bisect: avoid copying ancestor list for non-merge commits
During a bisection, hg needs to compute a list of all ancestors for every
candidate commit. This is accomplished via a bottom-up traversal of the set of
candidates, during which each revision's ancestor list is populated using the
ancestor list of its parent(s). Previously, this involved copying the entire
list, which could be very long in if the bisection range was large.
To help improve this, we can observe that each candidate commit is visited
exactly once, at which point its ancestor list is copied into its children's
lists and then dropped. In the case of non-merge commits, a commit's ancestor
list consists exactly of its parent's list plus itself. This means that we can
trivially reuse the parent's existing list for one of its non-merge children,
which avoids copying entirely if that commit is the parent's only child. This
makes bisections over linear ranges of commits much faster.
During some informal testing in the large publicly-available `mozilla-central`
repository, this noticeably sped up bisections over large ranges of history:
Setup:
$ cd mozilla-central
$ hg bisect --reset
$ hg bisect --good 0
$ hg log -r tip -T '{rev}\n'
628417
Test:
$ time hg bisect --bad tip --noupdate
Before:
real 3m35.927s
user 3m35.553s
sys 0m0.319s
After:
real 1m41.142s
user 1m40.810s
sys 0m0.285s
$ cat >> $HGRCPATH <<EOF
> [extensions]
> rebase=
> mq=
> drawdag=$TESTDIR/drawdag.py
>
> [phases]
> publish=False
>
> [alias]
> tglog = log -G --template "{rev}: {node|short} '{desc}' {branches}\n"
> tglogp = log -G --template "{rev}: {node|short} {phase} '{desc}' {branches}\n"
> EOF
Highest phase of source commits is used:
$ hg init phase
$ cd phase
$ hg debugdrawdag << 'EOF'
> D
> |
> F C
> | |
> E B
> |/
> A
> EOF
$ hg phase --force --secret D
$ cat > $TESTTMP/editor.sh <<EOF
> echo "==== before editing"
> cat \$1
> echo "===="
> echo "edited manually" >> \$1
> EOF
$ HGEDITOR="sh $TESTTMP/editor.sh" hg rebase --collapse --keepbranches -e --source B --dest F
rebasing 1:112478962961 B "B"
rebasing 3:26805aba1e60 C "C"
rebasing 5:f585351a92f8 D tip "D"
==== before editing
Collapsed revision
* B
* C
* D
HG: Enter commit message. Lines beginning with 'HG:' are removed.
HG: Leave message empty to abort commit.
HG: --
HG: user: test
HG: branch 'default'
HG: added B
HG: added C
HG: added D
====
saved backup bundle to $TESTTMP/phase/.hg/strip-backup/112478962961-cb2a9b47-rebase.hg
$ hg tglogp
o 3: 92fa5f5fe108 secret 'Collapsed revision
| * B
| * C
| * D
|
|
| edited manually'
o 2: 64a8289d2492 draft 'F'
|
o 1: 7fb047a69f22 draft 'E'
|
o 0: 426bada5c675 draft 'A'
$ hg manifest --rev tip
A
B
C
D
E
F
$ cd ..
Merge gets linearized:
$ hg init linearized-merge
$ cd linearized-merge
$ hg debugdrawdag << 'EOF'
> F D
> |/|
> C B
> |/
> A
> EOF
$ hg phase --force --secret D
$ hg rebase --source B --collapse --dest F
rebasing 1:112478962961 B "B"
rebasing 3:4e4f9194f9f1 D "D"
saved backup bundle to $TESTTMP/linearized-merge/.hg/strip-backup/112478962961-e389075b-rebase.hg
$ hg tglog
o 3: 5bdc08b7da2b 'Collapsed revision
| * B
| * D'
o 2: afc707c82df0 'F'
|
o 1: dc0947a82db8 'C'
|
o 0: 426bada5c675 'A'
$ hg manifest --rev tip
A
B
C
F
$ cd ..
