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view tests/test-merge-types.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 | 38941a28406a |
children |
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#require symlink execbit $ tellmeabout() { > if [ -h $1 ]; then > echo $1 is a symlink: > $TESTDIR/readlink.py $1 > elif [ -x $1 ]; then > echo $1 is an executable file with content: > cat $1 > else > echo $1 is a plain file with content: > cat $1 > fi > } $ hg init test1 $ cd test1 $ echo a > a $ hg ci -Aqmadd $ chmod +x a $ hg ci -mexecutable $ hg up -q 0 $ rm a $ ln -s symlink a $ hg ci -msymlink created new head Symlink is local parent, executable is other: $ hg merge --debug resolving manifests branchmerge: True, force: False, partial: False ancestor: c334dc3be0da, local: 521a1e40188f+, remote: 3574f3e69b1c preserving a for resolve of a a: versions differ -> m tool internal:merge (for pattern a) can't handle symlinks couldn't find merge tool hgmerge no tool found to merge a picked tool ':prompt' for a (binary False symlink True changedelete False) file 'a' needs to be resolved. You can keep (l)ocal [working copy], take (o)ther [merge rev], or leave (u)nresolved. What do you want to do? u 0 files updated, 0 files merged, 0 files removed, 1 files unresolved use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon [1] $ tellmeabout a a is a symlink: a -> symlink $ hg resolve a --tool internal:other (no more unresolved files) $ tellmeabout a a is an executable file with content: a $ hg st M a ? a.orig Symlink is other parent, executable is local: $ hg update -C 1 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg merge --debug --tool :union resolving manifests branchmerge: True, force: False, partial: False ancestor: c334dc3be0da, local: 3574f3e69b1c+, remote: 521a1e40188f preserving a for resolve of a a: versions differ -> m picked tool ':union' for a (binary False symlink True changedelete False) merging a my a@3574f3e69b1c+ other a@521a1e40188f ancestor a@c334dc3be0da warning: internal :union cannot merge symlinks for a warning: conflicts while merging a! (edit, then use 'hg resolve --mark') 0 files updated, 0 files merged, 0 files removed, 1 files unresolved use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon [1] $ tellmeabout a a is an executable file with content: a $ hg update -C 1 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg merge --debug --tool :merge3 resolving manifests branchmerge: True, force: False, partial: False ancestor: c334dc3be0da, local: 3574f3e69b1c+, remote: 521a1e40188f preserving a for resolve of a a: versions differ -> m picked tool ':merge3' for a (binary False symlink True changedelete False) merging a my a@3574f3e69b1c+ other a@521a1e40188f ancestor a@c334dc3be0da warning: internal :merge3 cannot merge symlinks for a warning: conflicts while merging a! (edit, then use 'hg resolve --mark') 0 files updated, 0 files merged, 0 files removed, 1 files unresolved use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon [1] $ tellmeabout a a is an executable file with content: a $ hg update -C 1 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg merge --debug --tool :merge-local resolving manifests branchmerge: True, force: False, partial: False ancestor: c334dc3be0da, local: 3574f3e69b1c+, remote: 521a1e40188f preserving a for resolve of a a: versions differ -> m picked tool ':merge-local' for a (binary False symlink True changedelete False) merging a my a@3574f3e69b1c+ other a@521a1e40188f ancestor a@c334dc3be0da warning: internal :merge-local cannot merge symlinks for a 0 files updated, 0 files merged, 0 files removed, 1 files unresolved use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon [1] $ tellmeabout a a is an executable file with content: a $ hg update -C 1 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg merge --debug --tool :merge-other resolving manifests branchmerge: True, force: False, partial: False ancestor: c334dc3be0da, local: 3574f3e69b1c+, remote: 521a1e40188f preserving a for resolve of a a: versions differ -> m picked tool ':merge-other' for a (binary False symlink True changedelete False) merging a my a@3574f3e69b1c+ other a@521a1e40188f ancestor a@c334dc3be0da warning: internal :merge-other cannot merge symlinks for