg tglog @ 3: 73a3ee40125d 'rename A' | | o 2: 220d0626d185 'rename B' |/ o 1: 3ab5da9a5c01 'B' | o 0: 1994f17a630e 'A' Rename is tracked: $ hg tlog -p --git -r tip 3: 73a3ee40125d 'rename A' diff --git a/a b/a-renamed rename from a rename to a-renamed diff --git a/d/x b/d/x new file mode 100644 --- /dev/null +++ b/d/x @@ -0,0 +1,1 @@ +x Rebase the revision containing the rename: $ hg rebase -s 3 -d 2 rebasing 3:73a3ee40125d tip "rename A" saved backup bundle to $TESTTMP/a/.hg/strip-backup/73a3ee40125d-1d78ebcf-rebase.hg $ hg tglog @ 3: 032a9b75e83b 'rename A' | o 2: 220d0626d185 'rename B' | o 1: 3ab5da9a5c01 'B' | o 0: 1994f17a630e 'A' Rename is not lost: $ hg tlog -p --git -r tip 3: 032a9b75e83b 'rename A' diff --git a/a b/a-renamed rename from a rename to a-renamed diff --git a/d-renamed/x b/d-renamed/x new file mode 100644 --- /dev/null +++ b/d-renamed/x @@ -0,0 +1,1 @@ +x Rebased revision does not contain information about b (issue3739) $ hg log -r 3 --debug changeset: 3:032a9b75e83bff1dcfb6cbfa4ef50a704bf1b569 tag: tip phase: draft parent: 2:220d0626d185f372d9d8f69d9c73b0811d7725f7 parent: -1:0000000000000000000000000000000000000000 manifest: 3:035d66b27a1b06b2d12b46d41a39adb7a200c370 user: test date: Thu Jan 01 00:00:00 1970 +0000 files+: a-renamed d-renamed/x files-: a extra: branch=default extra: rebase_source=73a3ee40125d6f0f347082e5831ceccb3f005f8a description: rename A $ repeatchange() { > hg checkout $1 > hg cp a z > echo blah >> z > hg commit -Am "$2" --user "$3" > } $ repeatchange 1 "E" "user1" 2 files updated, 0 files merged, 3 files removed, 0 files unresolved created new head $ repeatchange 1 "E" "user2" 0 files updated, 0 files merged, 1 files removed, 0 files unresolved created new head $ hg tglog @ 5: af8ad1f97097 'E' | | o 4: 60f545c27784 'E' |/ | o 3: 032a9b75e83b 'rename A' | | | o 2: 220d0626d185 'rename B' |/ o 1: 3ab5da9a5c01 'B' | o 0: 1994f17a630e 'A' $ hg rebase -s 5 -d 4 rebasing 5:af8ad1f97097 tip "E" note: not rebasing 5:af8ad1f97097 tip "E", its destination already has all its changes saved backup bundle to $TESTTMP/a/.hg/strip-backup/af8ad1f97097-c3e90708-rebase.hg $ hg tglog @ 4: 60f545c27784 'E' | | o 3: 032a9b75e83b 'rename A' | | | o 2: 220d0626d185 'rename B' |/ o 1: 3ab5da9a5c01 'B' | o 0: 1994f17a630e 'A' $ hg export tip # HG changeset patch # User user1 # Date 0 0 # Thu Jan 01 00:00:00 1970 +0000 # Node ID 60f545c277846e6bad309919bae3ae106f59cb39 # Parent 3ab5da9a5c01faa02c20f2ec4870a4f689c92da6 E diff -r 3ab5da9a5c01 -r 60f545c27784 z --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/z Thu Jan 01 00:00:00 1970 +0000 @@ -0,0 +1,2 @@ +a +blah $ cd .. $ hg init b $ cd b $ echo a > a $ hg ci -Am A adding a $ echo b > b $ hg ci -Am B adding b $ hg cp b b-copied $ hg ci -Am 'copy B' $ hg up -q -C 1 $ hg cp a a-copied $ hg ci -m 'copy A' created new head $ hg tglog @ 3: 0a8162ff18a8 'copy A' | | o 2: 39e588434882 'copy B' |/ o 1: 6c81ed0049f8 'B' | o 0: 1994f17a630e 'A' Copy is tracked: $ hg tlog -p --git -r tip 3: 0a8162ff18a8 'copy A' diff --git a/a b/a-copied copy from a copy to a-copied Rebase the revision containing the copy: $ hg rebase -s 3 -d 2 rebasing 3:0a8162ff18a8 tip "copy A" saved backup bundle to $TESTTMP/b/.hg/strip-backup/0a8162ff18a8-dd06302a-rebase.hg $ hg tglog @ 3: 98f6e6dbf45a 'copy A' | o 2: 39e588434882 'copy B' | o 1: 6c81ed0049f8 'B' | o 0: 1994f17a630e 'A' Copy is not lost: $ hg tlog -p --git -r tip 3: 98f6e6dbf45a 'copy A' diff --git a/a b/a-copied copy from a copy to a-copied Rebased revision does not contain information about b (issue3739) $ hg log -r 3 --debug changeset: 3:98f6e6dbf45ab54079c2237fbd11066a5c41a11d tag: tip phase: draft parent: 2:39e588434882ff77d01229d169cdc77f29e8855e parent: -1:0000000000000000000000000000000000000000 manifest: 3:2232f329d66fffe3930d43479ae624f66322b04d user: test date: Thu Jan 01 00:00:00 1970 +0000 files+: a-copied extra: branch=default extra: rebase_source=0a8162ff18a8900df8df8ef7ac0046955205613e description: copy A $ cd .. Test rebase across repeating renames: $ hg init repo $ cd repo $ echo testing > file1.txt $ hg add file1.txt $ hg ci -m "Adding file1" $ hg rename file1.txt file2.txt $ hg ci -m "Rename file1 to