Mercurial > hg
view tests/test-subrepo-missing.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 | 7f633432ca92 |
children | 2f2682f40ea0 |
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$ hg init repo $ cd repo $ hg init subrepo $ echo a > subrepo/a $ hg -R subrepo ci -Am adda adding a $ echo 'subrepo = subrepo' > .hgsub $ hg ci -Am addsubrepo adding .hgsub $ echo b > subrepo/b $ hg -R subrepo ci -Am addb adding b $ hg ci -m updatedsub ignore blanklines in .hgsubstate >>> open('.hgsubstate', 'wb').write(b'\n\n \t \n \n') and None $ hg st --subrepos M .hgsubstate $ hg revert -qC .hgsubstate abort more gracefully on .hgsubstate parsing error $ cp .hgsubstate .hgsubstate.old >>> open('.hgsubstate', 'wb').write(b'\ninvalid') and None $ hg st --subrepos --cwd $TESTTMP -R $TESTTMP/repo abort: invalid subrepository revision specifier in 'repo/.hgsubstate' line 2 [255] $ mv .hgsubstate.old .hgsubstate delete .hgsub and revert it $ rm .hgsub $ hg revert .hgsub warning: subrepo spec file '.hgsub' not found warning: subrepo spec file '.hgsub' not found delete .hgsubstate and revert it $ rm .hgsubstate $ hg revert .hgsubstate delete .hgsub and update $ rm .hgsub $ hg up 0 --cwd $TESTTMP -R $TESTTMP/repo warning: subrepo spec file 'repo/.hgsub' not found warning: subrepo spec file 'repo/.hgsub' not found 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg st warning: subrepo spec file '.hgsub' not found ! .hgsub $ ls -A subrepo .hg a delete .hgsubstate and update $ hg up -C warning: subrepo spec file '.hgsub' not found warning: subrepo spec file '.hgsub' not found 2 files updated, 0 files merged, 0 files removed, 0 files unresolved $ rm .hgsubstate $ hg up 0 other [destination] changed .hgsubstate which local [working copy] deleted use (c)hanged version or leave (d)eleted? c 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg st $ ls -A subrepo .hg a Enable obsolete $ cat >> $HGRCPATH << EOF > [ui] > logtemplate= {rev}:{node|short} {desc|firstline} > [phases] > publish=False > [experimental] > evolution.createmarkers=True > EOF check that we can update parent repo with missing (amended) subrepo revision $ hg up --repository subrepo -r tip 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg ci -m "updated subrepo to tip" created new head $ cd subrepo $ hg update -r tip 0 files updated, 0 files merged, 0 files removed, 0 files unresolved $ echo foo > a $ hg commit --amend -m "addb (amended)" $ cd .. $ hg update --clean . revision 102a90ea7b4a in subrepository "subrepo" is hidden 1 files updated, 0 files merged, 0 files removed, 0 files unresolved check that --hidden is propagated to the subrepo $ hg -R subrepo up tip 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg ci -m 'commit with amended subrepo' $ echo bar > subrepo/a $ hg -R subrepo ci --amend -m "amend a (again)" $ hg --hidden cat subrepo/a foo verify will warn if locked-in subrepo revisions are hidden or missing $ hg ci -m "amended subrepo (again)" $ hg --config extensions.strip= --hidden strip -R subrepo -qr 'tip' --config devel.strip-obsmarkers=no $ hg verify checking changesets checking manifests crosschecking files in changesets and manifests checking files checked 5 changesets with 5 changes to 2 files checking subrepo links subrepo 'subrepo' is hidden in revision a66de08943b6 subrepo 'subrepo' is hidden in revision 674d05939c1e subrepo 'subrepo' not found in revision a7d05d9055a4 verifying shouldn't init a new subrepo if the reference doesn't exist $ mv subrepo b $ hg verify checking changesets checking manifests crosschecking files in changesets and manifests checking files checked 5 changesets with 5 changes to 2 files checking subrepo links 0: repository $TESTTMP/repo/subrepo not found 1: repository $TESTTMP/repo/subrepo not found 3: repository $TESTTMP/repo/subrepo not found 4: repository $TESTTMP/repo/subrepo not found $ ls -A .hg .hgsub .hgsubstate b $ mv b subrepo $ cd ..