Custom message:
$ hg init message
$ cd message
$ hg debugdrawdag << 'EOF'
> C
> |
> D B
> |/
> A
> EOF
$ hg rebase --base B -m 'custom message'
abort: message can only be specified with collapse
[10]
$ cat > $TESTTMP/checkeditform.sh <<EOF
> env | grep HGEDITFORM
> true
> EOF
$ HGEDITOR="sh $TESTTMP/checkeditform.sh" hg rebase --source B --collapse -m 'custom message' -e --dest D
rebasing 1:112478962961 B "B"
rebasing 3:26805aba1e60 C tip "C"
HGEDITFORM=rebase.collapse
saved backup bundle to $TESTTMP/message/.hg/strip-backup/112478962961-f4131707-rebase.hg
$ hg tglog
o 2: 2f197b9a08f3 'custom message'
|
o 1: b18e25de2cf5 'D'
|
o 0: 426bada5c675 'A'
$ hg manifest --rev tip
A
B
C
D
$ cd ..
Rebase and collapse - more than one external (fail):
$ hg init multiple-external-parents
$ cd multiple-external-parents
$ hg debugdrawdag << 'EOF'
> G
> |\
> | F
> | |
> D E
> |\|
> H C B
> \|/
> A
> EOF
$ hg rebase -s C --dest H --collapse
abort: unable to collapse on top of 3, there is more than one external parent: 1, 6
[20]
Rebase and collapse - E onto H:
$ hg rebase -s E --dest H --collapse # root (E) is not a merge
rebasing 5:49cb92066bfd E "E"
rebasing 6:11abe3fb10b8 F "F"
rebasing 7:64e264db77f0 G tip "G"
saved backup bundle to $TESTTMP/multiple-external-parents/.hg/strip-backup/49cb92066bfd-ee8a8a79-rebase.hg
$ hg tglog
o 5: 8b2315790719 'Collapsed revision
|\ * E
| | * F
| | * G'
| o 4: 4e4f9194f9f1 'D'
| |\
o | | 3: 575c4b5ec114 'H'
| | |
+---o 2: dc0947a82db8 'C'
| |
| o 1: 112478962961 'B'
|/
o 0: 426bada5c675 'A'
$ hg manifest --rev tip
A
C
E
F
H
$ cd ..
Test that branchheads cache is updated correctly when doing a strip in which
the parent of the ancestor node to be stripped does not become a head and also,
the parent of a node that is a child of the node stripped becomes a head (node
3). The code is now much simpler and we could just test a simpler scenario
We keep it the test this way in case new complexity is injected.
Create repo b:
$ hg init branch-heads
$ cd branch-heads
$ hg debugdrawdag << 'EOF'
> G
> |\
> | F
> | |
> D E
> |\|
> H C B
> \|/
> A
> EOF
$ hg heads --template="{rev}:{node} {branch}\n"
7:64e264db77f061f16d9132b70c5a58e2461fb630 default
3:575c4b5ec114d64b681d33f8792853568bfb2b2c default
$ cat $TESTTMP/branch-heads/.hg/cache/branch2-served
64e264db77f061f16d9132b70c5a58e2461fb630 7
575c4b5ec114d64b681d33f8792853568bfb2b2c o default
64e264db77f061f16d9132b70c5a58e2461fb630 o default
$ hg strip 4
saved backup bundle to $TESTTMP/branch-heads/.hg/strip-backup/4e4f9194f9f1-5ec4b5e6-backup.hg
$ cat $TESTTMP/branch-heads/.hg/cache/branch2-served
11abe3fb10b8689b560681094b17fe161871d043 5
dc0947a82db884575bb76ea10ac97b08536bfa03 o default
575c4b5ec114d64b681d33f8792853568bfb2b2c o default
11abe3fb10b8689b560681094b17fe161871d043 o default
$ hg heads --template="{rev}:{node} {branch}\n"
5:11abe3fb10b8689b560681094b17fe161871d043 default
3:575c4b5ec114d64b681d33f8792853568bfb2b2c default
2:dc0947a82db884575bb76ea10ac97b08536bfa03 default
$ cd ..
Preserves external parent
$ hg init external-parent
$ cd external-parent
$ hg debugdrawdag << 'EOF'
> H
> |\
> | G
> | |
> | F # F/E = F\n
> | |
> D E # D/D = D\n
> |\|
> I C B
> \|/
> A
> EOF
$ hg rebase -s F --dest I --collapse # root (F) is not a merge
rebasing 6:c82b08f646f1 F "F"
file 'E' was deleted in local [dest] but was modified in other [source].