a 0 files updated, 0 files merged, 0 files removed, 1 files unresolved use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon [1] $ tellmeabout a a is an executable file with content: a Update to link without local change should get us a symlink (issue3316): $ hg up -C 0 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg up 1 files updated, 0 files merged, 0 files removed, 0 files unresolved updated to "521a1e40188f: symlink" 1 other heads for branch "default" $ hg st ? a.orig Update to link with local change should cause a merge prompt (issue3200): $ hg up -Cq 0 $ echo data > a $ HGMERGE= hg up -y --debug --config ui.merge= resolving manifests branchmerge: False, force: False, partial: False ancestor: c334dc3be0da, local: c334dc3be0da+, remote: 521a1e40188f preserving a for resolve of a a: versions differ -> m (couldn't find merge tool hgmerge|tool hgmerge can't handle symlinks) (re) no tool found to merge a picked tool ':prompt' for a (binary False symlink True changedelete False) file 'a' needs to be resolved. You can keep (l)ocal [working copy], take (o)ther [destination], or leave (u)nresolved. What do you want to do? u 0 files updated, 0 files merged, 0 files removed, 1 files unresolved use 'hg resolve' to retry unresolved file merges updated to "521a1e40188f: symlink" 1 other heads for branch "default" [1] $ hg diff --git diff --git a/a b/a old mode 120000 new mode 100644 --- a/a +++ b/a @@ -1,1 +1,1 @@ -symlink \ No newline at end of file +data Test only 'l' change - happens rarely, except when recovering from situations where that was what happened. $ hg init test2 $ cd test2 $ printf base > f $ hg ci -Aqm0 $ echo file > f $ echo content >> f $ hg ci -qm1 $ hg up -qr0 $ rm f $ ln -s base f $ hg ci -qm2 $ hg merge tool internal:merge (for pattern f) can't handle symlinks no tool found to merge f file 'f' needs to be resolved. You can keep (l)ocal [working copy], take (o)ther [merge rev], or leave (u)nresolved. What do you want to do? u 0 files updated, 0 files merged, 0 files removed, 1 files unresolved use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon [1] $ tellmeabout f f is a symlink: f -> base $ hg up -Cqr1 $ hg merge tool internal:merge (for pattern f) can't handle symlinks no tool found to merge f file 'f' needs to be resolved. You can keep (l)ocal [working copy], take (o)ther [merge rev], or leave (u)nresolved. What do you want to do? u 0 files updated, 0 files merged, 0 files removed, 1 files unresolved use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon [1] $ tellmeabout f f is a plain file with content: file content $ cd .. Test removed 'x' flag merged with change to symlink $ hg init test3 $ cd test3 $ echo f > f $ chmod +x f $ hg ci -Aqm0 $ chmod -x f $ hg ci -qm1 $ hg up -qr0 $ rm f $ ln -s dangling f $ hg ci -qm2 $ hg merge tool internal:merge (for pattern f) can't handle symlinks no tool found to merge f file 'f' needs to be resolved. You can keep (l)ocal [working copy], take (o)ther [merge rev], or leave (u)nresolved. What do you want to do? u 0 files updated, 0 files merged, 0 files removed, 1 files unresolved use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon [1] $ tellmeabout f f is a symlink: f -> dangling $ hg up -Cqr1 $ hg merge tool internal:merge (for pattern f) can't handle symlinks no tool found to merge f file 'f' needs to be resolved. You can keep (l)ocal [working copy], take (o)ther [merge rev], or leave (u)nresolved. What do you want to do? u 0 files updated, 0 files merged, 0 files removed, 1 files unresolved use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon [1] $ tellmeabout f f is a plain file with content: f Test removed 'x' flag merged with content change - both ways $ hg up -Cqr0 $ echo change > f $ hg ci -qm3 $ hg merge -r1 1 files updated, 0 files merged, 0 files removed, 0 files unresolved (branch merge, don't forget to commit) $ tellmeabout f f is a plain file with content: change $ hg up -qCr1 $ hg merge -r3 1 files updated, 0 files merged, 0 files removed, 0 files unresolved (branch merge, don't forget to commit) $ tellmeabout f f is a plain file with content: change $ cd .. Test merge with no common ancestor: a: just different b: x vs -, different (cannot calculate x, cannot ask merge tool) c: x vs -, same (cannot calculate