view tests/test-obsolete.t @ 3573:d53277cdc1e7

evolve: handle stabilization of merge changeset with both parents obsoleted

This patch adds logic to stabilize an orphan merge changeset having both parents
obsoleted.

The logic tries to first stabilize the merge changeset on successor of second
parent and then stabilize the new changeset formed on the successor of first
parent. We are stabilizing on second parent first and then to second parent to
preserve the first parent's successor as first parent of the merge changeset.

Conflicts can occcur and we can loose processing information, therefore we store
a variable in statefile `orphanmerge` which represents whether we are processing
a merge changeset with both parents obsoleted.

Thanks to Pierre-Yves David for suggesting this way and helping to understand
the correctness of this.

More rigourous test cases for this will be added in next patch.

  $ . $TESTDIR/testlib/common.sh
  $ cat >> $HGRCPATH <<EOF
  > [web]
  > push_ssl = false
  > allow_push = *
  > [phases]
  > publish=False
  > [alias]
  > debugobsolete=debugobsolete -d '0 0'
  > [extensions]
  > hgext.rebase=
  > EOF
  $ echo "evolve=$(echo $(dirname $TESTDIR))/hgext3rd/evolve/" >> $HGRCPATH
  $ mkcommit() {
  >    echo "$1" > "$1"
  >    hg add "$1"
  >    hg ci -m "add $1"
  > }
  $ alias qlog="hg log --template='{rev}\n- {node|short}\n'"
  $ hg init local
  $ cd local
  $ mkcommit a # 0
  $ hg phase -p .
  $ mkcommit b # 1
  $ mkcommit c # 2
  $ hg up 1
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ mkcommit obsol_c # 3
  created new head
  $ getid 2
  4538525df7e2b9f09423636c61ef63a4cb872a2d
  $ getid 3
  0d3f46688ccc6e756c7e96cf64c391c411309597
  $ hg debugobsolete 4538525df7e2b9f09423636c61ef63a4cb872a2d 0d3f46688ccc6e756c7e96cf64c391c411309597
  obsoleted 1 changesets
  $ hg debugobsolete
  4538525df7e2b9f09423636c61ef63a4cb872a2d 0d3f46688ccc6e756c7e96cf64c391c411309597 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}


Test hidden() revset

  $ qlog -r 'hidden()' --hidden
  2
  - 4538525df7e2

Test that obsolete changeset are hidden

  $ qlog
  3
  - 0d3f46688ccc
  1
  - 7c3bad9141dc
  0
  - 1f0dee641bb7
  $ qlog --hidden
  3
  - 0d3f46688ccc
  2
  - 4538525df7e2
  1
  - 7c3bad9141dc
  0
  - 1f0dee641bb7
  $ qlog -r 'obsolete()' --hidden
  2
  - 4538525df7e2

Test that obsolete precursors are properly computed

  $ qlog -r 'precursors(.)' --hidden
  2
  - 4538525df7e2
  $ qlog -r .
  3
  - 0d3f46688ccc
  $ hg odiff
  diff -r 4538525df7e2 -r 0d3f46688ccc c
  --- a/c	Thu Jan 01 00:00:00 1970 +0000
  +++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
  @@ -1,1 +0,0 @@
  -c
  diff -r 4538525df7e2 -r 0d3f46688ccc obsol_c
  --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
  +++ b/obsol_c	Thu Jan 01 00:00:00 1970 +0000
  @@ -0,0 +1,1 @@
  +obsol_c

