view tests/test-rebase-obsolete3.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

==========================
Test rebase with obsolete
==========================

Enable obsolete

  $ cat >> $HGRCPATH << EOF
  > [command-templates]
  > log= {rev}:{node|short} {desc|firstline}{if(obsolete,' ({obsfate})')}
  > [experimental]
  > evolution.createmarkers=True
  > evolution.allowunstable=True
  > [phases]
  > publish=False
  > [extensions]
  > rebase=
  > drawdag=$TESTDIR/drawdag.py
  > strip=
  > EOF

Divergence cases due to obsolete changesets
-------------------------------------------

We should ignore branches with unstable changesets when they are based on an
obsolete changeset which successor is in rebase set.

  $ hg init divergence
  $ cd divergence
  $ cat >> .hg/hgrc << EOF
  > [extensions]
  > strip =
  > [alias]
  > strip = strip --no-backup --quiet
  > [templates]
  > instabilities = '{rev}:{node|short} {desc|firstline}{if(instabilities," ({instabilities})")}\n'
  > EOF

  $ hg debugdrawdag <<EOF
  >   e   f
  >   |   |
  >   d'  d # replace: d -> d'
  >    \ /
  >     c
  >     |
  >   x b
  >    \|
  >     a
  > EOF
  1 new orphan changesets
  $ hg log -G -r 'a'::
  *  7:1143e9adc121 f
  |
  | o  6:d60ebfa0f1cb e
  | |
  | o  5:027ad6c5830d d'
  | |
  x |  4:76be324c128b d (rewritten using replace as 5:027ad6c5830d)
  |/
  o  3:a82ac2b38757 c
  |
  | o  2:630d7c95eff7 x
  | |
  o |  1:488e1b7e7341 b
  |/
  o  0:b173517d0057 a
  

Changeset d and its descendants are excluded to avoid divergence of d, which
would occur because the successor of d (d') is also in rebaseset. As a
consequence f (descendant of d) is left behind.

  $ hg rebase -b 'e' -d 'x'
  rebasing 1:488e1b7e7341 b "b"
  rebasing 3:a82ac2b38757 c "c"
  note: not rebasing 4:76be324c128b d "d" and its descendants as this would cause divergence
  rebasing 5:027ad6c5830d d' "d'"
  rebasing 6:d60ebfa0f1cb e "e"
  $ hg log -G -r 'a'::
  o  11:eb6d63fc4ed5 e
  |
  o  10:44d8c724a70c d'
  |
  o  9:d008e6b4d3fd c
  |
  o  8:67e8f4a16c49 b
  |
  | *  7:1143e9adc121 f
  | |
  | | x  6:d60ebfa0f1cb e (rewritten using rebase as 11:eb6d63fc4ed5)
  | | |
  | | x  5:027ad6c5830d d' (rewritten using rebase as 10:44d8c724a70c)
  | | |
  | x |  4:76be324c128b d (rewritten using replace as 5:027ad6c5830d)
  | |/
  | x  3:a82ac2b38757 c (rewritten using rebase as 9:d008e6b4d3fd)
  | |
  o |  2:630d7c95eff7 x
  | |
  | x  1:488e1b7e7341 b (rewritten using rebase as 8:67e8f4a16c49)
  |/
  o  0:b173517d0057 a
  
  $ hg strip -r 8:
  $ hg log -G -r 'a'::
  *  7:1143e9adc121 f
  |
  | o  6:d60ebfa0f1cb e
  | |
  | o  5:027ad6c5830d d'
  | |
  x |  4:76be324c128b d (rewritten using replace as 5:027ad6c5830d)
  |/
  o  3:a82ac2b38757 c
  |
  | o  2:630d7c95eff7 x
  | |
  o |  1:488e1b7e7341 b
  |/
  o  0:b173517d0057 a
  

If the rebase set has an obsolete (d) with a successor (d') outside the rebase
set and none in destination, we still get the divergence warning.
By allowing divergence, we can perform the rebase.

