tests/test-strip-cross.t

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

test stripping of filelogs where the linkrev doesn't always increase

  $ echo '[extensions]' >> $HGRCPATH
  $ echo 'strip =' >> $HGRCPATH
  $ commit()
  > {
  >     hg up -qC null
  >     count=1
  >     for i in "$@"; do
  >         for f in $i; do
  >             mkdir -p `dirname $f`
  >             echo $count > $f
  >         done
  >         count=`expr $count + 1`
  >     done
  >     hg commit -qAm "$*"
  > }

2 1 0 2 0 1 2

  $ mkdir files
  $ cd files
  $ hg init orig
  $ cd orig
  $ commit '201 210'
  $ commit '102 120' '210'
  $ commit '021'
  $ commit '201' '021 120'
  $ commit '012 021' '102 201' '120 210'
  $ commit '102 120' '012 210' '021 201'
  $ commit '201 210' '021 120' '012 102'
  $ cd ..
  $ hg clone -q -U -r 4 -r 5 -r 6 orig crossed
  $ cd crossed

  $ for i in 012 021 102 120 201 210; do
  >     echo $i
  >     hg debugindex $i
  >     echo
  > done
  012
     rev linkrev nodeid       p1           p2
       0       0 b8e02f643373 000000000000 000000000000
       1       1 5d9299349fc0 000000000000 000000000000
       2       2 2661d26c6496 000000000000 000000000000
  
  021
     rev linkrev nodeid       p1           p2
       0       0 b8e02f643373 000000000000 000000000000
       1       2 5d9299349fc0 000000000000 000000000000
       2       1 2661d26c6496 000000000000 000000000000
  
  102
     rev linkrev nodeid       p1           p2
       0       1 b8e02f643373 000000000000 000000000000
       1       0 5d9299349fc0 000000000000 000000000000
       2       2 2661d26c6496 000000000000 000000000000
  
  120
     rev linkrev nodeid       p1           p2
       0       1 b8e02f643373 000000000000 000000000000
       1       2 5d9299349fc0 000000000000 000000000000
       2       0 2661d26c6496 000000000000 000000000000
  
  201
     rev linkrev nodeid       p1           p2
       0       2 b8e02f643373 000000000000 000000000000
       1       0 5d9299349fc0 000000000000 000000000000
       2       1 2661d26c6496 000000000000 000000000000
  
  210
     rev linkrev nodeid       p1           p2
       0       2 b8e02f643373 000000000000 000000000000
       1       1 5d9299349fc0 000000000000 000000000000
       2       0 2661d26c6496 000000000000 000000000000
  
  $ cd ..
  $ for i in 0 1 2; do
  >     hg clone -q -U --pull crossed $i
  >     echo "% Trying to strip revision $i"
  >     hg --cwd $i strip $i
  >     echo "% Verifying"
  >     hg --cwd $i verify
  >     echo
  > done
  % Trying to strip revision 0
  saved backup bundle to $TESTTMP/files/0/.hg/strip-backup/cbb8c2f0a2e3-239800b9-backup.hg
  % Verifying
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  checked 2 changesets with 12 changes to 6 files
  
  % Trying to strip revision 1
  saved backup bundle to $TESTTMP/files/1/.hg/strip-backup/124ecc0cbec9-6104543f-backup.hg
  % Verifying
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  checked 2 changesets with 12 changes to 6 files
  
  % Trying to strip revision 2
  saved backup bundle to $TESTTMP/files/2/.hg/strip-backup/f6439b304a1a-c6505a5f-backup.hg
  % Verifying
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  checked 2 changesets with 12 changes to 6 files
  
  $ cd ..

Do a similar test where the manifest revlog has unordered linkrevs
  $ mkdir manifests
  $ cd manifests
  $ hg init orig
  $ cd orig
  $ commit 'file'
  $ commit 'other'
  $ commit '' 'other'
  $ HGUSER=another-user; export HGUSER
  $ commit 'file'
  $ commit 'other' 'file'
  $ cd ..
  $ hg clone -q -U -r 1 -r 2 -r 3 -r 4 orig crossed
  $ cd crossed
  $ hg debugindex --manifest
     rev linkrev nodeid       p1           p2
       0       2 6bbc6fee55c2 000000000000 000000000000
       1       0 1c556153fe54 000000000000 000000000000
       2       1 1f76dba919fd 000000000000 000000000000
       3       3 bbee06ad59d5 000000000000 000000000000

  $ cd ..
  $ for i in 2 3; do
  >     hg clone -q -U --pull crossed $i
  >     echo "% Trying to strip revision $i"
  >     hg --cwd $i strip $i
  >     echo "% Verifying"
  >     hg --cwd $i verify
  >     echo
  > done
  % Trying to strip revision 2
  saved backup bundle to $TESTTMP/manifests/2/.hg/strip-backup/f3015ad03c03-4d98bdc2-backup.hg
  % Verifying
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  checked 3 changesets with 3 changes to 2 files
  
  % Trying to strip revision 3
  saved backup bundle to $TESTTMP/manifests/3/.hg/strip-backup/9632aa303aa4-69192e3f-backup.hg
  % Verifying
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  checked 3 changesets with 3 changes to 2 files
  
  $ cd ..

Now a similar test for a non-root manifest revlog
  $ cat >> $HGRCPATH <<EOF
  > [experimental]
  > treemanifests = yes
  > EOF
  $ mkdir treemanifests
  $ cd treemanifests
  $ 
  $ hg --config experimental.treemanifest=True init orig
  $ cd orig
  $ commit 'dir/file'
  $ commit 'dir/other'
  $ commit '' 'dir/other'
  $ HGUSER=yet-another-user; export HGUSER
  $ commit 'otherdir dir/file'
  $ commit 'otherdir dir/other' 'otherdir dir/file'
  $ cd ..
  $ hg --config experimental.treemanifest=True clone -q -U -r 1 -r 2 -r 3 -r 4 orig crossed
  $ cd crossed
  $ hg debugindex --dir dir
     rev linkrev nodeid       p1           p2
       0       2 6bbc6fee55c2 000000000000 000000000000
       1       0 1c556153fe54 000000000000 000000000000
       2       1 1f76dba919fd 000000000000 000000000000
       3       3 bbee06ad59d5 000000000000 000000000000

  $ cd ..
  $ for i in 2 3; do
  >     hg --config experimental.treemanifest=True clone -q -U --pull crossed $i
  >     echo "% Trying to strip revision $i"
  >     hg --cwd $i strip $i
  >     echo "% Verifying"
  >     hg --cwd $i verify
  >     echo
  > done
  % Trying to strip revision 2
  saved backup bundle to $TESTTMP/treemanifests/2/.hg/strip-backup/145f5c75f9ac-a105cfbe-backup.hg
  % Verifying
  checking changesets
  checking manifests
  checking directory manifests
  crosschecking files in changesets and manifests
  checking files
  checked 3 changesets with 4 changes to 3 files
  
  % Trying to strip revision 3
  saved backup bundle to $TESTTMP/treemanifests/3/.hg/strip-backup/e4e3de5c3cb2-f4c70376-backup.hg
  % Verifying
  checking changesets
  checking manifests
  checking directory manifests
  crosschecking files in changesets and manifests
  checking files
  checked 3 changesets with 4 changes to 3 files
  
  $ cd ..