view tests/test-rebase-dest.t @ 45121:b6269741ed42

config: add option to control creation of empty successors during rewrite

The default for many history-rewriting commands (e.g. rebase and absorb) is
that changesets which would become empty are not created in the target branch.
This makes sense if the source branch consists of small fix-up changes. For
more advanced workflows that make heavy use of history-editing to create
curated patch series, dropping empty changesets is not as important or even
undesirable.

Some users want to keep the meta-history, e.g. to make finding comments in a
code review tool easier or to avoid that divergent bookmarks are created. For
that, obsmarkers from the (to-be) empty changeset to the changeset(s) that
already made the changes should be added. If a to-be empty changeset is pruned
without a successor, adding the obsmarkers is hard because the changeset has to
be found within the hidden part of the history.

If rebasing in TortoiseHg, it’s easy to miss the fact that the to-be empty
changeset was pruned. An empty changeset will function as a reminder that
obsmarkers should be added.

Martin von Zweigbergk mentioned another advantage. Stripping the successor will
de-obsolete the predecessor. If no (empty) successor is created, this won’t be
possible.

In the future, we may want to consider other behaviors, like e.g. creating the
empty successor, but pruning it right away. Therefore this configuration
accepts 'skip' and 'keep' instead of being a boolean configuration.

Require a destination
  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > rebase =
  > [commands]
  > rebase.requiredest = True
  > EOF
  $ hg init repo
  $ cd repo
  $ echo a >> a
  $ hg commit -qAm aa
  $ echo b >> b
  $ hg commit -qAm bb
  $ hg up ".^"
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo c >> c
  $ hg commit -qAm cc
  $ hg rebase
  abort: you must specify a destination
  (use: hg rebase -d REV)
  [255]
  $ hg rebase -d 1
  rebasing 2:5db65b93a12b "cc" (tip)
  saved backup bundle to $TESTTMP/repo/.hg/strip-backup/5db65b93a12b-4fb789ec-rebase.hg
  $ hg rebase -d 0 -r . -q
  $ HGPLAIN=1 hg rebase
  rebasing 2:889b0bc6a730 "cc" (tip)
  saved backup bundle to $TESTTMP/repo/.hg/strip-backup/889b0bc6a730-41ec4f81-rebase.hg
  $ hg rebase -d 0 -r . -q
  $ hg --config commands.rebase.requiredest=False rebase
  rebasing 2:279de9495438 "cc" (tip)
  saved backup bundle to $TESTTMP/repo/.hg/strip-backup/279de9495438-ab0a5128-rebase.hg

Requiring dest should not break continue or other rebase options
  $ hg up 1 -q
  $ echo d >> c
  $ hg commit -qAm dc
  $ hg log -G -T '{rev} {desc}'
  @  3 dc
  |
  | o  2 cc
  |/
  o  1 bb
  |
  o  0 aa
  
  $ hg rebase -d 2
  rebasing 3:0537f6b50def "dc" (tip)
  merging c
  warning: conflicts while merging c! (edit, then use 'hg resolve --mark')
  unresolved conflicts (see hg resolve, then hg rebase --continue)
  [1]
  $ echo d > c
  $ hg resolve --mark --all
  (no more unresolved files)
  continue: hg rebase --continue
  $ hg rebase --continue
  rebasing 3:0537f6b50def "dc" (tip)
  saved backup bundle to $TESTTMP/repo/.hg/strip-backup/0537f6b50def-be4c7386-rebase.hg

  $ cd ..

Check rebase.requiredest interaction with pull --rebase
  $ hg clone repo clone
  updating to branch default
  3 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd repo
  $ echo e > e
  $ hg commit -qAm ee
  $ cd ..
  $ cd clone
  $ echo f > f
  $ hg commit -qAm ff
  $ hg pull --rebase
  abort: rebase destination required by configuration
  (use hg pull followed by hg rebase -d DEST)
  [255]

Setup rebase with multiple destinations

  $ cd $TESTTMP

  $ cat >> $TESTTMP/maprevset.py <<EOF
  > from __future__ import absolute_import
  > from mercurial import registrar, revset, revsetlang, smartset
  > revsetpredicate = registrar.revsetpredicate()
  > cache = {}
  > @revsetpredicate(b'map')
  > def map(repo, subset, x):
  >     """(set, mapping)"""
  >     setarg, maparg = revsetlang.getargs(x, 2, 2, b'')
  >     rset = revset.getset(repo, smartset.fullreposet(repo), setarg)
  >     mapstr = revsetlang.getstring(maparg, b'')
  >     map = dict(a.split(b':') for a in mapstr.split(b','))
  >     rev = rset.first()
  >     desc = repo[rev].description()
  >     newdesc = map.get(desc)
  >     if newdesc == b'null':
  >         revs = [-1]
  >     else:
  >         query = revsetlang.formatspec(b'desc(%s)', newdesc)
  >         revs = repo.revs(query)
  >     return smartset.baseset(revs)
  > EOF

