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=
> histedit=
>
> [alias]
> tglog = log -G --template "{rev}: {node|short} '{desc}' {branches}\n"
> EOF
$ hg init a
$ cd a
$ echo C1 > C1
$ hg ci -Am C1
adding C1
$ echo C2 > C2
$ hg ci -Am C2
adding C2
$ cd ..
$ hg clone a b
updating to branch default
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg clone a c
updating to branch default
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd b
$ echo L1 > L1
$ hg ci -Am L1
adding L1
$ cd ../a
$ echo R1 > R1
$ hg ci -Am R1
adding R1
$ cd ../b
Now b has one revision to be pulled from a:
$ hg pull --rebase
pulling from $TESTTMP/a
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files (+1 heads)
new changesets 77ae9631bcca
rebasing 2:ff8d69a621f9 "L1"
saved backup bundle to $TESTTMP/b/.hg/strip-backup/ff8d69a621f9-160fa373-rebase.hg
$ hg tglog
@ 3: d80cc2da061e 'L1'
|
o 2: 77ae9631bcca 'R1'
|
o 1: 783333faa078 'C2'
|
o 0: 05d58a0c15dd 'C1'
Re-run:
$ hg pull --rebase
pulling from $TESTTMP/a
searching for changes
no changes found
Abort pull early if working dir is not clean:
$ echo L1-mod > L1
$ hg pull --rebase
abort: uncommitted changes
(cannot pull with rebase: please commit or shelve your changes first)
[20]
$ hg update --clean --quiet
Abort pull early if another operation (histedit) is in progress:
$ hg histedit . -q --commands - << EOF
> edit d80cc2da061e histedit: generate unfinished state
> EOF
Editing (d80cc2da061e), commit as needed now to split the change
(to edit d80cc2da061e, `hg histedit --continue` after making changes)
[240]
$ hg pull --rebase
abort: histedit in progress
(use 'hg histedit --continue' or 'hg histedit --abort')
[20]
$ hg histedit --abort --quiet
Abort pull early with pending uncommitted merge:
$ cd ..
$ hg clone --noupdate c d
$ cd d
$ hg tglog
o 1: 783333faa078 'C2'
|
o 0: 05d58a0c15dd 'C1'
$ hg update --quiet 0
$ echo M1 > M1
$ hg commit --quiet -Am M1
$ hg update --quiet 1
$ hg merge 2
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg pull --rebase
abort: outstanding uncommitted merge
(cannot pull with rebase: please commit or shelve your changes first)
[20]
$ hg update --clean --quiet
Abort pull early with unclean subrepo:
$ echo s = s > .hgsub
$ hg add .hgsub
$ hg init s
$ hg commit -m "generated a subrepo"
$ echo a > s/a
$ hg -R s add s/a
$ hg pull --rebase
abort: uncommitted changes in subrepository "s"
(cannot pull with rebase: please commit or shelve your changes first)
[255]
Invoke pull --rebase and nothing to rebase:
$ cd ../c
$ hg book norebase
$ hg pull --rebase
pulling from $TESTTMP/a
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
new changesets 77ae9631bcca
nothing to rebase - updating instead
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
updating bookmark norebase
$ hg tglog -l 1
@ 2: 77ae9631bcca 'R1'
|
~
pull --rebase --update should ignore --update:
$ hg pull --rebase --update
pulling from $TESTTMP/a
searching for changes
no changes found
pull --rebase doesn't update if nothing has been pulled:
$ hg up -q 1
$ hg pull --rebase
pulling from $TESTTMP/a
searching for changes
no changes found
$ hg tglog -l 1
o 2: 77ae9631bcca 'R1'
|
~
$ cd ..
pull --rebase works when a specific revision is pulled (issue3619)
$ cd a
$ hg tglog
@ 2: 77ae9631bcca 'R1'
|
o 1: 783333faa078 'C2'
|
o 0: 05d58a0c15dd 'C1'
$ echo R2 > R2
$ hg ci -Am R2
adding R2
$ echo R3 > R3
$ hg ci -Am R3
adding R3
$ cd ../c
$ hg tglog
o 2: 77ae9631bcca 'R1'
|
@ 1: 783333faa078 'C2'
|
o 0: 05d58a0c15dd 'C1'
$ echo L1 > L1
$ hg ci -Am L1
adding L1
created new head
$ hg pull --rev tip --rebase
pulling from $TESTTMP/a
searching for changes
adding changesets
adding manifests
adding file changes
added 2 changesets with 2 changes to 2 files
new changesets 31cd3a05214e:770a61882ace
rebasing 3:ff8d69a621f9 "L1"
saved backup bundle to $TESTTMP/c/.hg/strip-backup/ff8d69a621f9-160fa373-rebase.hg
$ hg tglog
@ 5: 518d153c0ba3 'L1'
|
o 4: 770a61882ace 'R3'
|
o 3: 31cd3a05214e 'R2'
|
o 2: 77ae9631bcca 'R1'
|
o 1: 783333faa078 'C2'
|
o 0: 05d58a0c15dd 'C1'
pull --rebase works with bundle2 turned on