Test that obsolete successors are properly computed

  $ qlog -r 'successors(2)' --hidden
  3
  - 0d3f46688ccc

test obsolete changeset with non-obsolete descendant
  $ hg up 1 -q
  $ mkcommit "obsol_c'" # 4 (on 1)
  created new head
  $ hg debugobsolete `getid 3` `getid 4`
  obsoleted 1 changesets
  $ qlog
  4
  - 725c380fe99b
  1
  - 7c3bad9141dc
  0
  - 1f0dee641bb7
  $ qlog -r 'obsolete()' --hidden
  2
  - 4538525df7e2
  3
  - 0d3f46688ccc
  $ qlog -r 'allprecursors(4)' --hidden
  2
  - 4538525df7e2
  3
  - 0d3f46688ccc
  $ qlog -r 'allsuccessors(2)' --hidden
  3
  - 0d3f46688ccc
  4
  - 725c380fe99b
  $ hg up --hidden 3 -q
  updating to a hidden changeset 0d3f46688ccc
  (hidden revision '0d3f46688ccc' was rewritten as: 725c380fe99b)
  working directory parent is obsolete! (0d3f46688ccc)
(reported by parents too)
  $ hg parents
  changeset:   3:0d3f46688ccc
  parent:      1:7c3bad9141dc
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  obsolete:    rewritten as 4:725c380fe99b
  summary:     add obsol_c
  
  working directory parent is obsolete! (0d3f46688ccc)
  (use 'hg evolve' to update to its successor: 725c380fe99b)
  $ mkcommit d # 5 (on 3)
  1 new orphan changesets
  $ qlog -r 'obsolete()'
  3
  - 0d3f46688ccc

  $ qlog -r 'extinct()' --hidden
  2
  - 4538525df7e2
  $ qlog -r 'suspended()'
  3
  - 0d3f46688ccc
  $ qlog -r "orphan()"
  5
  - a7a6f2b5d8a5

Test obsolete keyword

  $ hg --hidden log -G \
  >  --template '{rev}:{node|short}@{branch}({separate("/", obsolete, phase)}) {desc|firstline}\n'
  @  5:a7a6f2b5d8a5@default(draft) add d
  |
  | o  4:725c380fe99b@default(draft) add obsol_c'
  | |
  x |  3:0d3f46688ccc@default(obsolete/draft) add obsol_c
  |/
  | x  2:4538525df7e2@default(obsolete/draft) add c
  |/
  o  1:7c3bad9141dc@default(draft) add b
  |
  o  0:1f0dee641bb7@default(public) add a
  

Test communication of obsolete relation with a compatible client

  $ hg init ../other-new
  $ hg phase --draft 'secret() - extinct()' # until we fix exclusion
  abort: empty revision set
  [255]
  $ hg push ../other-new
  pushing to ../other-new
  searching for changes
  abort: push includes orphan changeset: a7a6f2b5d8a5!
  (use 'hg evolve' to get a stable history or --force to ignore warnings)
  [255]
  $ hg push -f ../other-new
  pushing to ../other-new
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 5 changesets with 5 changes to 5 files (+1 heads)
  2 new obsolescence markers
  1 new orphan changesets
  $ hg -R ../other-new verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  5 files, 5 changesets, 5 total revisions
  $ qlog -R ../other-new -r 'obsolete()'
  2
  - 0d3f46688ccc
  $ qlog -R ../other-new
  4
  - a7a6f2b5d8a5
  3
  - 725c380fe99b
  2
  - 0d3f46688ccc
  1
  - 7c3bad9141dc
  0
  - 1f0dee641bb7
  $ hg up --hidden 3 -q
  working directory parent is obsolete! (0d3f46688ccc)
  $ mkcommit obsol_d # 6
  1 new orphan changesets
  created new head
  $ hg debugobsolete `getid 5` `getid 6`
  obsoleted 1 changesets
  $ qlog
  6
  - 95de7fc6918d
  4
  - 725c380fe99b
  3
  - 0d3f46688ccc
  1
  - 7c3bad9141dc
  0
  - 1f0dee641bb7
  $ qlog -r 'obsolete()'
  3
  - 0d3f46688ccc
  $ hg push ../other-new
  pushing to ../other-new
  searching for changes
  abort: push includes orphan changeset: 95de7fc6918d!
  (use 'hg evolve' to get a stable history or --force to ignore warnings)
  [255]
  $ hg push ../other-new -f # use f because there is unstability
  pushing to ../other-new
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files (+1 heads)
  1 new obsolescence markers
  obsoleted 1 changesets
  $ qlog -R ../other-new
  5
  - 95de7fc6918d
  3
  - 725c380fe99b
  2
  - 0d3f46688ccc
  1
  - 7c3bad9141dc
  0
  - 1f0dee641bb7
  $ qlog -R ../other-new -r 'obsolete()'
  2
  - 0d3f46688ccc

