documentation: add some internals documentation about bid merge
This is an important algorithm that was only documented on the wiki so far.
Some update to the algorithm (and associated doc) is to expected in the future
since the bid merge algorithm is bug-ridden when it comes to file deletion comes
to play.
Differential Revision: https://phab.mercurial-scm.org/D8711
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