You can use (c)hanged version, leave (d)eleted, or leave (u)nresolved.
What do you want to do? u
unresolved conflicts (see 'hg resolve', then 'hg rebase --continue')
[240]
$ echo F > E
$ hg resolve -m
(no more unresolved files)
continue: hg rebase --continue
$ hg rebase -c
rebasing 6:c82b08f646f1 F "F"
rebasing 7:a6db7fa104e1 G "G"
rebasing 8:e1d201b72d91 H tip "H"
saved backup bundle to $TESTTMP/external-parent/.hg/strip-backup/c82b08f646f1-f2721fbf-rebase.hg
$ hg tglog
o 6: 681daa3e686d 'Collapsed revision
|\ * F
| | * G
| | * H'
| | o 5: 49cb92066bfd 'E'
| | |
| o | 4: 09143c0bf13e 'D'
| |\|
o | | 3: 08ebfeb61bac 'I'
| | |
| o | 2: dc0947a82db8 'C'
|/ /
| o 1: 112478962961 'B'
|/
o 0: 426bada5c675 'A'
$ hg manifest --rev tip
A
C
D
E
F
G
I
$ hg up tip -q
$ cat E
F
$ cd ..
Rebasing from multiple bases:
$ hg init multiple-bases
$ cd multiple-bases
$ hg debugdrawdag << 'EOF'
> C B
> D |/
> |/
> A
> EOF
$ hg rebase --collapse -r 'B+C' -d D
rebasing 1:fc2b737bb2e5 B "B"
rebasing 2:dc0947a82db8 C "C"
saved backup bundle to $TESTTMP/multiple-bases/.hg/strip-backup/dc0947a82db8-b0c1a7ea-rebase.hg
$ hg tglog
o 2: 2127ae44d291 'Collapsed revision
| * B
| * C'
o 1: b18e25de2cf5 'D'
|
o 0: 426bada5c675 'A'
$ cd ..
With non-contiguous commits:
$ hg init non-contiguous
$ cd non-contiguous
$ cat >> .hg/hgrc <<EOF
> [experimental]
> evolution=all
> EOF
$ hg debugdrawdag << 'EOF'
> F
> |
> E
> |
> D
> |
> C
> |
> B G
> |/
> A
> EOF
BROKEN: should be allowed
$ hg rebase --collapse -r 'B+D+F' -d G
abort: unable to collapse on top of 2, there is more than one external parent: 3, 5
[20]
$ cd ..
$ hg init multiple-external-parents-2
$ cd multiple-external-parents-2
$ hg debugdrawdag << 'EOF'
> D G
> |\ /|
> B C E F
> \| |/
> \ H /
> \|/
> A
> EOF
$ hg rebase --collapse -d H -s 'B+F'
abort: unable to collapse on top of 5, there is more than one external parent: 1, 3
[20]
$ cd ..
With internal merge:
$ hg init internal-merge
$ cd internal-merge
$ hg debugdrawdag << 'EOF'
> E
> |\
> C D
> |/
> F B
> |/
> A
> EOF
$ hg rebase -s B --collapse --dest F
rebasing 1:112478962961 B "B"
rebasing 3:26805aba1e60 C "C"
rebasing 4:be0ef73c17ad D "D"
rebasing 5:02c4367d6973 E tip "E"
saved backup bundle to $TESTTMP/internal-merge/.hg/strip-backup/112478962961-1dfb057b-rebase.hg
$ hg tglog
o 2: c0512a1797b0 'Collapsed revision
| * B
| * C
| * D
| * E'
o 1: 8908a377a434 'F'
|
o 0: 426bada5c675 'A'
$ hg manifest --rev tip
A
B
C
D
F
$ cd ..
Interactions between collapse and keepbranches
$ hg init e
$ cd e
$ echo 'a' > a
$ hg ci -Am 'A'
adding a
$ hg branch 'one'
marked working directory as branch one
(branches are permanent and global, did you want a bookmark?)