  $ cat >> $HGRCPATH <<EOF
  > [ui]
  > allowemptycommit=1
  > [extensions]
  > drawdag=$TESTDIR/drawdag.py
  > [phases]
  > publish=False
  > [alias]
  > tglog = log -G --template "{rev}: {node|short} {desc} {instabilities}" -r 'sort(all(), topo)'
  > [extensions]
  > maprevset=$TESTTMP/maprevset.py
  > [experimental]
  > evolution=true
  > EOF

  $ rebasewithdag() {
  >   N=`"$PYTHON" -c "print($N+1)"`
  >   hg init repo$N && cd repo$N
  >   hg debugdrawdag
  >   hg rebase "$@" > _rebasetmp
  >   r=$?
  >   grep -v 'saved backup bundle' _rebasetmp
  >   [ $r -eq 0 ] && rm -f .hg/localtags && hg tglog
  >   cd ..
  >   return $r
  > }

Destination resolves to an empty set:

  $ rebasewithdag -s B -d 'SRC - SRC' <<'EOS'
  > C
  > |
  > B
  > |
  > A
  > EOS
  nothing to rebase - empty destination
  [1]

Multiple destinations and --collapse are not compatible:

  $ rebasewithdag -s C+E -d 'SRC^^' --collapse <<'EOS'
  > C F
  > | |
  > B E
  > | |
  > A D
  > EOS
  abort: --collapse does not work with multiple destinations
  [255]

Multiple destinations cannot be used with --base:

  $ rebasewithdag -b B -b E -d 'SRC^^' --collapse <<'EOS'
  > B E
  > | |
  > A D
  > EOS
  abort: unknown revision 'SRC'!
  [255]

Rebase to null should work:

  $ rebasewithdag -r A+C+D -d 'null' <<'EOS'
  > C D
  > | |
  > A B
  > EOS
  already rebased 0:426bada5c675 "A" (A)
  already rebased 2:dc0947a82db8 "C" (C)
  rebasing 3:004dc1679908 "D" (D tip)
  o  4: d8d8601abd5e D
  
  o  2: dc0947a82db8 C
  |
  | o  1: fc2b737bb2e5 B
  |
  o  0: 426bada5c675 A
  
Destination resolves to multiple changesets:

  $ rebasewithdag -s B -d 'ALLSRC+SRC' <<'EOS'
  > C
  > |
  > B
  > |
  > Z
  > EOS
  abort: rebase destination for f0a671a46792 is not unique
  [255]

Destination is an ancestor of source:

  $ rebasewithdag -s B -d 'SRC' <<'EOS'
  > C
  > |
  > B
  > |
  > Z
  > EOS
  abort: source and destination form a cycle
  [255]

BUG: cycles aren't flagged correctly when --dry-run is set:
  $ rebasewithdag -s B -d 'SRC' --dry-run <<'EOS'
  > C
  > |
  > B
  > |
  > Z
  > EOS
  abort: source and destination form a cycle
  starting dry-run rebase; repository will not be changed
  [255]

Switch roots:

  $ rebasewithdag -s 'all() - roots(all())' -d 'roots(all()) - ::SRC' <<'EOS'
  > C  F
  > |  |
  > B  E
  > |  |
  > A  D
  > EOS
  rebasing 2:112478962961 "B" (B)
  rebasing 4:26805aba1e60 "C" (C)
  rebasing 3:cd488e83d208 "E" (E)
  rebasing 5:0069ba24938a "F" (F tip)
  o  9: d150ff263fc8 F
  |
  o  8: 66f30a1a2eab E
  |
  | o  7: 93db94ffae0e C
  | |
  | o  6: d0071c3b0c88 B
  | |
  | o  1: 058c1e1fb10a D
  |
  o  0: 426bada5c675 A
  
Different destinations for merge changesets with a same root:

  $ rebasewithdag -s B -d '((parents(SRC)-B-A)::) - (::ALLSRC)' <<'EOS'
  > C G
  > |\|
  > | F
  > |
  > B E
  > |\|
  > A D
  > EOS
  rebasing 3:a4256619d830 "B" (B)
  rebasing 6:8e139e245220 "C" (C tip)
  o    8: d7d1169e9b1c C
  |\
  | o    7: 2ed0c8546285 B
  | |\
  o | |  5: 8fdb2c1feb20 G
  | | |
  | | o  4: cd488e83d208 E
  | | |
  o | |  2: a6661b868de9 F
   / /
  | o  1: 058c1e1fb10a D
  |
  o  0: 426bada5c675 A
  
Move to a previous parent:

  $ rebasewithdag -s E -s F -s G -d 'SRC^^' <<'EOS'
  >     H
  >     |
  >   D G
  >   |/
  >   C F
  >   |/
  >   B E  # E will be ignored, since E^^ is empty
  >   |/
  >   A
  > EOS
  rebasing 4:33441538d4aa "F" (F)
  rebasing 6:cf43ad9da869 "G" (G)
  rebasing 7:eef94f3b5f03 "H" (H tip)
  o  10: b3d84c6666cf H
  |
  | o  5: f585351a92f8 D
  |/
  o  3: 26805aba1e60 C
  |
  | o  9: f7c28a1a15e2 G
  |/
  o  1: 112478962961 B
  |
  | o  8: 02aa697facf7 F
  |/
  | o  2: 7fb047a69f22 E
  |/
  o  0: 426bada5c675 A
  
