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
Verify that pending changesets are seen by pretxn* hooks but not by other
processes that access the destination repo while the hooks are running.
The hooks (python and external) both reject changesets after some think time,
during which another process runs pull. Each hook creates a file ('notify') to
indicate to the controlling process that it is running; the process removes the
file to indicate the hook can terminate.
init env vars
$ d=`pwd`
$ maxwait=20
utility to run the test - start a push in the background and run pull
$ dotest() {
> rm -f notify
> printf 'push '; hg -R child-push tip --template '{node}\n'
> hg -R child-push -q push > push.out 2>&1 &
>
> # wait for hook to create the notify file
> i=$maxwait
> while [ ! -f notify -a $i != 0 ]; do
> sleep 1
> i=`expr $i - 1`
> done
>
> # run pull
> hg -R child-pull -q pull
> rc=$?
>
> # tell hook to finish; notify should exist.
> rm notify
> wait
>
> cat push.out
> printf 'pull '; hg -R child-pull tip --template '{node}\n'
> return $rc
> }
python hook
$ cat <<EOF > reject.py
> import os
> import time
> def rejecthook(ui, repo, hooktype, node, **opts):
> ui.write(b'hook %s\\n' % repo[b'tip'].hex())
> # create the notify file so caller knows we're running
> fpath = os.path.join('$d', 'notify')
> f = open(fpath, 'w')
> f.close()
> # wait for ack - caller should delete the notify file
> i = int("$maxwait")
> while os.path.exists(fpath) and i > 0:
> time.sleep(1)
> i -= 1
> return True # reject the changesets
> EOF
external hook
$ cat <<EOF > reject.sh
> printf 'hook '; hg tip --template '{node}\\n'
> # create the notify file so caller knows we're running
> fpath=$d/notify
> touch \$fpath
> # wait for ack - caller should delete the notify file
> i=$maxwait
> while [ -f \$fpath -a \$i != 0 ]; do
> sleep 1
> i=\`expr \$i - 1\`
> done
> exit 1 # reject the changesets
> EOF
create repos
$ hg init parent
$ hg clone -q parent child-push
$ hg clone -q parent child-pull
$ echo a > child-push/a
$ hg -R child-push add child-push/a
$ hg -R child-push commit -m a -d '1000000 0'
test python hook
$ cat <<EOF > parent/.hg/hgrc
> [extensions]
> reject = $d/reject.py
> [hooks]
> pretxnchangegroup = python:reject.rejecthook
> EOF
$ dotest
push 29b62aeb769fdf78d8d9c5f28b017f76d7ef824b
hook 29b62aeb769fdf78d8d9c5f28b017f76d7ef824b
transaction abort!
rollback completed
abort: pretxnchangegroup hook failed
pull 0000000000000000000000000000000000000000
test external hook
$ cat <<EOF > parent/.hg/hgrc
> [hooks]
> pretxnchangegroup = sh $d/reject.sh
> EOF
$ dotest
push 29b62aeb769fdf78d8d9c5f28b017f76d7ef824b
hook 29b62aeb769fdf78d8d9c5f28b017f76d7ef824b
transaction abort!
rollback completed
abort: pretxnchangegroup hook exited with status 1
pull 0000000000000000000000000000000000000000
Test that pending on transaction without changegroup see the normal changegroup(
(issue4609)
$ cat <<EOF > parent/.hg/hgrc
> [hooks]
> pretxnchangegroup=
> pretxnclose = hg tip -T "tip: {node|short}\n"
> [phases]
> publishing=False
> EOF
setup
$ cd parent
$ echo a > a
$ hg add a
$ hg commit -m a
tip: cb9a9f314b8b
actual test
$ hg phase --public .
tip: cb9a9f314b8b