  $ hg rebase -r 'c'::'f' -d 'x'
  abort: this rebase will cause divergences from: 76be324c128b
  (to force the rebase please set experimental.evolution.allowdivergence=True)
  [20]
  $ hg rebase --config experimental.evolution.allowdivergence=true -r 'c'::'f' -d 'x'
  rebasing 3:a82ac2b38757 c "c"
  rebasing 4:76be324c128b d "d"
  rebasing 7:1143e9adc121 f tip "f"
  1 new orphan changesets
  2 new content-divergent changesets
  $ hg log -G -r 'a':: -T instabilities
  o  10:e1744ea07510 f
  |
  *  9:e2b36ea9a0a0 d (content-divergent)
  |
  o  8:6a0376de376e c
  |
  | x  7:1143e9adc121 f
  | |
  | | *  6:d60ebfa0f1cb e (orphan)
  | | |
  | | *  5:027ad6c5830d d' (orphan content-divergent)
  | | |
  | x |  4:76be324c128b d
  | |/
  | x  3:a82ac2b38757 c
  | |
  o |  2:630d7c95eff7 x
  | |
  | o  1:488e1b7e7341 b
  |/
  o  0:b173517d0057 a
  
  $ hg strip -r 8:

(Not skipping obsoletes means that divergence is allowed.)

  $ hg rebase --config experimental.rebaseskipobsolete=false -r 'c'::'f' -d 'x'
  rebasing 3:a82ac2b38757 c "c"
  rebasing 4:76be324c128b d "d"
  rebasing 7:1143e9adc121 f tip "f"
  1 new orphan changesets
  2 new content-divergent changesets

  $ hg strip -r 0:

Similar test on a more complex graph

  $ hg debugdrawdag <<EOF
  >       g
  >       |
  >   f   e
  >   |   |
  >   e'  d # replace: e -> e'
  >    \ /
  >     c
  >     |
  >   x b
  >    \|
  >     a
  > EOF
  1 new orphan changesets
  $ hg log -G -r 'a':
  *  8:2876ce66c6eb g
  |
  | o  7:3ffec603ab53 f
  | |
  x |  6:e36fae928aec e (rewritten using replace as 5:63324dc512ea)
  | |
  | o  5:63324dc512ea e'
  | |
  o |  4:76be324c128b d
  |/
  o  3:a82ac2b38757 c
  |
  | o  2:630d7c95eff7 x
  | |
  o |  1:488e1b7e7341 b
  |/
  o  0:b173517d0057 a
  
  $ hg rebase -b 'f' -d 'x'
  rebasing 1:488e1b7e7341 b "b"
  rebasing 3:a82ac2b38757 c "c"
  rebasing 4:76be324c128b d "d"
  note: not rebasing 6:e36fae928aec e "e" and its descendants as this would cause divergence
  rebasing 5:63324dc512ea e' "e'"
  rebasing 7:3ffec603ab53 f "f"
  $ hg log -G -r 'a':
  o  13:ef6251596616 f
  |
  o  12:b6f172e64af9 e'
  |
  | o  11:a1707a5b7c2c d
  |/
  o  10:d008e6b4d3fd c
  |
  o  9:67e8f4a16c49 b
  |
  | *  8:2876ce66c6eb g
  | |
  | | x  7:3ffec603ab53 f (rewritten using rebase as 13:ef6251596616)
  | | |
  | x |  6:e36fae928aec e (rewritten using replace as 5:63324dc512ea)
  | | |
  | | x  5:63324dc512ea e' (rewritten using rebase as 12:b6f172e64af9)
  | | |
  | x |  4:76be324c128b d (rewritten using rebase as 11:a1707a5b7c2c)
  | |/
  | x  3:a82ac2b38757 c (rewritten using rebase as 10:d008e6b4d3fd)
  | |
  o |  2:630d7c95eff7 x
  | |
  | x  1:488e1b7e7341 b (rewritten using rebase as 9:67e8f4a16c49)
  |/
  o  0:b173517d0057 a
  

issue5782
  $ hg strip -r 0:
  $ hg debugdrawdag <<EOF
  >       d
  >       |
  >   c1  c # replace: c -> c1
  >    \ /
  >     b
  >     |
  >     a
  > EOF
  1 new orphan changesets
  $ hg debugobsolete `hg log -T "{node}" --hidden -r 'desc("c1")'`
  1 new obsolescence markers
  obsoleted 1 changesets
  $ hg log -G -r 'a': --hidden
  *  4:76be324c128b d
  |
  | x  3:ef8a456de8fa c1 (pruned)
  | |
  x |  2:a82ac2b38757 c (rewritten using replace as 3:ef8a456de8fa)
  |/
  o  1:488e1b7e7341 b
  |
  o  0:b173517d0057 a
  