Source overlaps with destination:

  $ rebasewithdag -s 'B+C+D' -d 'map(SRC, "B:C,C:D")' <<'EOS'
  > B C D
  >  \|/
  >   A
  > EOS
  rebasing 2:dc0947a82db8 "C" (C)
  rebasing 1:112478962961 "B" (B)
  o  5: 5fe9935d5222 B
  |
  o  4: 12d20731b9e0 C
  |
  o  3: b18e25de2cf5 D
  |
  o  0: 426bada5c675 A
  
Detect cycles early:

  $ rebasewithdag -r 'all()-Z' -d 'map(SRC, "A:B,B:C,C:D,D:B")' <<'EOS'
  > A B C
  >  \|/
  >   | D
  >   |/
  >   Z
  > EOS
  abort: source and destination form a cycle
  [255]

Detect source is ancestor of dest in runtime:

  $ rebasewithdag -r 'C+B' -d 'map(SRC, "C:B,B:D")' -q <<'EOS'
  >   D
  >   |
  > B C
  >  \|
  >   A
  > EOS
  abort: source is ancestor of destination
  [255]

"Already rebased" fast path still works:

  $ rebasewithdag -r 'all()' -d 'SRC^' <<'EOS'
  >   E F
  >  /| |
  > B C D
  >  \|/
  >   A
  > EOS
  already rebased 1:112478962961 "B" (B)
  already rebased 2:dc0947a82db8 "C" (C)
  already rebased 3:b18e25de2cf5 "D" (D)
  already rebased 4:312782b8f06e "E" (E)
  already rebased 5:ad6717a6a58e "F" (F tip)
  o  5: ad6717a6a58e F
  |
  o  3: b18e25de2cf5 D
  |
  | o    4: 312782b8f06e E
  | |\
  +---o  2: dc0947a82db8 C
  | |
  | o  1: 112478962961 B
  |/
  o  0: 426bada5c675 A
  
Massively rewrite the DAG:

  $ rebasewithdag -r 'all()' -d 'map(SRC, "A:I,I:null,H:A,B:J,J:C,C:H,D:E,F:G,G:K,K:D,E:B")' <<'EOS'
  > D G K
  > | | |
  > C F J
  > | | |
  > B E I
  >  \| |
  >   A H
  > EOS
  rebasing 4:701514e1408d "I" (I)
  rebasing 0:426bada5c675 "A" (A)
  rebasing 1:e7050b6e5048 "H" (H)
  rebasing 5:26805aba1e60 "C" (C)
  rebasing 7:cf89f86b485b "J" (J)
  rebasing 2:112478962961 "B" (B)
  rebasing 3:7fb047a69f22 "E" (E)
  rebasing 8:f585351a92f8 "D" (D)
  rebasing 10:ae41898d7875 "K" (K tip)
  rebasing 9:711f53bbef0b "G" (G)
  rebasing 6:64a8289d2492 "F" (F)
  o  21: 3735afb3713a F
  |
  o  20: 07698142d7a7 G
  |
  o  19: 33aba52e7e72 K
  |
  o  18: 9fdae89dc5a1 D
  |
  o  17: 277dda9a65ee E
  |
  o  16: 9c74fd8657ad B
  |
  o  15: 6527eb0688bb J
  |
  o  14: e94d655b928d C
  |
  o  13: 620d6d349459 H
  |
  o  12: a569a116758f A
  |
  o  11: 2bf1302f5c18 I
  
Resolve instability:

  $ rebasewithdag <<'EOF' -r 'orphan()-obsolete()' -d 'max((successors(max(roots(ALLSRC) & ::SRC)^)-obsolete())::)'
  >      F2
  >      |
  >    J E E2
  >    | |/
  > I2 I | E3
  >   \| |/
  >    H | G
  >    | | |
  >   B2 D F
  >    | |/         # rebase: B -> B2
  >    N C          # amend: E -> E2
  >    | |          # amend: E2 -> E3
  >    M B          # rebase: F -> F2
  >     \|          # amend: I -> I2
  >      A
  > EOF
  6 new orphan changesets
  rebasing 16:5c432343bf59 "J" (J tip)
  rebasing 3:26805aba1e60 "C" (C)
  rebasing 6:f585351a92f8 "D" (D)
  rebasing 10:ffebc37c5d0b "E3" (E3)
  rebasing 13:fb184bcfeee8 "F2" (F2)
  rebasing 11:dc838ab4c0da "G" (G)
  o  22: 174f63d574a8 G
  |
  o  21: c9d9fbe76705 F2
  |
  o  20: 0a03c2ede755 E3
  |
  o  19: 228d9d2541b1 D
  |
  o  18: cd856b400c95 C
  |
  o  17: 9148200c858c J
  |
  o  15: eb74780f5094 I2
  |
  o  12: 78309edd643f H
  |
  o  5: 4b4531bd8e1d B2
  |
  o  4: 337c285c272b N
  |
  o  2: 699bc4b6fa22 M
  |
  o  0: 426bada5c675 A