$ echo 'b' > b
$ hg ci -Am 'B'
adding b
$ hg branch 'two'
marked working directory as branch two
$ echo 'c' > c
$ hg ci -Am 'C'
adding c
$ hg up -q 0
$ echo 'd' > d
$ hg ci -Am 'D'
adding d
$ hg tglog
@ 3: 41acb9dca9eb 'D'
|
| o 2: 8ac4a08debf1 'C' two
| |
| o 1: 1ba175478953 'B' one
|/
o 0: 1994f17a630e 'A'
$ hg rebase --keepbranches --collapse -s 1 -d 3
abort: cannot collapse multiple named branches
[10]
$ cd ..
Rebase, collapse and copies
$ hg init copies
$ cd copies
$ hg unbundle "$TESTDIR/bundles/renames.hg"
adding changesets
adding manifests
adding file changes
added 4 changesets with 11 changes to 7 files (+1 heads)
new changesets f447d5abf5ea:338e84e2e558 (4 drafts)
(run 'hg heads' to see heads, 'hg merge' to merge)
$ hg up -q tip
$ hg tglog
@ 3: 338e84e2e558 'move2'
|
o 2: 6e7340ee38c0 'move1'
|
| o 1: 1352765a01d4 'change'
|/
o 0: f447d5abf5ea 'add'
$ hg rebase --collapse -d 1
rebasing 2:6e7340ee38c0 "move1"
merging a and d to d
merging b and e to e
merging c and f to f
rebasing 3:338e84e2e558 tip "move2"
merging f and c to c
merging e and g to g
saved backup bundle to $TESTTMP/copies/.hg/strip-backup/6e7340ee38c0-ef8ef003-rebase.hg
$ hg st
$ hg st --copies --change tip
A d
a
A g
b
R b
$ hg up tip -q
$ cat c
c
c
$ cat d
a
a
$ cat g
b
b
$ hg log -r . --template "{file_copies}\n"
d (a)g (b)
Test collapsing a middle revision in-place
$ hg tglog
@ 2: 64b456429f67 'Collapsed revision
| * move1
| * move2'
o 1: 1352765a01d4 'change'
|
o 0: f447d5abf5ea 'add'
$ hg rebase --collapse -r 1 -d 0
abort: cannot rebase changeset, as that will orphan 1 descendants
(see 'hg help evolution.instability')
[10]
Test collapsing in place
$ hg rebase --collapse -b . -d 0
rebasing 1:1352765a01d4 "change"
rebasing 2:64b456429f67 tip "Collapsed revision"
saved backup bundle to $TESTTMP/copies/.hg/strip-backup/1352765a01d4-45a352ea-rebase.hg
$ hg st --change tip --copies
M a
M c
A d
a
A g
b
R b
$ hg up tip -q
$ cat a
a
a
$ cat c
c
c
$ cat d
a
a
$ cat g
b
b
$ cd ..
Test stripping a revision with another child
$ hg init f
$ cd f
$ hg debugdrawdag << 'EOF'
> C B
> |/
> A
> EOF
$ hg heads --template="{rev}:{node} {branch}: {desc}\n"
2:dc0947a82db884575bb76ea10ac97b08536bfa03 default: C
1:112478962961147124edd43549aedd1a335e44bf default: B
$ hg strip C
saved backup bundle to $TESTTMP/f/.hg/strip-backup/dc0947a82db8-d21b92a4-backup.hg
$ hg tglog
o 1: 112478962961 'B'
|
o 0: 426bada5c675 'A'
$ hg heads --template="{rev}:{node} {branch}: {desc}\n"
1:112478962961147124edd43549aedd1a335e44bf default: B
$ cd ..
Test collapsing changes that add then remove a file
$ hg init collapseaddremove
$ cd collapseaddremove
$ touch base
$ hg commit -Am base
adding base
$ touch a
$ hg commit -Am a
adding a
$ hg rm a
$ touch b
$ hg commit -Am b
adding b
$ hg book foo
$ hg rebase -d 0 -r "1::2" --collapse -m collapsed
rebasing 1:6d8d9f24eec3 "a"
rebasing 2:1cc73eca5ecc foo tip "b"
saved backup bundle to $TESTTMP/collapseaddremove/.hg/strip-backup/6d8d9f24eec3-77d3b6e2-rebase.hg
$ hg log -G --template "{rev}: '{desc}' {bookmarks}"
@ 1: 'collapsed' foo
|
o 0: 'base'
$ hg manifest --rev tip
b
base
$ cd ..