Pushing again does not advertise extinct changesets

  $ hg push ../other-new
  pushing to ../other-new
  searching for changes
  no changes found
  [1]

  $ hg up --hidden -q .^ # 3
  working directory parent is obsolete! (0d3f46688ccc)
  $ mkcommit "obsol_d'" # 7
  1 new orphan changesets
  created new head
  $ hg debugobsolete `getid 6` `getid 7`
  obsoleted 1 changesets
  $ hg pull -R ../other-new .
  pulling from .
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to [12] files \(\+1 heads\) (re)
  1 new obsolescence markers
  obsoleted 1 changesets
  new changesets 909a0fb57e5d
  (run 'hg heads' to see heads, 'hg merge' to merge)
  $ qlog -R ../other-new
  6
  - 909a0fb57e5d
  3
  - 725c380fe99b
  2
  - 0d3f46688ccc
  1
  - 7c3bad9141dc
  0
  - 1f0dee641bb7

pushing to stuff that doesn't support obsolescence

DISABLED. the _enable switch is global :-/

..  $ hg init ../other-old
..  > # XXX I don't like this but changeset get published otherwise
..  > # remove it when we will get a --keep-state flag for push
..  $ echo '[extensions]'  > ../other-old/.hg/hgrc
..  $ echo "obsolete=!$(echo $(dirname $TESTDIR))/obsolete.py" >> ../other-old/.hg/hgrc
..  $ hg push ../other-old
..  pushing to ../other-old
..  searching for changes
..  abort: push includes an unstable changeset: 909a0fb57e5d!
..  (use 'hg evolve' to get a stable history or --force to ignore warnings)
..  [255]
..  $ hg push -f ../other-old
..  pushing to ../other-old
..  searching for changes
..  adding changesets
..  adding manifests
..  adding file changes
..  added 5 changesets with 5 changes to 5 files (+1 heads)
..  $ qlog -R ../other-ol
..  4
..  - 909a0fb57e5d
..  3
..  - 725c380fe99b
..  2
..  - 0d3f46688ccc
..  1
..  - 7c3bad9141dc
..  0
..  - 1f0dee641bb7

clone support

  $ hg clone . ../cloned
  > # The warning should go away once we have default value to set ready before we pull
  updating to branch default
  4 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ qlog -R ../cloned --hidden
  7
  - 909a0fb57e5d
  6
  - 95de7fc6918d
  5
  - a7a6f2b5d8a5
  4
  - 725c380fe99b
  3
  - 0d3f46688ccc
  2
  - 4538525df7e2
  1
  - 7c3bad9141dc
  0
  - 1f0dee641bb7

Test rollback support

  $ hg up --hidden .^ -q # 3
  working directory parent is obsolete! (0d3f46688ccc)
  $ mkcommit "obsol_d''"
  1 new orphan changesets
  created new head
  $ hg debugobsolete `getid 7` `getid 8`
  obsoleted 1 changesets
  $ cd ../other-new
  $ hg up -q 3
  $ hg pull ../local/
  pulling from ../local/
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to [12] files \(\+1 heads\) (re)
  1 new obsolescence markers
  obsoleted 1 changesets
  new changesets 159dfc9fa5d3
  (run 'hg heads' to see heads, 'hg merge' to merge)

  $ hg up -q 7 # to check rollback update behavior
  $ qlog
  7
  - 159dfc9fa5d3
  3
  - 725c380fe99b
  2
  - 0d3f46688ccc
  1
  - 7c3bad9141dc
  0
  - 1f0dee641bb7
  $ hg rollback
  repository tip rolled back to revision 6 (undo pull)
  working directory now based on revision 3
  $ hg summary
  parent: 3:725c380fe99b 
   add obsol_c'
  branch: default
  commit: 1 deleted, 2 unknown (clean)
  update: 2 new changesets, 2 branch heads (merge)
  phases: 4 draft
  orphan: 1 changesets
  $ qlog
  6
  - 909a0fb57e5d
  3
  - 725c380fe99b
  2
  - 0d3f46688ccc
  1
  - 7c3bad9141dc
  0
  - 1f0dee641bb7
  $ cd ../local

obsolete public changeset

# move draft boundary from 0 to 1
  $ sed -e 's/1f0dee641bb7258c56bd60e93edfa2405381c41e/7c3bad9141dcb46ff89abf5f61856facd56e476c/' -i'.back' .hg/store/phaseroots

