Mercurial > hg
view tests/test-rebase-newancestor.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 | 9989a276712f |
children | 2cf264e9aa75 |
line wrap: on
line source
$ cat >> $HGRCPATH <<EOF > [extensions] > rebase= > drawdag=$TESTDIR/drawdag.py > [alias] > tglog = log -G --template "{rev}: {node|short} '{desc}' {branches}\n" > EOF $ hg init repo $ cd repo $ echo A > a $ echo >> a $ hg ci -Am A adding a $ echo B > a $ echo >> a $ hg ci -m B $ echo C > a $ echo >> a $ hg ci -m C $ hg up -q -C 0 $ echo D >> a $ hg ci -Am AD created new head $ hg tglog @ 3: 3878212183bd 'AD' | | o 2: 30ae917c0e4f 'C' | | | o 1: 0f4f7cb4f549 'B' |/ o 0: 1e635d440a73 'A' $ hg rebase -s 1 -d 3 rebasing 1:0f4f7cb4f549 "B" merging a rebasing 2:30ae917c0e4f "C" merging a saved backup bundle to $TESTTMP/repo/.hg/strip-backup/0f4f7cb4f549-82b3b163-rebase.hg $ hg tglog o 3: 25773bc4b4b0 'C' | o 2: c09015405f75 'B' | @ 1: 3878212183bd 'AD' | o 0: 1e635d440a73 'A' $ cd .. Test rebasing of merges with ancestors of the rebase destination - a situation that often happens when trying to recover from repeated merging with a mainline branch. The test case creates a dev branch that contains a couple of merges from the default branch. When rebasing to the default branch, these merges would be merges with ancestors on the same branch. The merges _could_ contain some interesting conflict resolutions or additional changes in the merge commit, but that is mixed up with the actual merge stuff and there is in general no way to separate them. $ hg init ancestor-merge $ cd ancestor-merge $ touch f-default $ hg ci -Aqm 'default: create f-default' $ hg branch -q dev $ hg ci -qm 'dev: create branch' $ echo stuff > f-dev $ hg ci -Aqm 'dev: f-dev stuff' $ hg up -q default $ echo stuff > f-default $ hg ci -m 'default: f-default stuff' $ hg up -q dev $ hg merge -q default $ hg ci -m 'dev: merge default' $ hg up -q default $ hg rm f-default $ hg ci -m 'default: remove f-default' $ hg up -q dev $ hg merge -q default $ hg ci -m 'dev: merge default' $ hg up -q default $ echo stuff > f-other $ hg ci -Aqm 'default: f-other stuff' $ hg tglog @ 7: e08089805d82 'default: f-other stuff' | | o 6: 010ced67e558 'dev: merge default' dev |/| o | 5: 462860db70a1 'default: remove f-default' | | | o 4: 4b019212aaf6 'dev: merge default' dev |/| o | 3: f157ecfd2b6b 'default: f-default stuff' | | | o 2: ec2c14fb2984 'dev: f-dev stuff' dev | | | o 1: 1d1a643d390e 'dev: create branch' dev |/ o 0: e90e8eb90b6f 'default: create f-default' $ hg clone -qU . ../ancestor-merge-2 Full rebase all the way back from branching point: $ hg rebase -r 'only(dev,default)' -d default --config ui.interactive=True << EOF > c > EOF rebasing 1:1d1a643d390e "dev: create branch" note: not rebasing 1:1d1a643d390e "dev: create branch", its destination already has all its changes rebasing 2:ec2c14fb2984 "dev: f-dev stuff" rebasing 4:4b019212aaf6 "dev: merge default" note: not rebasing 4:4b019212aaf6 "dev: merge default", its destination already has all its changes rebasing 6:010ced67e558 "dev: merge default" note: not rebasing 6:010ced67e558 "dev: merge default", its destination already has all its changes saved backup bundle to $TESTTMP/ancestor-merge/.hg/strip-backup/1d1a643d390e-4a6f6d17-rebase.hg $ hg tglog o 4: 3e075b1c0a40 'dev: f-dev stuff' | @ 3: e08089805d82 'default: f-other stuff' | o 2: 462860db70a1 'default: remove f-default' | o 1: f157ecfd2b6b 'default: f-default stuff' | o 0: e90e8eb90b6f 'default: create f-default' Grafty cherry picking rebasing: $ cd ../ancestor-merge-2 $ hg phase -fdr0: $ hg rebase -r 'children(only(dev,default))' -d default --config ui.interactive=True << EOF > c > EOF rebasing 2:ec2c14fb2984 "dev: f-dev stuff" rebasing 4:4b019212aaf6 "dev: merge default" abort: rebasing 4:4b019212aaf6 will include unwanted changes from 1:1d1a643d390e [10] $ cd .. Test order of parents of rebased merged with un-rebased changes as p1. $ hg init parentorder $ cd parentorder $ touch f $ hg ci -Aqm common $ touch change $ hg ci -Aqm change $ touch target $ hg ci -Aqm target $ hg up -qr 0 $ touch outside $ hg ci -Aqm outside $ hg merge -qr 1 $ hg ci -m 'merge p1 3=outside p2 1=ancestor' $ hg par changeset: 4:6990226659be tag: tip parent: 3:f59da8fc0fcf parent: 1:dd40c13f7a6f user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: merge p1 3=outside p2 1=ancestor $ hg up -qr 1 $ hg merge -qr 3 $ hg ci -qm 