view tests/test-bundle-phases.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

  $ cat >> $HGRCPATH <<EOF
  > [experimental]
  > bundle-phases=yes
  > [extensions]
  > strip=
  > drawdag=$TESTDIR/drawdag.py
  > EOF

Set up repo with linear history
  $ hg init linear
  $ cd linear
  $ hg debugdrawdag <<'EOF'
  > E
  > |
  > D
  > |
  > C
  > |
  > B
  > |
  > A
  > EOF
  $ hg phase --public A
  $ hg phase --force --secret D
  $ hg log -G -T '{desc} {phase}\n'
  o  E secret
  |
  o  D secret
  |
  o  C draft
  |
  o  B draft
  |
  o  A public
  
Phases are restored when unbundling
  $ hg bundle --base B -r E bundle
  3 changesets found
  $ hg debugbundle bundle
  Stream params: {Compression: BZ}
  changegroup -- {nbchanges: 3, targetphase: 2, version: 02} (mandatory: True)
      26805aba1e600a82e93661149f2313866a221a7b
      f585351a92f85104bff7c284233c338b10eb1df7
      9bc730a19041f9ec7cb33c626e811aa233efb18c
  cache:rev-branch-cache -- {} (mandatory: False)
  phase-heads -- {} (mandatory: True)
      26805aba1e600a82e93661149f2313866a221a7b draft
  $ hg strip --no-backup C
  $ hg unbundle -q bundle
  $ rm bundle
  $ hg log -G -T '{desc} {phase}\n'
  o  E secret
  |
  o  D secret
  |
  o  C draft
  |
  o  B draft
  |
  o  A public
  
Root revision's phase is preserved
  $ hg bundle -a bundle
  5 changesets found
  $ hg strip --no-backup A
  $ hg unbundle -q bundle
  $ rm bundle
  $ hg log -G -T '{desc} {phase}\n'
  o  E secret
  |
  o  D secret
  |
  o  C draft
  |
  o  B draft
  |
  o  A public
  
Completely public history can be restored
  $ hg phase --public E
  $ hg bundle -a bundle
  5 changesets found
  $ hg strip --no-backup A
  $ hg unbundle -q bundle
  $ rm bundle
  $ hg log -G -T '{desc} {phase}\n'
  o  E public
  |
  o  D public
  |
  o  C public
  |
  o  B public
  |
  o  A public
  
Direct transition from public to secret can be restored
  $ hg phase --secret --force D
  $ hg bundle -a bundle
  5 changesets found
  $ hg strip --no-backup A
  $ hg unbundle -q bundle
  $ rm bundle
  $ hg log -G -T '{desc} {phase}\n'
  o  E secret
  |
  o  D secret
  |
  o  C public
  |
  o  B public
  |
  o  A public
  
Revisions within bundle preserve their phase even if parent changes its phase
  $ hg phase --draft --force B
  $ hg bundle --base B -r E bundle
  3 changesets found
  $ hg strip --no-backup C
  $ hg phase --public B
  $ hg unbundle -q bundle
  $ rm bundle
  $ hg log -G -T '{desc} {phase}\n'
  o  E secret
  |
  o  D secret
  |
  o  C draft
  |
  o  B public
  |
  o  A public
  
Phase of ancestors of stripped node get advanced to accommodate child
  $ hg bundle --base B -r E bundle
  3 changesets found
  $ hg strip --no-backup C
  $ hg phase --force --secret B
  $ hg unbundle -q bundle
  $ rm bundle
  $ hg log -G -T '{desc} {phase}\n'
  o  E secret
  |
  o  D secret
  |
  o  C draft
  |
  o  B draft
  |
  o  A public
  
Unbundling advances phases of changesets even if they were already in the repo.
To test that, create a bundle of everything in draft phase and then unbundle
to see that secret becomes draft, but public remains public.
  $ hg phase --draft --force A
  $ hg phase --draft E
  $ hg bundle -a bundle
  5 changesets found
  $ hg phase --public A
  $ hg phase --secret --force E
  $ hg unbundle -q bundle
  $ rm bundle
  $ hg log -G -T '{desc} {phase}\n'
  o  E draft
  |
  o  D draft
  |
  o  C draft
  |
  o  B draft
  |
  o  A public
  
Unbundling change in the middle of a stack does not affect later changes
  $ hg strip --no-backup E
  $ hg phase --secret --force D
  $ hg log -G -T '{desc} {phase}\n'
  o  D secret
  |
  o  C draft
  |
  o  B draft
  |
  o  A public
  
  $ hg bundle --base A -r B bundle
  1 changesets found
  $ hg unbundle -q bundle
  $ rm bundle
  $ hg log -G -T '{desc} {phase}\n'
  o  D secret
  |
  o  C draft
  |
  o  B draft
  |
  o  A public
  

  $ cd ..