  $ hg up null
  0 files updated, 0 files merged, 4 files removed, 0 files unresolved
  $ mkcommit toto # 9
  created new head
  $ hg id -n
  9
  $ hg debugobsolete `getid 0` `getid 9`
  1 new phase-divergent changesets
83b5778897ad try to obsolete immutable changeset 1f0dee641bb7
# at core level the warning is not issued
# this is now a big issue now that we have bumped warning
  $ qlog -r 'obsolete()'
  3
  - 0d3f46688ccc
allow to just kill changeset

  $ qlog
  9
  - 83b5778897ad
  8
  - 159dfc9fa5d3
  4
  - 725c380fe99b
  3
  - 0d3f46688ccc
  1
  - 7c3bad9141dc
  0
  - 1f0dee641bb7

  $ hg debugobsolete `getid 9` #kill
  obsoleted 1 changesets
  $ hg up null -q # to be not based on 9 anymore
  $ qlog
  8
  - 159dfc9fa5d3
  4
  - 725c380fe99b
  3
  - 0d3f46688ccc
  1
  - 7c3bad9141dc
  0
  - 1f0dee641bb7

Check that auto update ignores hidden changeset
  $ hg up 0
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg up 
  3 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to "159dfc9fa5d3: add obsol_d''"
  1 other heads for branch "default"
  $ hg id -n
  8

Check that named update does too

  $ hg update default
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg id -n
  8

  $ hg up null -q # to be not based on 9 anymore

check rebase compat

  $ hg log -G  --template='{rev} - {node|short} {desc}\n'
  *  8 - 159dfc9fa5d3 add obsol_d''
  |
  | o  4 - 725c380fe99b add obsol_c'
  | |
  x |  3 - 0d3f46688ccc add obsol_c
  |/
  o  1 - 7c3bad9141dc add b
  |
  o  0 - 1f0dee641bb7 add a
  

  $ hg log -G  --template='{rev} - {node|short} {desc}\n' --hidden
  x  9 - 83b5778897ad add toto
  
  *  8 - 159dfc9fa5d3 add obsol_d''
  |
  | x  7 - 909a0fb57e5d add obsol_d'
  |/
  | x  6 - 95de7fc6918d add obsol_d
  |/
  | x  5 - a7a6f2b5d8a5 add d
  |/
  | o  4 - 725c380fe99b add obsol_c'
  | |
  x |  3 - 0d3f46688ccc add obsol_c
  |/
  | x  2 - 4538525df7e2 add c
  |/
  o  1 - 7c3bad9141dc add b
  |
  o  0 - 1f0dee641bb7 add a
  

should not rebase extinct changesets

#excluded 'whole rebase set is extinct and ignored.' message not in core
  $ hg rebase -b '3' -d 4 --traceback --config experimental.rebaseskipobsolete=0
  rebasing 3:0d3f46688ccc "add obsol_c"
  rebasing 8:159dfc9fa5d3 "add obsol_d''"
  2 new content-divergent changesets
  $ hg --hidden log -q -r 'successors(3)'
  4:725c380fe99b
  10:2033b4e49474
  $ hg up tip
  ? files updated, 0 files merged, 0 files removed, 0 files unresolved (glob)
  $ hg log -G --template='{rev} - {node|short} {desc}\n'
  @  11 - 9468a5f5d8b2 add obsol_d''
  |
  *  10 - 2033b4e49474 add obsol_c
  |
  *  4 - 725c380fe99b add obsol_c'
  |
  o  1 - 7c3bad9141dc add b
  |
  o  0 - 1f0dee641bb7 add a
  

Does not complain about new head if you obsolete the old one
(re necessary when we start running discovery on unfiltered repo in core)