'merge p1 1=ancestor p2 3=outside' $ hg par changeset: 5:a57575f79074 tag: tip parent: 1:dd40c13f7a6f parent: 3:f59da8fc0fcf user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: merge p1 1=ancestor p2 3=outside $ hg tglog @ 5: a57575f79074 'merge p1 1=ancestor p2 3=outside' |\ +---o 4: 6990226659be 'merge p1 3=outside p2 1=ancestor' | |/ | o 3: f59da8fc0fcf 'outside' | | +---o 2: a60552eb93fb 'target' | | o | 1: dd40c13f7a6f 'change' |/ o 0: 02f0f58d5300 'common' $ hg rebase -r 4 -d 2 rebasing 4:6990226659be "merge p1 3=outside p2 1=ancestor" saved backup bundle to $TESTTMP/parentorder/.hg/strip-backup/6990226659be-4d67a0d3-rebase.hg $ hg tip changeset: 5:cca50676b1c5 tag: tip parent: 2:a60552eb93fb parent: 3:f59da8fc0fcf user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: merge p1 3=outside p2 1=ancestor $ hg rebase -r 4 -d 2 rebasing 4:a57575f79074 "merge p1 1=ancestor p2 3=outside" saved backup bundle to $TESTTMP/parentorder/.hg/strip-backup/a57575f79074-385426e5-rebase.hg $ hg tip changeset: 5:f9daf77ffe76 tag: tip parent: 2:a60552eb93fb parent: 3:f59da8fc0fcf user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: merge p1 1=ancestor p2 3=outside $ hg tglog @ 5: f9daf77ffe76 'merge p1 1=ancestor p2 3=outside' |\ +---o 4: cca50676b1c5 'merge p1 3=outside p2 1=ancestor' | |/ | o 3: f59da8fc0fcf 'outside' | | o | 2: a60552eb93fb 'target' | | o | 1: dd40c13f7a6f 'change' |/ o 0: 02f0f58d5300 'common' rebase of merge of ancestors $ hg up -qr 2 $ hg merge -qr 3 $ echo 'other change while merging future "rebase ancestors"' > other $ hg ci -Aqm 'merge rebase ancestors' $ hg rebase -d 5 -v rebasing 6:4c5f12f25ebe tip "merge rebase ancestors" resolving manifests removing other resolving manifests getting other committing files: other committing manifest committing changelog rebase merging completed 1 changesets found uncompressed size of bundle content: 199 (changelog) 216 (manifests) 182 other saved backup bundle to $TESTTMP/parentorder/.hg/strip-backup/4c5f12f25ebe-f46990e5-rebase.hg 1 changesets found uncompressed size of bundle content: 254 (changelog) 167 (manifests) 182 other adding branch adding changesets adding manifests adding file changes added 1 changesets with 1 changes to 1 files rebase completed $ hg tglog @ 6: 113755df812b 'merge rebase ancestors' | o 5: f9daf77ffe76 'merge p1 1=ancestor p2 3=outside' |\ +---o 4: cca50676b1c5 'merge p1 3=outside p2 1=ancestor' | |/ | o 3: f59da8fc0fcf 'outside' | | o | 2: a60552eb93fb 'target' | | o | 1: dd40c13f7a6f 'change' |/ o 0: 02f0f58d5300 'common' Due to the limitation of 3-way merge algorithm (1 merge base), rebasing a merge may include unwanted content: $ hg init $TESTTMP/dual-merge-base1 $ cd $TESTTMP/dual-merge-base1 $ hg debugdrawdag <<'EOS' > F > /| > D E > | | > B C > |/ > A Z > |/ > R > EOS $ hg rebase -r D+E+F -d Z rebasing 5:5f2c926dfecf D "D" rebasing 6:b296604d9846 E "E" rebasing 7:caa9781e507d F tip "F" abort: rebasing 7:caa9781e507d will include unwanted changes from 4:d6003a550c2c or 3:c1e6b162678d [10] The warning does not get printed if there is no unwanted change detected: $ hg init $TESTTMP/dual-merge-base2 $ cd $TESTTMP/dual-merge-base2 $ hg debugdrawdag <<'EOS' > D > /| > B C > |/ > A Z > |/ > R > EOS $ hg rebase -r B+C+D -d Z rebasing 3:c1e6b162678d B "B" rebasing 4:d6003a550c2c C "C" rebasing 5:c8f78076273e D tip "D" saved backup bundle to $TESTTMP/dual-merge-base2/.hg/strip-backup/d6003a550c2c-6f1424b6-rebase.hg $ hg manifest -r 'desc(D)' B C R Z The merge base could be different from old p1 (changed parent becomes new p1): $ hg init $TESTTMP/chosen-merge-base1 $ cd $TESTTMP/chosen-merge-base1 $ hg debugdrawdag <<'EOS' > F > /| > D E > | | > B C Z > EOS $ hg rebase -r D+F -d Z rebasing 3:004dc1679908 D "D" rebasing 5:4be4cbf6f206 F tip "F" saved backup bundle to $TESTTMP/chosen-merge-base1/.hg/strip-backup/004dc1679908-06a66a3c-rebase.hg $ hg manifest -r 'desc(F)' C D E Z $ hg log -r `hg log -r 'desc(F)' -T '{p1node}'` -T '{desc}\n' D $ hg init $TESTTMP/chosen-merge-base2 $ cd $TESTTMP/chosen-merge-base2 $ hg debugdrawdag <<'EOS' > F > /| > D E > | | > B C Z > EOS $ hg rebase -r E+F -d Z rebasing 4:974e4943c210 E "E" rebasing 5:4be4cbf6f206 F tip "F" saved backup bundle to $TESTTMP/chosen-merge-base2/.hg/strip-backup/974e4943c210-b2874da5-rebase.hg $ hg manifest -r 'desc(F)' B D E Z $ hg log -r `hg log -r 'desc(F)' -T '{p1node}'` -T '{desc}\n' E