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]
> convert=
> [convert]
> hg.saverev=False
> EOF
$ hg init orig
$ cd orig
$ echo foo > foo
$ echo bar > bar
$ hg ci -qAm 'add foo bar' -d '0 0'
$ echo >> foo
$ hg ci -m 'change foo' -d '1 0'
$ hg up -qC 0
$ hg copy --after --force foo bar
$ hg copy foo baz
$ hg ci -m 'make bar and baz copies of foo' -d '2 0'
created new head
Test that template can print all file copies (issue4362)
$ hg log -r . --template "{file_copies % ' File: {file_copy}\n'}"
File: bar (foo)
File: baz (foo)
$ hg bookmark premerge1
$ hg merge -r 1
merging baz and foo to baz
1 files updated, 1 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg ci -m 'merge local copy' -d '3 0'
$ hg up -C 1
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
(leaving bookmark premerge1)
$ hg bookmark premerge2
$ hg merge 2
merging foo and baz to baz
1 files updated, 1 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg ci -m 'merge remote copy' -d '4 0'
created new head
Make and delete some tags
$ hg tag that
$ hg tag --remove that
$ hg tag this
#if execbit
$ chmod +x baz
#else
$ echo some other change to make sure we get a rev 5 > baz
#endif
$ hg ci -m 'mark baz executable' -d '5 0'
$ cd ..
$ hg convert --datesort orig new 2>&1 | grep -v 'subversion python bindings could not be loaded'
initializing destination new repository
scanning source...
sorting...
converting...
8 add foo bar
7 change foo
6 make bar and baz copies of foo
5 merge local copy
4 merge remote copy
3 Added tag that for changeset 8601262d7472
2 Removed tag that
1 Added tag this for changeset 706614b458c1
0 mark baz executable
updating bookmarks
$ cd new
$ hg out ../orig
comparing with ../orig
searching for changes
no changes found
[1]
#if execbit
$ hg bookmarks
premerge1 3:973ef48a98a4
premerge2 8:c4968fdf2e5d
#else
Different hash because no x bit
$ hg bookmarks
premerge1 3:973ef48a98a4
premerge2 8:1cc21e701444
#endif
Test that redoing a convert results in an identical graph
$ cd ../
$ rm new/.hg/shamap
$ hg convert --datesort orig new 2>&1 | grep -v 'subversion python bindings could not be loaded'
scanning source...
sorting...
converting...
8 add foo bar
7 change foo
6 make bar and baz copies of foo
5 merge local copy
4 merge remote copy
3 Added tag that for changeset 8601262d7472
2 Removed tag that
1 Added tag this for changeset 706614b458c1
0 mark baz executable
updating bookmarks
$ hg -R new log -G -T '{rev} {desc}'
o 8 mark baz executable
|
o 7 Added tag this for changeset 706614b458c1
|
o 6 Removed tag that
|
o 5 Added tag that for changeset 8601262d7472
|
o 4 merge remote copy
|\
+---o 3 merge local copy
| |/
| o 2 make bar and baz copies of foo
| |
o | 1 change foo
|/
o 0 add foo bar
check shamap LF and CRLF handling
$ cat > rewrite.py <<EOF
> import sys
> # Interlace LF and CRLF
> lines = [(l.rstrip() + ((i % 2) and b'\n' or b'\r\n'))
> for i, l in enumerate(open(sys.argv[1], 'rb'))]
> open(sys.argv[1], 'wb').write(b''.join(lines))
> EOF
$ "$PYTHON" rewrite.py new/.hg/shamap
$ cd orig
$ hg up -qC 1
$ echo foo >> foo
$ hg ci -qm 'change foo again'
$ hg up -qC 2
$ echo foo >> foo
$ hg ci -qm 'change foo again again'
$ cd ..
$ hg convert --datesort orig new 2>&1 | grep -v 'subversion python bindings could not be loaded'
scanning source...
sorting...
converting...
1 change foo again again
0 change foo again
updating bookmarks
init broken repository
$ hg init broken
$ cd broken
$ echo a >> a
$ echo b >> b
$ hg ci -qAm init
$ echo a >> a
$ echo b >> b
$ hg copy b c
$ hg ci -qAm changeall
$ hg up -qC 0
$ echo bc >> b
$ hg ci -m changebagain
created new head
$ HGMERGE=internal:local hg -q merge
$ hg ci -m merge
$ hg mv b d
$ hg ci -m moveb
break it
#if reporevlogstore
$ rm .hg/store/data/b.*
#endif
#if reposimplestore
$ rm .hg/store/data/b/*
#endif
$ cd ..
$ hg --config convert.hg.ignoreerrors=True convert broken fixed
initializing destination fixed repository
scanning source...
sorting...
converting...
4 init
ignoring: data/b@1e88685f5ddec574a34c70af492f95b6debc8741: no match found (reporevlogstore !)
ignoring: data/b/index@1e88685f5dde: no node (reposimplestore !)
3 changeall
2 changebagain
1 merge
0 moveb
$ hg -R fixed verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
checked 5 changesets with 5 changes to 3 files
manifest -r 0
$ hg -R fixed manifest -r 0
a
manifest -r tip
$ hg -R fixed manifest -r tip
a
c
d
$ cd ..
$ hg init commit-references
$ cd commit-references
$ echo a > a
$ hg ci -Aqm initial
$ echo b > b
$ hg ci -Aqm 'the previous commit was 1451231c8757'
$ echo c > c
$ hg ci -Aqm 'the working copy is called ffffffffffff'
$ cd ..
$ hg convert commit-references new-commit-references -q \
> --config convert.hg.sourcename=yes
$ cd new-commit-references
$ hg log -T '{node|short} {desc}\n'
fe295c9e6bc6 the working copy is called ffffffffffff
642508659503 the previous commit was c2491f685436
c2491f685436 initial