  $ hg push ../other-new --traceback
  pushing to ../other-new
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 1 changes to [12] files (re)
  3 new obsolescence markers
  obsoleted 1 changesets
  2 new content-divergent changesets
  $ hg up -q 10
  $ mkcommit "obsol_d'''"
  created new head
  $ hg debugobsolete `getid 11` `getid 12`
  obsoleted 1 changesets
  $ hg push ../other-new --traceback
  pushing to ../other-new
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files (+1 heads)
  1 new obsolescence markers
  obsoleted 1 changesets
  $ cd ..

check bumped detection
(make an obsolete changeset public)

  $ cd local
  $ hg phase --hidden --public 11
  1 new phase-divergent changesets
  $ hg log -G --template='{rev} - ({phase}) {node|short} {desc}\n'
  @  12 - (draft) 6db5e282cb91 add obsol_d'''
  |
  | o  11 - (public) 9468a5f5d8b2 add obsol_d''
  |/
  o  10 - (public) 2033b4e49474 add obsol_c
  |
  o  4 - (public) 725c380fe99b add obsol_c'
  |
  o  1 - (public) 7c3bad9141dc add b
  |
  o  0 - (public) 1f0dee641bb7 add a
  
  $ hg log -r 'phasedivergent()'
  changeset:   12:6db5e282cb91
  tag:         tip
  parent:      10:2033b4e49474
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  instability: phase-divergent
  summary:     add obsol_d'''
  
  $ hg push ../other-new/
  pushing to ../other-new/
  searching for changes
  abort: push includes phase-divergent changeset: 6db5e282cb91!
  (use 'hg evolve' to get a stable history or --force to ignore warnings)
  [255]

Check hg commit --amend compat

  $ hg up 'desc(obsol_c)'
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ mkcommit f
  created new head
  $ echo 42 >> f
  $ hg commit --amend --traceback --quiet
  $ hg log -G
  @  changeset:   14:705ab2a6b72e
  |  tag:         tip
  |  parent:      10:2033b4e49474
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     add f
  |
  | *  changeset:   12:6db5e282cb91
  |/   parent:      10:2033b4e49474
  |    user:        test
  |    date:        Thu Jan 01 00:00:00 1970 +0000
  |    instability: phase-divergent
  |    summary:     add obsol_d'''
  |
  | o  changeset:   11:9468a5f5d8b2
  |/   user:        test
  |    date:        Thu Jan 01 00:00:00 1970 +0000
  |    summary:     add obsol_d''
  |
  o  changeset:   10:2033b4e49474
  |  parent:      4:725c380fe99b
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     add obsol_c
  |
  o  changeset:   4:725c380fe99b
  |  parent:      1:7c3bad9141dc
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     add obsol_c'
  |
  o  changeset:   1:7c3bad9141dc
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     add b
  |
  o  changeset:   0:1f0dee641bb7
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     add a
  
  $ hg debugobsolete | grep -v 33d458d86621f3186c40bfccd77652f4a122743e
  4538525df7e2b9f09423636c61ef63a4cb872a2d 0d3f46688ccc6e756c7e96cf64c391c411309597 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  0d3f46688ccc6e756c7e96cf64c391c411309597 725c380fe99b5e76613493f0903e8d11ddc70d54 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  a7a6f2b5d8a54b81bc7aa2fba2934ad6d700a79e 95de7fc6918dea4c9c8d5382f50649794b474c4a 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  95de7fc6918dea4c9c8d5382f50649794b474c4a 909a0fb57e5d909f353d89e394ffd7e0890fec88 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  909a0fb57e5d909f353d89e394ffd7e0890fec88 159dfc9fa5d334d7e03a0aecfc7f7ab4c3431fea 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  1f0dee641bb7258c56bd60e93edfa2405381c41e 83b5778897adafb967ef2f75be3aaa4fce49a4cc 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  83b5778897adafb967ef2f75be3aaa4fce49a4cc 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  0d3f46688ccc6e756c7e96cf64c391c411309597 2033b4e494742365851fac84d276640cbf52833e 0 (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '4', 'operation': 'rebase', 'user': 'test'}
  159dfc9fa5d334d7e03a0aecfc7f7ab4c3431fea 9468a5f5d8b2c5d91e17474e95ae4791e9718fdf 0 (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '4', 'operation': 'rebase', 'user': 'test'}
  9468a5f5d8b2c5d91e17474e95ae4791e9718fdf 6db5e282cb91df5c43ff1f1287c119ff83230d42 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  0b1b6dd009c037985363e2290a0b579819f659db 705ab2a6b72e2cd86edb799ebe15f2695f86143e 0 (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '8', 'operation': 'amend', 'user': 'test'}
#no produced by 2.3
33d458d86621f3186c40bfccd77652f4a122743e 3734a65252e69ddcced85901647a4f335d40de1e 0 {'date': '* *', 'user': 'test'} (glob)