Test that rebase --collapse will remember message after
running into merge conflict and invoking rebase --continue.
$ hg init collapse_remember_message
$ cd collapse_remember_message
$ hg debugdrawdag << 'EOF'
> C B # B/A = B\n
> |/ # C/A = C\n
> A
> EOF
$ hg rebase --collapse -m "new message" -b B -d C
rebasing 1:81e5401e4d37 B "B"
merging A
warning: conflicts while merging A! (edit, then use 'hg resolve --mark')
unresolved conflicts (see 'hg resolve', then 'hg rebase --continue')
[240]
$ rm A.orig
$ hg resolve --mark A
(no more unresolved files)
continue: hg rebase --continue
$ hg rebase --continue
rebasing 1:81e5401e4d37 B "B"
saved backup bundle to $TESTTMP/collapse_remember_message/.hg/strip-backup/81e5401e4d37-96c3dd30-rebase.hg
$ hg log
changeset: 2:17186933e123
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: new message
changeset: 1:043039e9df84
tag: C
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: C
changeset: 0:426bada5c675
tag: A
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: A
$ cd ..
Test aborted editor on final message
$ HGMERGE=:merge3
$ export HGMERGE
$ hg init aborted-editor
$ cd aborted-editor
$ hg debugdrawdag << 'EOF'
> C # D/A = D\n
> | # C/A = C\n
> B D # B/A = B\n
> |/ # A/A = A\n
> A
> EOF
$ hg rebase --collapse -t internal:merge3 -s B -d D
rebasing 1:f899f3910ce7 B "B"
merging A
warning: conflicts while merging A! (edit, then use 'hg resolve --mark')
unresolved conflicts (see 'hg resolve', then 'hg rebase --continue')
[240]
$ hg tglog
o 3: 63668d570d21 'C'
|
| @ 2: 82b8abf9c185 'D'
| |
% | 1: f899f3910ce7 'B'
|/
o 0: 4a2df7238c3b 'A'
$ cat A
<<<<<<< dest: 82b8abf9c185 D - test: D
D
||||||| parent of source: 4a2df7238c3b A - test: A
A
=======
B
>>>>>>> source: f899f3910ce7 B - test: B
$ echo BC > A
$ hg resolve -m
(no more unresolved files)
continue: hg rebase --continue
$ hg rebase --continue
rebasing 1:f899f3910ce7 B "B"
rebasing 3:63668d570d21 C tip "C"
merging A
warning: conflicts while merging A! (edit, then use 'hg resolve --mark')
unresolved conflicts (see 'hg resolve', then 'hg rebase --continue')
[240]
$ hg tglog
% 3: 63668d570d21 'C'
|
| @ 2: 82b8abf9c185 'D'
| |
o | 1: f899f3910ce7 'B'
|/
o 0: 4a2df7238c3b 'A'
$ cat A
<<<<<<< dest: 82b8abf9c185 D - test: D
BC
||||||| parent of source: f899f3910ce7 B - test: B
B
=======
C
>>>>>>> source: 63668d570d21 C tip - test: C
$ echo BD > A
$ hg resolve -m
(no more unresolved files)
continue: hg rebase --continue
$ HGEDITOR=false hg rebase --continue --config ui.interactive=1
already rebased 1:f899f3910ce7 B "B" as 82b8abf9c185
rebasing 3:63668d570d21 C tip "C"
abort: edit failed: false exited with status 1
[250]
$ hg tglog
o 3: 63668d570d21 'C'
|
| @ 2: 82b8abf9c185 'D'
| |
o | 1: f899f3910ce7 'B'
|/
o 0: 4a2df7238c3b 'A'
$ hg rebase --continue
already rebased 1:f899f3910ce7 B "B" as 82b8abf9c185
already rebased 3:63668d570d21 C tip "C" as 82b8abf9c185
saved backup bundle to $TESTTMP/aborted-editor/.hg/strip-backup/f899f3910ce7-7cab5e15-rebase.hg