view tests/test-rebase-dest.t @ 34179:036d47d7cf39

copytrace: move fast heuristic copytracing algorithm to core

copytrace extension in fb-hgext has a heuristic implementation of copy tracing
which is faster than the current copy tracing. The heuristic limits the search
of copies to just files that are either:

1) Renames in the same directory
2) Moved to other directory with same name

The default copytrace implementation is very slow as it finds all the new files
that were added from merge base up to the head commit and for each file it
checks whether it this was copied or moved version of a different file.

Stash@fb did analysis for the above heuristics on the fb repo and found that
among 2,443,768 moves/copies there are only 32,234 moves/copies which does not
fall under the above heuristics which is approx. 0.013 of total copies.

This patch moves the heuristics algorithm under config
`experimental.copytrace=heuristics`.

While moving fbext to core, this patch removes couple of less useful config
options named `sourcecommitlimit` and `maxmovescandidatestocheck`.

Tests are also added for the heuristics algorithm, which are basically copied
from fbext/tests/test-copytrace.t. The tests follow a pattern creating a server
repo and then cloning to a local repo to create public and draft changesets, the
distinction which will be useful in upcoming patches.

After this patch `experimental.copytrace` has the following behaviour:

1) `off`: turns off copytracing
2) `heuristics`: use the heuristic algorithm added in this patch.
3) everything else: use the full copytracing algorithm

.. feature::

   A new fast heuristic algorithm for copytracing which assumes that the files
   moves are either::
   1) Renames in the same directory
   2) Moves in other directories with same names
   You can use this algorithm by setting `experimental.copytrace=heuristics`.

Differential Revision: https://phab.mercurial-scm.org/D623

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 (glob)
  $ 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 (glob)
  $ 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 (glob)

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 (glob)

  $ 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('map')
  > def map(repo, subset, x):
  >     """(set, mapping)"""
  >     setarg, maparg = revsetlang.getargs(x, 2, 2, '')
  >     rset = revset.getset(repo, smartset.fullreposet(repo), setarg)
  >     mapstr = revsetlang.getstring(maparg, '')
  >     map = dict(a.split(':') for a in mapstr.split(','))
  >     rev = rset.first()
  >     desc = repo[rev].description()
  >     newdesc = map.get(desc)
  >     if newdesc == 'null':
  >         revs = [-1]
  >     else:
  >         query = revsetlang.formatspec('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}: {desc} {instabilities}" -r 'sort(all(), topo)'
  > [extensions]
  > maprevset=$TESTTMP/maprevset.py
  > [experimental]
  > rebase.multidest=true
  > stabilization=all
  > 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+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: D
  
  o  2: C
  |
  | o  1: B
  |
  o  0: 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]

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: F
  |
  o  8: E
  |
  | o  7: C
  | |
  | o  6: B
  | |
  | o  1: D
  |
  o  0: 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: C
  |\
  | o    7: B
  | |\
  o | |  5: G
  | | |
  | | o  4: E
  | | |
  o | |  2: F
   / /
  | o  1: D
  |
  o  0: A
  
Move to a previous parent:

  $ rebasewithdag -s E+F+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: H
  |
  | o  5: D
  |/
  o  3: C
  |
  | o  9: G
  |/
  o  1: B
  |
  | o  8: F
  |/
  | o  2: E
  |/
  o  0: 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: B
  |
  o  4: C
  |
  o  3: D
  |
  o  0: 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: F
  |
  o  3: D
  |
  | o    4: E
  | |\
  +---o  2: C
  | |
  | o  1: B
  |/
  o  0: 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: F
  |
  o  20: G
  |
  o  19: K
  |
  o  18: D
  |
  o  17: E
  |
  o  16: B
  |
  o  15: J
  |
  o  14: C
  |
  o  13: H
  |
  o  12: A
  |
  o  11: 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
  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: G
  |
  o  21: F2
  |
  o  20: E3
  |
  o  19: D
  |
  o  18: C
  |
  o  17: J
  |
  o  15: I2
  |
  o  12: H
  |
  o  5: B2
  |
  o  4: N
  |
  o  2: M
  |
  o  0: A