Set up repo with non-linear history
  $ hg init non-linear
  $ cd non-linear
  $ hg debugdrawdag <<'EOF'
  > D E
  > |\|
  > B C
  > |/
  > A
  > EOF
  $ hg phase --public C
  $ hg phase --force --secret B
  $ hg log -G -T '{node|short} {desc} {phase}\n'
  o  03ca77807e91 E draft
  |
  | o  4e4f9194f9f1 D secret
  |/|
  o |  dc0947a82db8 C public
  | |
  | o  112478962961 B secret
  |/
  o  426bada5c675 A public
  

Restore bundle of entire repo
  $ hg bundle -a bundle
  5 changesets found
  $ hg debugbundle bundle
  Stream params: {Compression: BZ}
  changegroup -- {nbchanges: 5, targetphase: 2, version: 02} (mandatory: True)
      426bada5c67598ca65036d57d9e4b64b0c1ce7a0
      112478962961147124edd43549aedd1a335e44bf
      dc0947a82db884575bb76ea10ac97b08536bfa03
      4e4f9194f9f181c57f62e823e8bdfa46ab9e4ff4
      03ca77807e919db8807c3749086dc36fb478cac0
  cache:rev-branch-cache -- {} (mandatory: False)
  phase-heads -- {} (mandatory: True)
      dc0947a82db884575bb76ea10ac97b08536bfa03 public
      03ca77807e919db8807c3749086dc36fb478cac0 draft
  $ hg strip --no-backup A
  $ hg unbundle -q bundle
  $ rm bundle
  $ hg log -G -T '{node|short} {desc} {phase}\n'
  o  03ca77807e91 E draft
  |
  | o  4e4f9194f9f1 D secret
  |/|
  o |  dc0947a82db8 C public
  | |
  | o  112478962961 B secret
  |/
  o  426bada5c675 A public
  

  $ hg bundle --base 'A + C' -r D bundle
  2 changesets found
  $ hg debugbundle bundle
  Stream params: {Compression: BZ}
  changegroup -- {nbchanges: 2, targetphase: 2, version: 02} (mandatory: True)
      112478962961147124edd43549aedd1a335e44bf
      4e4f9194f9f181c57f62e823e8bdfa46ab9e4ff4
  cache:rev-branch-cache -- {} (mandatory: False)
  phase-heads -- {} (mandatory: True)
  $ rm bundle

  $ hg bundle --base A -r D bundle
  3 changesets found
  $ hg debugbundle bundle
  Stream params: {Compression: BZ}
  changegroup -- {nbchanges: 3, targetphase: 2, version: 02} (mandatory: True)
      112478962961147124edd43549aedd1a335e44bf
      dc0947a82db884575bb76ea10ac97b08536bfa03
      4e4f9194f9f181c57f62e823e8bdfa46ab9e4ff4
  cache:rev-branch-cache -- {} (mandatory: False)
  phase-heads -- {} (mandatory: True)
      dc0947a82db884575bb76ea10ac97b08536bfa03 public
  $ rm bundle

  $ hg bundle --base 'B + C' -r 'D + E' bundle
  2 changesets found
  $ hg debugbundle bundle
  Stream params: {Compression: BZ}
  changegroup -- {nbchanges: 2, targetphase: 2, version: 02} (mandatory: True)
      4e4f9194f9f181c57f62e823e8bdfa46ab9e4ff4
      03ca77807e919db8807c3749086dc36fb478cac0
  cache:rev-branch-cache -- {} (mandatory: False)
  phase-heads -- {} (mandatory: True)
      03ca77807e919db8807c3749086dc36fb478cac0 draft
  $ rm bundle