file2" $ echo Unrelated change > unrelated.txt $ hg add unrelated.txt $ hg ci -m "Unrelated change" $ hg rename file2.txt file1.txt $ hg ci -m "Rename file2 back to file1" $ hg update -r -2 1 files updated, 0 files merged, 1 files removed, 0 files unresolved $ echo Another unrelated change >> unrelated.txt $ hg ci -m "Another unrelated change" created new head $ hg tglog @ 4: b918d683b091 'Another unrelated change' | | o 3: 1ac17e43d8aa 'Rename file2 back to file1' |/ o 2: 480101d66d8d 'Unrelated change' | o 1: be44c61debd2 'Rename file1 to file2' | o 0: 8ce9a346991d 'Adding file1' $ hg rebase -s 4 -d 3 rebasing 4:b918d683b091 tip "Another unrelated change" saved backup bundle to $TESTTMP/repo/.hg/strip-backup/b918d683b091-3024bc57-rebase.hg $ hg diff --stat -c . unrelated.txt | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) $ cd .. Verify that copies get preserved (issue4192). $ hg init copy-gets-preserved $ cd copy-gets-preserved $ echo a > a $ hg add a $ hg commit --message "File a created" $ hg copy a b $ echo b > b $ hg commit --message "File b created as copy of a and modified" $ hg copy b c $ echo c > c $ hg commit --message "File c created as copy of b and modified" ## $ hg copy c d $ echo d > d $ hg commit --message "File d created as copy of c and modified (child of 327f772bc074)" Note that there are four entries in the log for d $ hg tglog --follow d @ 3: 6be224292cfa 'File d created as copy of c and modified (child of 327f772bc074)' | o 2: 327f772bc074 'File c created as copy of b and modified' | o 1: 79d255d24ad2 'File b created as copy of a and modified' | o 0: b220cd6d2326 'File a created' Update back to before we performed copies, and inject an unrelated change. $ hg update 0 0 files updated, 0 files merged, 3 files removed, 0 files unresolved $ echo unrelated > unrelated $ hg add unrelated $ hg commit --message "Unrelated file created" created new head $ hg update 4 0 files updated, 0 files merged, 0 files removed, 0 files unresolved Rebase the copies on top of the unrelated change. $ hg rebase --source 1 --dest 4 rebasing 1:79d255d24ad2 "File b created as copy of a and modified" rebasing 2:327f772bc074 "File c created as copy of b and modified" rebasing 3:6be224292cfa "File d created as copy of c and modified (child of 327f772bc074)" saved backup bundle to $TESTTMP/copy-gets-preserved/.hg/strip-backup/79d255d24ad2-a3e674e3-rebase.hg $ hg update 4 3 files updated, 0 files merged, 0 files removed, 0 files unresolved There should still be four entries in the log for d $ hg tglog --follow d @ 4: afbdde3a60d5 'File d created as copy of c and modified (child of af74b229bc02)' | o 3: af74b229bc02 'File c created as copy of b and modified' | o 2: 68bf06433839 'File b created as copy of a and modified' : o 0: b220cd6d2326 'File a created' Same steps as above, but with --collapse on rebase to make sure the copy records collapse correctly. $ hg co 1 0 files updated, 0 files merged, 3 files removed, 0 files unresolved $ echo more >> unrelated $ hg ci -m 'unrelated commit is unrelated' created new head $ hg rebase -s 2 --dest 5 --collapse rebasing 2:68bf06433839 "File b created as copy of a and modified" rebasing 3:af74b229bc02 "File c created as copy of b and modified" merging b and c to c rebasing 4:afbdde3a60d5 "File d created as copy of c and modified (child of af74b229bc02)" merging c and d to d saved backup bundle to $TESTTMP/copy-gets-preserved/.hg/strip-backup/68bf06433839-29d5057f-rebase.hg $ hg co tip 3 files updated, 0 files merged, 0 files removed, 0 files unresolved This should show both revision 3 and 0 since 'd' was transitively a copy of 'a'. $ hg tglog --follow d @ 3: 75708a266e56 'Collapsed revision : * File b created as copy of a and modified : * File c created as copy of b and modified : * File d created as copy of c and modified (child of af74b229bc02)' o 0: b220cd6d2326 'File a created' $ hg log -G -Tcompact @ 3[tip] 75708a266e56 1970-01-01 00:00 +0000 test | Collapsed revision | o 2 15258cf0cf10 1970-01-01 00:00 +0000 test | unrelated commit is unrelated | o 1 1d689898494b 1970-01-01 00:00 +0000 test | Unrelated file created | o 0 b220cd6d2326 1970-01-01 00:00 +0000 test File a created $ cd ..