$ cd ../a
$ echo R4 > R4
$ hg ci -Am R4
adding R4
$ hg tglog
@ 5: 00e3b7781125 'R4'
|
o 4: 770a61882ace 'R3'
|
o 3: 31cd3a05214e 'R2'
|
o 2: 77ae9631bcca 'R1'
|
o 1: 783333faa078 'C2'
|
o 0: 05d58a0c15dd 'C1'
$ cd ../c
$ hg pull --rebase
pulling from $TESTTMP/a
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files (+1 heads)
new changesets 00e3b7781125
rebasing 5:518d153c0ba3 "L1"
saved backup bundle to $TESTTMP/c/.hg/strip-backup/518d153c0ba3-73407f14-rebase.hg
$ hg tglog
@ 6: 0d0727eb7ce0 'L1'
|
o 5: 00e3b7781125 'R4'
|
o 4: 770a61882ace 'R3'
|
o 3: 31cd3a05214e 'R2'
|
o 2: 77ae9631bcca 'R1'
|
o 1: 783333faa078 'C2'
|
o 0: 05d58a0c15dd 'C1'
pull --rebase only update if there is nothing to rebase
$ cd ../a
$ echo R5 > R5
$ hg ci -Am R5
adding R5
$ hg tglog
@ 6: 88dd24261747 'R5'
|
o 5: 00e3b7781125 'R4'
|
o 4: 770a61882ace 'R3'
|
o 3: 31cd3a05214e 'R2'
|
o 2: 77ae9631bcca 'R1'
|
o 1: 783333faa078 'C2'
|
o 0: 05d58a0c15dd 'C1'
$ cd ../c
$ echo L2 > L2
$ hg ci -Am L2
adding L2
$ hg up 'desc(L1)'
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ hg pull --rebase
pulling from $TESTTMP/a
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files (+1 heads)
new changesets 88dd24261747
rebasing 6:0d0727eb7ce0 "L1"
rebasing 7:c1f58876e3bf "L2"
saved backup bundle to $TESTTMP/c/.hg/strip-backup/0d0727eb7ce0-ef61ccb2-rebase.hg
$ hg tglog
o 8: 6dc0ea5dcf55 'L2'
|
@ 7: 864e0a2d2614 'L1'
|
o 6: 88dd24261747 'R5'
|
o 5: 00e3b7781125 'R4'
|
o 4: 770a61882ace 'R3'
|
o 3: 31cd3a05214e 'R2'
|
o 2: 77ae9631bcca 'R1'
|
o 1: 783333faa078 'C2'
|
o 0: 05d58a0c15dd 'C1'
pull --rebase update (no rebase) use proper update:
- warn about other head.
$ cd ../a
$ echo R6 > R6
$ hg ci -Am R6
adding R6
$ cd ../c
$ hg up 'desc(R5)'
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ hg pull --rebase
pulling from $TESTTMP/a
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files (+1 heads)
new changesets 65bc164c1d9b
nothing to rebase - updating instead
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
updated to "65bc164c1d9b: R6"
1 other heads for branch "default"
$ hg tglog
@ 9: 65bc164c1d9b 'R6'
|
| o 8: 6dc0ea5dcf55 'L2'
| |
| o 7: 864e0a2d2614 'L1'
|/
o 6: 88dd24261747 'R5'
|
o 5: 00e3b7781125 'R4'
|
o 4: 770a61882ace 'R3'
|
o 3: 31cd3a05214e 'R2'
|
o 2: 77ae9631bcca 'R1'
|
o 1: 783333faa078 'C2'
|
o 0: 05d58a0c15dd 'C1'
Multiple pre-existing heads on the branch
-----------------------------------------
Pull bring content, but nothing on the current branch, we should not consider
pre-existing heads.
$ cd ../a
$ hg branch unrelatedbranch
marked working directory as branch unrelatedbranch
(branches are permanent and global, did you want a bookmark?)
$ echo B1 > B1
$ hg commit -Am B1
adding B1
$ cd ../c
$ hg up 'desc(L2)'
2 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ hg pull --rebase
pulling from $TESTTMP/a
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
new changesets 39c381359968
nothing to rebase
There is two local heads and we pull a third one.
The second local head should not confuse the `hg pull rebase`.
$ hg up 'desc(R6)'
1 files updated, 0 files merged, 2 files removed, 0 files unresolved
$ echo M1 > M1
$ hg commit -Am M1
adding M1
$ cd ../a
$ hg up 'desc(R6)'
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ echo R7 > R7
$ hg commit -Am R7
adding R7
$ cd ../c
$ hg up 'desc(L2)'
2 files updated, 0 files merged, 2 files removed, 0 files unresolved
$ hg pull --rebase
pulling from $TESTTMP/a
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files (+1 heads)
new changesets f7d3e42052f9
rebasing 7:864e0a2d2614 "L1"
rebasing 8:6dc0ea5dcf55 "L2"
saved backup bundle to $TESTTMP/c/.hg/strip-backup/864e0a2d2614-2f72c89c-rebase.hg
$ hg tglog
@ 12: 3603a865eea0 'L2'
|
o 11: bcc8a9cd04bf 'L1'
|
o 10: f7d3e42052f9 'R7'
|
| o 9: 41fab4eef82f 'M1'
|/
| o 8: 39c381359968 'B1' unrelatedbranch
|/
o 7: 65bc164c1d9b 'R6'
|
o 6: 88dd24261747 'R5'
|
o 5: 00e3b7781125 'R4'
|
o 4: 770a61882ace 'R3'
|
o 3: 31cd3a05214e 'R2'
|
o 2: 77ae9631bcca 'R1'
|
o 1: 783333faa078 'C2'
|
o 0: 05d58a0c15dd 'C1'