  $ hg rebase -d 0 -r 2
  note: not rebasing 2:a82ac2b38757 c "c", it has no successor
  $ hg log -G -r 'a': --hidden
  *  4:76be324c128b d
  |
  | x  3:ef8a456de8fa c1 (pruned)
  | |
  x |  2:a82ac2b38757 c (rewritten using replace as 3:ef8a456de8fa)
  |/
  o  1:488e1b7e7341 b
  |
  o  0:b173517d0057 a
  
  $ cd ..

Start a normal rebase. When it runs into conflicts, rewrite one of the
commits in the rebase set, causing divergence when the rebase continues.

  $ hg init $TESTTMP/new-divergence-after-conflict
  $ cd $TESTTMP/new-divergence-after-conflict
  $ hg debugdrawdag <<'EOS'
  >  C2
  >  | C1
  >  |/
  >  B # B/D=B
  >  | D
  >  |/
  >  A
  > EOS
  $ hg rebase -r B::C1 -d D
  rebasing 1:2ec65233581b B "B"
  merging D
  warning: conflicts while merging D! (edit, then use 'hg resolve --mark')
  unresolved conflicts (see 'hg resolve', then 'hg rebase --continue')
  [240]
  $ hg debugobsolete $(hg log -r C1 -T '{node}') $(hg log -r C2 -T '{node}')
  1 new obsolescence markers
  obsoleted 1 changesets
  $ hg log -G
  o  4:fdb9df6b130c C2
  |
  | x  3:7e5bfd3c08f0 C1 (rewritten as 4:fdb9df6b130c)
  |/
  | @  2:b18e25de2cf5 D
  | |
  % |  1:2ec65233581b B
  |/
  o  0:426bada5c675 A
  
  $ echo resolved > D
  $ hg resolve -m D
  (no more unresolved files)
  continue: hg rebase --continue
  $ hg rebase -c
  rebasing 1:2ec65233581b B "B"
  note: not rebasing 3:7e5bfd3c08f0 C1 "C1" and its descendants as this would cause divergence
  1 new orphan changesets

Rebase merge where successor of one parent is equal to destination (issue5198)

  $ hg init p1-succ-is-dest
  $ cd p1-succ-is-dest

  $ hg debugdrawdag <<EOF
  >   F
  >  /|
  > E D B # replace: D -> B
  >  \|/
  >   A
  > EOF
  1 new orphan changesets

  $ hg rebase -d B -s D
  note: not rebasing 2:b18e25de2cf5 D "D", already in destination as 1:112478962961 B "B"
  rebasing 4:66f1a38021c9 F tip "F"
  $ hg log -G
  o    5:50e9d60b99c6 F
  |\
  | | x  4:66f1a38021c9 F (rewritten using rebase as 5:50e9d60b99c6)
  | |/|
  | o |  3:7fb047a69f22 E
  | | |
  | | x  2:b18e25de2cf5 D (rewritten using replace as 1:112478962961)
  | |/
  o |  1:112478962961 B
  |/
  o  0:426bada5c675 A
  
  $ cd ..

Rebase merge where successor of other parent is equal to destination

  $ hg init p2-succ-is-dest
  $ cd p2-succ-is-dest

  $ hg debugdrawdag <<EOF
  >   F
  >  /|
  > E D B # replace: E -> B
  >  \|/
  >   A
  > EOF
  1 new orphan changesets

  $ hg rebase -d B -s E
  note: not rebasing 3:7fb047a69f22 E "E", already in destination as 1:112478962961 B "B"
  rebasing 4:66f1a38021c9 F tip "F"
  $ hg log -G
  o    5:aae1787dacee F
  |\
  | | x  4:66f1a38021c9 F (rewritten using rebase as 5:aae1787dacee)
  | |/|
  | | x  3:7fb047a69f22 E (rewritten using replace as 1:112478962961)
  | | |
  | o |  2:b18e25de2cf5 D
  | |/
  o /  1:112478962961 B
  |/
  o  0:426bada5c675 A
  
  $ cd ..