Check divergence detection (note: multiple successors is sorted by changeset hash)

  $ hg up 9468a5f5d8b2 #  add obsol_d''
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ mkcommit "obsolet_conflicting_d"
  $ hg summary
  parent: 15:50f11e5e3a63 tip
   add obsolet_conflicting_d
  branch: default
  commit: (clean)
  update: (2|9|11) new changesets, (3|9|10) branch heads \(merge\) (re)
  phases: 3 draft
  phase-divergent: 1 changesets
  $ hg debugobsolete `getid a7a6f2b5d8a5` `getid 50f11e5e3a63`
  2 new content-divergent changesets
  $ hg log -r 'contentdivergent()'
  changeset:   12:6db5e282cb91
  parent:      10:2033b4e49474
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  instability: phase-divergent, content-divergent
  summary:     add obsol_d'''
  
  changeset:   15:50f11e5e3a63
  tag:         tip
  parent:      11:9468a5f5d8b2
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  instability: content-divergent
  summary:     add obsolet_conflicting_d
  

  $ hg up --hidden 3 -q
  updating to a hidden changeset 0d3f46688ccc
  (hidden revision '0d3f46688ccc' has diverged)
  working directory parent is obsolete! (0d3f46688ccc)
  $ hg evolve
  parent is obsolete with multiple successors:
  [4] add obsol_c'
  [10] add obsol_c
  [2]
  $ hg olog
  @  0d3f46688ccc (3) add obsol_c
  |    rewritten(parent) as 2033b4e49474 using rebase by test (Thu Jan 01 00:00:00 1970 +0000)
  |    rewritten as 725c380fe99b by test (Thu Jan 01 00:00:00 1970 +0000)
  |
  x  4538525df7e2 (2) add c
       rewritten as 0d3f46688ccc by test (Thu Jan 01 00:00:00 1970 +0000)
  

Check import reports new unstable changeset:

  $ hg up --hidden 2
  updating to a hidden changeset 4538525df7e2
  (hidden revision '4538525df7e2' has diverged)
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  working directory parent is obsolete! (4538525df7e2)
  (4538525df7e2 has diverged, use 'hg evolve --list --content-divergent' to resolve the issue)
  $ hg export 9468a5f5d8b2 | hg import -
  applying patch from stdin
  1 new orphan changesets