x, merge tool is no good) d: x vs l, different e: x vs l, same f: - vs l, different g: - vs l, same h: l vs l, different (where same means the filelog entry is shared and there thus is an ancestor!) $ hg init test4 $ cd test4 $ echo 0 > 0 $ hg ci -Aqm0 $ echo 1 > a $ echo 1 > b $ chmod +x b $ echo 1 > bx $ chmod +x bx $ echo x > c $ chmod +x c $ echo 1 > d $ chmod +x d $ printf x > e $ chmod +x e $ echo 1 > f $ printf x > g $ ln -s 1 h $ hg ci -qAm1 $ hg up -qr0 $ echo 2 > a $ echo 2 > b $ echo 2 > bx $ chmod +x bx $ echo x > c $ ln -s 2 d $ ln -s x e $ ln -s 2 f $ ln -s x g $ ln -s 2 h $ hg ci -Aqm2 $ hg merge merging a warning: conflicts while merging a! (edit, then use 'hg resolve --mark') warning: cannot merge flags for b without common ancestor - keeping local flags merging b warning: conflicts while merging b! (edit, then use 'hg resolve --mark') merging bx warning: conflicts while merging bx! (edit, then use 'hg resolve --mark') warning: cannot merge flags for c without common ancestor - keeping local flags tool internal:merge (for pattern d) can't handle symlinks no tool found to merge d file 'd' needs to be resolved. You can keep (l)ocal [working copy], take (o)ther [merge rev], or leave (u)nresolved. What do you want to do? u tool internal:merge (for pattern f) can't handle symlinks no tool found to merge f file 'f' needs to be resolved. You can keep (l)ocal [working copy], take (o)ther [merge rev], or leave (u)nresolved. What do you want to do? u tool internal:merge (for pattern h) can't handle symlinks no tool found to merge h file 'h' needs to be resolved. You can keep (l)ocal [working copy], take (o)ther [merge rev], or leave (u)nresolved. What do you want to do? u 3 files updated, 0 files merged, 0 files removed, 6 files unresolved use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon [1] $ hg resolve -l U a U b U bx U d U f U h $ tellmeabout a a is a plain file with content: <<<<<<< working copy: 0c617753b41b - test: 2 2 ======= 1 >>>>>>> merge rev: 2e60aa20b912 - test: 1 $ tellmeabout b b is a plain file with content: <<<<<<< working copy: 0c617753b41b - test: 2 2 ======= 1 >>>>>>> merge rev: 2e60aa20b912 - test: 1 $ tellmeabout c c is a plain file with content: x $ tellmeabout d d is a symlink: d -> 2 $ tellmeabout e e is a symlink: e -> x $ tellmeabout f f is a symlink: f -> 2 $ tellmeabout g g is a symlink: g -> x $ tellmeabout h h is a symlink: h -> 2 $ hg up -Cqr1 $ hg merge merging a warning: conflicts while merging a! (edit, then use 'hg resolve --mark') warning: cannot merge flags for b without common ancestor - keeping local flags merging b warning: conflicts while merging b! (edit, then use 'hg resolve --mark') merging bx warning: conflicts while merging bx! (edit, then use 'hg resolve --mark') warning: cannot merge flags for c without common ancestor - keeping local flags tool internal:merge (for pattern d) can't handle symlinks no tool found to merge d file 'd' needs to be resolved. You can keep (l)ocal [working copy], take (o)ther [merge rev], or leave (u)nresolved. What do you want to do? u tool internal:merge (for pattern f) can't handle symlinks no tool found to merge f file 'f' needs to be resolved. You can keep (l)ocal [working copy], take (o)ther [merge rev], or leave (u)nresolved. What do you want to do? u tool internal:merge (for pattern h) can't handle symlinks no tool found to merge h file 'h' needs to be resolved. You can keep (l)ocal [working copy], take (o)ther [merge rev], or leave (u)nresolved. What do you want to do? u 3 files updated, 0 files merged, 0 files removed, 6 files unresolved use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon [1] $ tellmeabout a a is a plain file with content: <<<<<<< working copy: 2e60aa20b912 - test: 1 1 ======= 2 >>>>>>> merge rev: 0c617753b41b - test: 2 $ tellmeabout b b is an executable file with content: <<<<<<< working copy: 2e60aa20b912 - test: 1 1 ======= 2 >>>>>>> merge rev: 0c617753b41b - test: 2 $ tellmeabout c c is an executable file with content: x $ tellmeabout d d is an executable file with content: 1 $ tellmeabout e e is an executable file with content: x (no-eol) $ tellmeabout f f is a plain file with content: 1 $ tellmeabout g g is a plain file with content: x (no-eol) $ tellmeabout h h is a symlink: h -> 1 $ cd ..