Rebase merge where successor of one parent is ancestor of destination

  $ hg init p1-succ-in-dest
  $ cd p1-succ-in-dest

  $ hg debugdrawdag <<EOF
  >   F C
  >  /| |
  > E D B # replace: D -> B
  >  \|/
  >   A
  > EOF
  1 new orphan changesets

  $ hg rebase -d C -s D
  note: not rebasing 2:b18e25de2cf5 D "D", already in destination as 1:112478962961 B "B"
  rebasing 5:66f1a38021c9 F tip "F"

  $ hg log -G
  o    6:0913febf6439 F
  |\
  +---x  5:66f1a38021c9 F (rewritten using rebase as 6:0913febf6439)
  | | |
  | o |  4:26805aba1e60 C
  | | |
  o | |  3:7fb047a69f22 E
  | | |
  +---x  2:b18e25de2cf5 D (rewritten using replace as 1:112478962961)
  | |
  | o  1:112478962961 B
  |/
  o  0:426bada5c675 A
  
  $ cd ..

Rebase merge where successor of other parent is ancestor of destination

  $ hg init p2-succ-in-dest
  $ cd p2-succ-in-dest

  $ hg debugdrawdag <<EOF
  >   F C
  >  /| |
  > E D B # replace: E -> B
  >  \|/
  >   A
  > EOF
  1 new orphan changesets

  $ hg rebase -d C -s E
  note: not rebasing 3:7fb047a69f22 E "E", already in destination as 1:112478962961 B "B"
  rebasing 5:66f1a38021c9 F tip "F"
  $ hg log -G
  o    6:c6ab0cc6d220 F
  |\
  +---x  5:66f1a38021c9 F (rewritten using rebase as 6:c6ab0cc6d220)
  | | |
  | o |  4:26805aba1e60 C
  | | |
  | | x  3:7fb047a69f22 E (rewritten using replace as 1:112478962961)
  | | |
  o---+  2:b18e25de2cf5 D
   / /
  o /  1:112478962961 B
  |/
  o  0:426bada5c675 A
  
  $ cd ..

Rebase merge where successor of one parent is ancestor of destination

  $ hg init p1-succ-in-dest-b
  $ cd p1-succ-in-dest-b

  $ hg debugdrawdag <<EOF
  >   F C
  >  /| |
  > E D B # replace: E -> B
  >  \|/
  >   A
  > EOF
  1 new orphan changesets

  $ hg rebase -d C -b F
  rebasing 2:b18e25de2cf5 D "D"
  note: not rebasing 3:7fb047a69f22 E "E", already in destination as 1:112478962961 B "B"
  rebasing 5:66f1a38021c9 F tip "F"
  note: not rebasing 5:66f1a38021c9 F tip "F", its destination already has all its changes
  $ hg log -G
  o  6:8f47515dda15 D
  |
  | x    5:66f1a38021c9 F (pruned using rebase)
  | |\
  o | |  4:26805aba1e60 C
  | | |
  | | x  3:7fb047a69f22 E (rewritten using replace as 1:112478962961)
  | | |
  | x |  2:b18e25de2cf5 D (rewritten using rebase as 6:8f47515dda15)
  | |/
  o /  1:112478962961 B
  |/
  o  0:426bada5c675 A
  
  $ cd ..

Rebase merge where successor of other parent is ancestor of destination

  $ hg init p2-succ-in-dest-b
  $ cd p2-succ-in-dest-b

  $ hg debugdrawdag <<EOF
  >   F C
  >  /| |
  > E D B # replace: D -> B
  >  \|/
  >   A
  > EOF
  1 new orphan changesets

  $ hg rebase -d C -b F
  note: not rebasing 2:b18e25de2cf5 D "D", already in destination as 1:112478962961 B "B"
  rebasing 3:7fb047a69f22 E "E"
  rebasing 5:66f1a38021c9 F tip "F"
  note: not rebasing 5:66f1a38021c9 F tip "F", its destination already has all its changes

  $ hg log -G
  o  6:533690786a86 E
  |
  | x    5:66f1a38021c9 F (pruned using rebase)
  | |\
  o | |  4:26805aba1e60 C
  | | |
  | | x  3:7fb047a69f22 E (rewritten using rebase as 6:533690786a86)
  | | |
  | x |  2:b18e25de2cf5 D (rewritten using replace as 1:112478962961)
  | |/
  o /  1:112478962961 B
  |/
  o  0:426bada5c675 A
  
  $ cd ..

