Mercurial > hg
view tests/test-import-merge.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 | f1186c292d03 |
children | 2f2682f40ea0 |
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$ echo "[extensions]" >> $HGRCPATH $ echo "mq=" >> $HGRCPATH $ tipparents() { > hg parents --template "{rev}:{node|short} {desc|firstline}\n" -r tip > } Test import and merge diffs $ hg init repo $ cd repo $ echo a > a $ hg ci -Am adda adding a $ echo a >> a $ hg ci -m changea $ echo c > c $ hg ci -Am addc adding c $ hg up 0 1 files updated, 0 files merged, 1 files removed, 0 files unresolved $ echo b > b $ hg ci -Am addb adding b created new head $ hg up 1 1 files updated, 0 files merged, 1 files removed, 0 files unresolved $ hg merge 3 1 files updated, 0 files merged, 0 files removed, 0 files unresolved (branch merge, don't forget to commit) $ hg ci -m merge $ hg export . > ../merge.diff $ grep -v '^merge$' ../merge.diff > ../merge.nomsg.diff $ cd .. $ hg clone -r2 repo repo2 adding changesets adding manifests adding file changes added 3 changesets with 3 changes to 2 files new changesets 07f494440405:890ecaa90481 updating to branch default 2 files updated, 0 files merged, 0 files removed, 0 files unresolved $ cd repo2 $ hg pull -r3 ../repo pulling from ../repo searching for changes adding changesets adding manifests adding file changes added 1 changesets with 1 changes to 1 files (+1 heads) new changesets 102a90ea7b4a (run 'hg heads' to see heads, 'hg merge' to merge) Test without --exact and diff.p1 == workingdir.p1 $ hg up 1 0 files updated, 0 files merged, 1 files removed, 0 files unresolved $ cat > $TESTTMP/editor.sh <<EOF > env | grep HGEDITFORM > echo merge > \$1 > EOF $ HGEDITOR="sh $TESTTMP/editor.sh" hg import --edit ../merge.nomsg.diff applying ../merge.nomsg.diff HGEDITFORM=import.normal.merge $ tipparents 1:540395c44225 changea 3:102a90ea7b4a addb $ hg strip --no-backup tip 0 files updated, 0 files merged, 1 files removed, 0 files unresolved Test without --exact and diff.p1 != workingdir.p1 $ hg up 2 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg import ../merge.diff applying ../merge.diff warning: import the patch as a normal revision (use --exact to import the patch as a merge) $ tipparents 2:890ecaa90481 addc $ hg strip --no-backup tip 0 files updated, 0 files merged, 1 files removed, 0 files unresolved Test with --exact $ hg import --exact ../merge.diff applying ../merge.diff 0 files updated, 0 files merged, 1 files removed, 0 files unresolved $ tipparents 1:540395c44225 changea 3:102a90ea7b4a addb $ hg strip --no-backup tip 0 files updated, 0 files merged, 1 files removed, 0 files unresolved Test with --bypass and diff.p1 == workingdir.p1 $ hg up 1 0 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg import --bypass ../merge.diff applying ../merge.diff $ tipparents 1:540395c44225 changea 3:102a90ea7b4a addb $ hg strip --no-backup tip Test with --bypass and diff.p1 != workingdir.p1 $ hg up 2 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg import --bypass ../merge.diff applying ../merge.diff warning: import the patch as a normal revision (use --exact to import the patch as a merge) $ tipparents 2:890ecaa90481 addc $ hg strip --no-backup tip Test with --bypass and --exact $ hg import --bypass --exact ../merge.diff applying ../merge.diff $ tipparents 1:540395c44225 changea 3:102a90ea7b4a addb $ hg strip --no-backup tip $ cd .. Test that --exact on a bad header doesn't corrupt the repo (issue3616) $ hg init repo3 $ cd repo3 $ echo a>a $ hg ci -Aqm0 $ echo a>>a $ hg ci -m1 $ echo a>>a $ hg ci -m2 $ echo a>a $ echo b>>a $ echo a>>a $ hg ci -m3 $ hg export 2 | head -7 > ../a.patch $ hg export tip > out >>> apatch = open("../a.patch", "ab") >>> apatch.write(b"".join(open("out", 'rb').readlines()[7:])) and None $ cd .. $ hg clone -qr0 repo3 repo3-clone $ cd repo3-clone $ hg pull -qr1 ../repo3 $ hg import --exact ../a.patch applying ../a.patch 1 files updated, 0 files merged, 0 files removed, 0 files unresolved patching file a Hunk #1 succeeded at 1 with fuzz 1 (offset -1 lines). transaction abort! rollback completed abort: patch is damaged or loses information [255] $ hg verify checking changesets checking manifests crosschecking files in changesets and manifests checking files checked 2 changesets with 2 changes to 1 files