Mercurial > hg
view tests/test-bookmarks-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 | 8197b395710e |
children | 55c6ebd11cb9 |
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# init $ hg init $ echo a > a $ hg add a $ hg commit -m'a' $ echo b > b $ hg add b $ hg commit -m'b' $ hg up -C 0 0 files updated, 0 files merged, 1 files removed, 0 files unresolved $ echo c > c $ hg add c $ hg commit -m'c' created new head # test merging of diverged bookmarks $ hg bookmark -r 1 "c@diverge" $ hg bookmark -r 1 b $ hg bookmark c $ hg bookmarks b 1:d2ae7f538514 * c 2:d36c0562f908 c@diverge 1:d2ae7f538514 $ hg merge "c@diverge" 1 files updated, 0 files merged, 0 files removed, 0 files unresolved (branch merge, don't forget to commit) $ hg commit -m'merge' $ hg bookmarks b 1:d2ae7f538514 * c 3:b8f96cf4688b $ hg up -C 3 0 files updated, 0 files merged, 0 files removed, 0 files unresolved (leaving bookmark c) $ echo d > d $ hg add d $ hg commit -m'd' $ hg up -C 3 0 files updated, 0 files merged, 1 files removed, 0 files unresolved $ echo e > e $ hg add e $ hg commit -m'e' created new head $ hg up -C 5 0 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg bookmark e $ hg bookmarks b 1:d2ae7f538514 c 3:b8f96cf4688b * e 5:26bee9c5bcf3 # the picked side is bookmarked $ hg up -C 4 1 files updated, 0 files merged, 1 files removed, 0 files unresolved (leaving bookmark e) $ hg merge abort: heads are bookmarked - please merge with an explicit rev (run 'hg heads' to see all heads, specify rev with -r) [255] # our revision is bookmarked $ hg up -C e 1 files updated, 0 files merged, 1 files removed, 0 files unresolved (activating bookmark e) $ hg merge abort: no matching bookmark to merge - please merge with an explicit rev or bookmark (run 'hg heads' to see all heads, specify rev with -r) [255] # merge bookmark heads $ hg up -C 4 1 files updated, 0 files merged, 1 files removed, 0 files unresolved (leaving bookmark e) $ echo f > f $ hg commit -Am "f" adding f $ hg bookmarks -r 4 "e@diverged" $ hg up -q -C "e@diverged" $ hg merge 1 files updated, 0 files merged, 0 files removed, 0 files unresolved (branch merge, don't forget to commit) $ hg parents changeset: 4:a0546fcfe0fb bookmark: e@diverged user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: d changeset: 5:26bee9c5bcf3 bookmark: e parent: 3:b8f96cf4688b user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: e $ hg up -C e 1 files updated, 0 files merged, 1 files removed, 0 files unresolved (activating bookmark e) $ hg bookmarks b 1:d2ae7f538514 c 3:b8f96cf4688b * e 5:26bee9c5bcf3 e@diverged 4:a0546fcfe0fb $ hg merge 1 files updated, 0 files merged, 0 files removed, 0 files unresolved (branch merge, don't forget to commit) $ hg commit -m'merge' $ hg bookmarks b 1:d2ae7f538514 c 3:b8f96cf4688b * e 7:ca784329f0ba # test warning when all heads are inactive bookmarks $ hg up -C 6 1 files updated, 0 files merged, 1 files removed, 0 files unresolved (leaving bookmark e) $ echo g > g $ hg commit -Am 'g' adding g $ hg bookmark -i g $ hg bookmarks b 1:d2ae7f538514 c 3:b8f96cf4688b e 7:ca784329f0ba g 8:04dd21731d95 $ hg heads changeset: 8:04dd21731d95 bookmark: g tag: tip parent: 6:be381d1126a0 user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: g changeset: 7:ca784329f0ba bookmark: e parent: 5:26bee9c5bcf3 parent: 4:a0546fcfe0fb user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: merge $ hg merge abort: heads are bookmarked - please merge with an explicit rev (run 'hg heads' to see all heads, specify rev with -r) [255]