Rebase merge where extinct node has successor that is not an ancestor of
destination

  $ hg init extinct-with-succ-not-in-dest
  $ cd extinct-with-succ-not-in-dest

  $ hg debugdrawdag <<EOF
  > E C # replace: C -> E
  > | |
  > D B
  > |/
  > A
  > EOF

  $ hg rebase -d D -s B
  rebasing 1:112478962961 B "B"
  note: not rebasing 3:26805aba1e60 C "C" and its descendants as this would cause divergence

  $ cd ..

  $ hg init p2-succ-in-dest-c
  $ cd p2-succ-in-dest-c

The scenario here was that B::D were developed on default.  B was queued on
stable, but amended before being push to hg-committed.  C was queued on default,
along with unrelated J.

  $ hg debugdrawdag <<EOF
  > J
  > |
  > F
  > |
  > E
  > | D
  > | |
  > | C      # replace: C -> F
  > | |  H I # replace: B -> H -> I
  > | B  |/
  > |/   G
  > A
  > EOF
  1 new orphan changesets

This strip seems to be the key to avoid an early divergence warning.
  $ hg --config extensions.strip= --hidden strip -qr H
  1 new orphan changesets

  $ hg rebase -b 'desc("D")' -d 'desc("J")'
  abort: this rebase will cause divergences from: 112478962961
  (to force the rebase please set experimental.evolution.allowdivergence=True)
  [20]

Rebase merge where both parents have successors in destination

  $ hg init p12-succ-in-dest
  $ cd p12-succ-in-dest
  $ hg debugdrawdag <<'EOS'
  >   E   F
  >  /|  /|  # replace: A -> C
  > A B C D  # replace: B -> D
  > | |
  > X Y
  > EOS
  1 new orphan changesets
  $ hg rebase -r A+B+E -d F
  note: not rebasing 4:a3d17304151f A "A", already in destination as 0:96cc3511f894 C "C"
  note: not rebasing 5:b23a2cc00842 B "B", already in destination as 1:058c1e1fb10a D "D"
  rebasing 7:dac5d11c5a7d E tip "E"
  abort: rebasing 7:dac5d11c5a7d will include unwanted changes from 3:59c792af609c, 5:b23a2cc00842 or 2:ba2b7fa7166d, 4:a3d17304151f
  [10]
  $ cd ..

Rebase a non-clean merge. One parent has successor in destination, the other
parent moves as requested.

  $ hg init p1-succ-p2-move
  $ cd p1-succ-p2-move
  $ hg debugdrawdag <<'EOS'
  >   D Z
  >  /| | # replace: A -> C
  > A B C # D/D = D
  > EOS
  1 new orphan changesets
  $ hg rebase -r A+B+D -d Z
  note: not rebasing 0:426bada5c675 A "A", already in destination as 2:96cc3511f894 C "C"
  rebasing 1:fc2b737bb2e5 B "B"
  rebasing 3:b8ed089c80ad D "D"

  $ rm .hg/localtags
  $ hg log -G
  o  6:e4f78693cc88 D
  |
  o  5:76840d832e98 B
  |
  o  4:50e41c1f3950 Z
  |
  o  2:96cc3511f894 C
  
  $ hg files -r tip
  B
  C
  D
  Z

  $ cd ..

  $ hg init p1-move-p2-succ
  $ cd p1-move-p2-succ
  $ hg debugdrawdag <<'EOS'
  >   D Z
  >  /| |  # replace: B -> C
  > A B C  # D/D = D
  > EOS
  1 new orphan changesets
  $ hg rebase -r B+A+D -d Z
  rebasing 0:426bada5c675 A "A"
  note: not rebasing 1:fc2b737bb2e5 B "B", already in destination as 2:96cc3511f894 C "C"
  rebasing 3:b8ed089c80ad D "D"

  $ rm .hg/localtags
  $ hg log -G
  o  6:1b355ed94d82 D
  |
  o  5:a81a74d764a6 A
  |
  o  4:50e41c1f3950 Z
  |
  o  2:96cc3511f894 C
  
  $ hg files -r tip
  A
  C
  D
  Z

  $ cd ..