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view tests/test-http-clone-r.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 | d68618954ade |
| children | 2f2682f40ea0 |
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#require serve creating 'remote $ hg init remote $ cd remote $ hg unbundle "$TESTDIR/bundles/remote.hg" adding changesets adding manifests adding file changes added 9 changesets with 7 changes to 4 files (+1 heads) new changesets bfaf4b5cbf01:916f1afdef90 (9 drafts) (run 'hg heads' to see heads, 'hg merge' to merge) $ hg up tip 1 files updated, 0 files merged, 0 files removed, 0 files unresolved Starting server $ hg serve -p $HGPORT -E ../error.log -d --pid-file=../hg1.pid $ cd .. $ cat hg1.pid >> $DAEMON_PIDS clone remote via stream $ for i in 0 1 2 3 4 5 6 7 8; do > hg clone -r "$i" http://localhost:$HGPORT/ test-"$i" > if cd test-"$i"; then > hg verify > cd .. > fi > done adding changesets adding manifests adding file changes added 1 changesets with 1 changes to 1 files new changesets bfaf4b5cbf01 updating to branch default 1 files updated, 0 files merged, 0 files removed, 0 files unresolved checking changesets checking manifests crosschecking files in changesets and manifests checking files checked 1 changesets with 1 changes to 1 files adding changesets adding manifests adding file changes added 2 changesets with 2 changes to 1 files new changesets bfaf4b5cbf01:21f32785131f updating to branch default 1 files updated, 0 files merged, 0 files removed, 0 files unresolved checking changesets checking manifests crosschecking files in changesets and manifests checking files checked 2 changesets with 2 changes to 1 files adding changesets adding manifests adding file changes added 3 changesets with 3 changes to 1 files new changesets bfaf4b5cbf01:4ce51a113780 updating to branch default 1 files updated, 0 files merged, 0 files removed, 0 files unresolved checking changesets checking manifests crosschecking files in changesets and manifests checking files checked 3 changesets with 3 changes to 1 files adding changesets adding manifests adding file changes added 4 changesets with 4 changes to 1 files new changesets bfaf4b5cbf01:93ee6ab32777 updating to branch default 1 files updated, 0 files merged, 0 files removed, 0 files unresolved checking changesets checking manifests crosschecking files in changesets and manifests checking files checked 4 changesets with 4 changes to 1 files adding changesets adding manifests adding file changes added 2 changesets with 2 changes to 1 files new changesets bfaf4b5cbf01:c70afb1ee985 updating to branch default 1 files updated, 0 files merged, 0 files removed, 0 files unresolved checking changesets checking manifests crosschecking files in changesets and manifests checking files checked 2 changesets with 2 changes to 1 files adding changesets adding manifests adding file changes added 3 changesets with 3 changes to 1 files new changesets bfaf4b5cbf01:f03ae5a9b979 updating to branch default 1 files updated, 0 files merged, 0 files removed, 0 files unresolved checking changesets checking manifests crosschecking files in changesets and manifests checking files checked 3 changesets with 3 changes to 1 files adding changesets adding manifests adding file changes added 4 changesets with 5 changes to 2 files new changesets bfaf4b5cbf01:095cb14b1b4d updating to branch default 2 files updated, 0 files merged, 0 files removed, 0 files unresolved checking changesets checking manifests crosschecking files in changesets and manifests checking files checked 4 changesets with 5 changes to 2 files adding changesets adding manifests adding file changes added 5 changesets with 6 changes to 3 files new changesets bfaf4b5cbf01:faa2e4234c7a updating to branch default 2 files updated, 0 files merged, 0 files removed, 0 files unresolved checking changesets checking manifests crosschecking files in changesets and manifests checking files checked 5 changesets with 6 changes to 3 files adding changesets adding manifests adding file changes added 5 changesets with 5 changes to 2 files new changesets bfaf4b5cbf01:916f1afdef90 updating to branch default 1 files updated, 0 files merged, 0 files removed, 0 files unresolved checking changesets checking manifests crosschecking files in changesets and manifests checking files checked 5 changesets with 5 changes to 2 files $ cd test-8 $ hg pull ../test-7 pulling from ../test-7 searching for changes adding changesets adding manifests adding file changes added 4 changesets with 2 changes to 3 files (+1 heads) new changesets c70afb1ee985:faa2e4234c7a (run 'hg heads' to see heads, 'hg merge' to merge) $ hg verify checking changesets checking manifests crosschecking files in changesets and manifests checking files checked 9 changesets with 7 changes to 4 files $ cd .. $ cd test-1 $ hg pull -r 4 http://localhost:$HGPORT/ pulling from http://localhost:$HGPORT/ searching for changes adding changesets adding manifests adding file changes added 1 changesets with 0 changes to 0 files (+1 heads) new changesets c70afb1ee985 (run 'hg heads' to see heads, 'hg merge' to merge) $ hg verify checking changesets checking manifests crosschecking files in changesets and manifests checking files checked 3 changesets with 2 changes to 1 files $ hg pull http://localhost:$HGPORT/ pulling from http://localhost:$HGPORT/ searching for changes adding changesets adding manifests adding file changes added 6 changesets with 5 changes to 4 files new changesets 4ce51a113780:916f1afdef90 (run 'hg update' to get a working copy) $ cd .. $ cd test-2 $ hg pull -r 5 http://localhost:$HGPORT/ pulling from http://localhost:$HGPORT/ searching for changes adding changesets adding manifests adding file changes added 2 changesets with 0 changes to 0 files (+1 heads) new changesets c70afb1ee985:f03ae5a9b979 (run 'hg heads' to see heads, 'hg merge' to merge) $ hg verify checking changesets checking manifests crosschecking files in changesets and manifests checking files checked 5 changesets with 3 changes to 1 files $ hg pull http://localhost:$HGPORT/ pulling from http://localhost:$HGPORT/ searching for changes adding changesets adding manifests adding file changes added 4 changesets with 4 changes to 4 files new changesets 93ee6ab32777:916f1afdef90 (run 'hg update' to get a working copy) $ hg verify checking changesets checking manifests crosschecking files in changesets and manifests checking files checked 9 changesets with 7 changes to 4 files $ cd .. no default destination if url has no path: $ hg clone http://localhost:$HGPORT/ abort: empty destination path is not valid [10] $ cat error.log