Relevant marker computation
==============================

  $ hg log -G --hidden
  @  changeset:   16:a5f7a21fe7bc
  |  tag:         tip
  |  parent:      2:4538525df7e2
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  instability: orphan
  |  summary:     add obsol_d''
  |
  | *  changeset:   15:50f11e5e3a63
  | |  parent:      11:9468a5f5d8b2
  | |  user:        test
  | |  date:        Thu Jan 01 00:00:00 1970 +0000
  | |  instability: content-divergent
  | |  summary:     add obsolet_conflicting_d
  | |
  | | o  changeset:   14:705ab2a6b72e
  | | |  parent:      10:2033b4e49474
  | | |  user:        test
  | | |  date:        Thu Jan 01 00:00:00 1970 +0000
  | | |  summary:     add f
  | | |
  | | | x  changeset:   13:0b1b6dd009c0
  | | |/   parent:      10:2033b4e49474
  | | |    user:        test
  | | |    date:        Thu Jan 01 00:00:00 1970 +0000
  | | |    obsolete:    amended using amend as 14:705ab2a6b72e
  | | |    summary:     add f
  | | |
  | | | *  changeset:   12:6db5e282cb91
  | | |/   parent:      10:2033b4e49474
  | | |    user:        test
  | | |    date:        Thu Jan 01 00:00:00 1970 +0000
  | | |    instability: phase-divergent, content-divergent
  | | |    summary:     add obsol_d'''
  | | |
  | o |  changeset:   11:9468a5f5d8b2
  | |/   user:        test
  | |    date:        Thu Jan 01 00:00:00 1970 +0000
  | |    summary:     add obsol_d''
  | |
  | o  changeset:   10:2033b4e49474
  | |  parent:      4:725c380fe99b
  | |  user:        test
  | |  date:        Thu Jan 01 00:00:00 1970 +0000
  | |  summary:     add obsol_c
  | |
  | | x  changeset:   9:83b5778897ad
  | |    parent:      -1:000000000000
  | |    user:        test
  | |    date:        Thu Jan 01 00:00:00 1970 +0000
  | |    obsolete:    pruned
  | |    summary:     add toto
  | |
  | | x  changeset:   8:159dfc9fa5d3
  | | |  parent:      3:0d3f46688ccc
  | | |  user:        test
  | | |  date:        Thu Jan 01 00:00:00 1970 +0000
  | | |  obsolete:    rebased using rebase as 11:9468a5f5d8b2
  | | |  summary:     add obsol_d''
  | | |
  | | | x  changeset:   7:909a0fb57e5d
  | | |/   parent:      3:0d3f46688ccc
  | | |    user:        test
  | | |    date:        Thu Jan 01 00:00:00 1970 +0000
  | | |    obsolete:    rewritten as 8:159dfc9fa5d3
  | | |    summary:     add obsol_d'
  | | |
  | | | x  changeset:   6:95de7fc6918d
  | | |/   parent:      3:0d3f46688ccc
  | | |    user:        test
  | | |    date:        Thu Jan 01 00:00:00 1970 +0000
  | | |    obsolete:    rewritten as 7:909a0fb57e5d
  | | |    summary:     add obsol_d
  | | |
  | | | x  changeset:   5:a7a6f2b5d8a5
  | | |/   parent:      3:0d3f46688ccc
  | | |    user:        test
  | | |    date:        Thu Jan 01 00:00:00 1970 +0000
  | | |    obsolete:    rewritten as 6:95de7fc6918d
  | | |    obsolete:    rewritten as 15:50f11e5e3a63
  | | |    summary:     add d
  | | |
  | o |  changeset:   4:725c380fe99b
  | | |  parent:      1:7c3bad9141dc
  | | |  user:        test
  | | |  date:        Thu Jan 01 00:00:00 1970 +0000
  | | |  summary:     add obsol_c'
  | | |
  | | x  changeset:   3:0d3f46688ccc
  | |/   parent:      1:7c3bad9141dc
  | |    user:        test
  | |    date:        Thu Jan 01 00:00:00 1970 +0000
  | |    obsolete:    rewritten as 4:725c380fe99b
  | |    obsolete:    rebased using rebase as 10:2033b4e49474
  | |    summary:     add obsol_c
  | |
  x |  changeset:   2:4538525df7e2
  |/   user:        test
  |    date:        Thu Jan 01 00:00:00 1970 +0000
  |    obsolete:    rewritten as 3:0d3f46688ccc
  |    summary:     add c
  |
  o  changeset:   1:7c3bad9141dc
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     add b
  |
  o  changeset:   0:1f0dee641bb7
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     add a
  

Simple rewrite

  $ hg  --hidden debugobsolete --rev 3
  4538525df7e2b9f09423636c61ef63a4cb872a2d 0d3f46688ccc6e756c7e96cf64c391c411309597 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}

simple rewrite with a prune attached to it

  $ hg debugobsolete --rev 15
  a7a6f2b5d8a54b81bc7aa2fba2934ad6d700a79e 50f11e5e3a63806e678c734e525502f522d37e38 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}

Transitive rewrite

  $ hg --hidden debugobsolete --rev 8
  909a0fb57e5d909f353d89e394ffd7e0890fec88 159dfc9fa5d334d7e03a0aecfc7f7ab4c3431fea 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  95de7fc6918dea4c9c8d5382f50649794b474c4a 909a0fb57e5d909f353d89e394ffd7e0890fec88 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  a7a6f2b5d8a54b81bc7aa2fba2934ad6d700a79e 95de7fc6918dea4c9c8d5382f50649794b474c4a 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}