Mercurial > hg
view tests/test-simple-update.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 | 8d72e29ad1e0 |
children | 2f2682f40ea0 |
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$ hg init test $ cd test $ echo foo>foo $ hg addremove adding foo $ hg commit -m "1" $ hg verify checking changesets checking manifests crosschecking files in changesets and manifests checking files checked 1 changesets with 1 changes to 1 files $ hg clone . ../branch updating to branch default 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ cd ../branch $ hg co 0 files updated, 0 files merged, 0 files removed, 0 files unresolved $ echo bar>>foo $ hg commit -m "2" -d '1 0' $ cd ../test $ hg pull ../branch pulling from ../branch searching for changes adding changesets adding manifests adding file changes added 1 changesets with 1 changes to 1 files new changesets 84b9316f7b31 1 local changesets published (run 'hg update' to get a working copy) $ hg verify checking changesets checking manifests crosschecking files in changesets and manifests checking files checked 2 changesets with 2 changes to 1 files $ hg co 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ cat foo foo bar $ hg manifest --debug 6f4310b00b9a147241b071a60c28a650827fb03d 644 foo update to rev 0 with a date $ hg upd -d foo 0 abort: you can't specify a revision and a date [10] update by date $ hg update -d '<1970-01-01 00:00:02 +0000' found revision 1 from Thu Jan 01 00:00:01 1970 +0000 0 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg update -d '<1970-01-01 00:00:01 +0000' found revision 1 from Thu Jan 01 00:00:01 1970 +0000 0 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg update -d '<1970-01-01 00:00:00 +0000' found revision 0 from Thu Jan 01 00:00:00 1970 +0000 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg update -d '>1970-01-01 00:00:02 +0000' abort: revision matching date not found [10] $ hg update -d '>1970-01-01 00:00:01 +0000' found revision 1 from Thu Jan 01 00:00:01 1970 +0000 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg update -d '>1970-01-01 00:00:00 +0000' found revision 1 from Thu Jan 01 00:00:01 1970 +0000 0 files updated, 0 files merged, 0 files removed, 0 files unresolved update to default destination (with empty revspec) $ hg update -q null $ hg update 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg id 84b9316f7b31 tip $ hg update -q null $ hg update -r '' 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg id 84b9316f7b31 tip $ hg update -q null $ hg update '' 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg id 84b9316f7b31 tip $ cd .. update with worker processes #if no-windows $ cat <<EOF > forceworker.py > from mercurial import extensions, worker > def nocost(orig, ui, costperop, nops, threadsafe=True): > return worker._numworkers(ui) > 1 > def uisetup(ui): > extensions.wrapfunction(worker, 'worthwhile', nocost) > EOF $ hg init worker $ cd worker $ cat <<EOF >> .hg/hgrc > [extensions] > forceworker = $TESTTMP/forceworker.py > [worker] > numcpus = 4 > EOF $ for i in `"$PYTHON" $TESTDIR/seq.py 1 100`; do > echo $i > $i > done $ hg ci -qAm 'add 100 files' $ hg update null 0 files updated, 0 files merged, 100 files removed, 0 files unresolved $ hg update -v | grep 100 getting 100 100 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg status $ cd .. #endif