push: rework the computation of fallbackheads to be correct
The previous computation tried to be smart but ended up being wrong. This was
caught by phase movement test while reworking the phase discovery logic to be
faster.
The previous logic was failing to catch case where the pushed set was not based
on a common heads (i.e. when the discovery seemed to have "over discovered"
content, outside the pushed set)
In the following graph, `e` is a common head and we `hg push -r f`. We need to
detect `c` as a fallback heads and we previous failed to do so::
e
|
d f
|/
c
|
b
|
a
The performance impact of the change seems minimal. On the most impacted
repository at hand (mozilla-try), the slowdown seems mostly mixed in the
overall noise `hg push` but seems to be in the hundred of milliseconds order of
magnitude. When using rust, we seems to be a bit faster, probably because we
leverage more accelaratd internals.
I added a couple of performance related common for further investigation later
on.
#require git
$ echo "[core]" >> $HOME/.gitconfig
$ echo "autocrlf = false" >> $HOME/.gitconfig
$ echo "[core]" >> $HOME/.gitconfig
$ echo "autocrlf = false" >> $HOME/.gitconfig
$ cat <<EOF >> $HGRCPATH
> [extensions]
> convert =
> [convert]
> hg.usebranchnames = True
> hg.tagsbranch = tags-update
> EOF
$ GIT_AUTHOR_NAME='test'; export GIT_AUTHOR_NAME
$ GIT_AUTHOR_EMAIL='test@example.org'; export GIT_AUTHOR_EMAIL
$ GIT_AUTHOR_DATE="2007-01-01 00:00:00 +0000"; export GIT_AUTHOR_DATE
$ GIT_COMMITTER_NAME="$GIT_AUTHOR_NAME"; export GIT_COMMITTER_NAME
$ GIT_COMMITTER_EMAIL="$GIT_AUTHOR_EMAIL"; export GIT_COMMITTER_EMAIL
$ GIT_COMMITTER_DATE="$GIT_AUTHOR_DATE"; export GIT_COMMITTER_DATE
$ count=10
$ action()
> {
> GIT_AUTHOR_DATE="2007-01-01 00:00:$count +0000"
> GIT_COMMITTER_DATE="$GIT_AUTHOR_DATE"
> git "$@" >/dev/null 2>/dev/null || echo "git command error"
> count=`expr $count + 1`
> }
$ glog()
> {
> hg log -G --template '{rev} "{desc|firstline}" files: {files}\n' "$@"
> }
$ convertrepo()
> {
> hg convert --datesort git-repo hg-repo
> }
Build a GIT repo with at least 1 tag
$ mkdir git-repo
$ cd git-repo
$ git init >/dev/null 2>&1
$ echo a > a
$ git add a
$ action commit -m "rev1"
$ action tag -m "tag1" tag1
$ cd ..
Convert without tags
$ hg convert git-repo hg-repo --config convert.skiptags=True
initializing destination hg-repo repository
scanning source...
sorting...
converting...
0 rev1
updating bookmarks
$ hg -R hg-repo tags
tip 0:d98c8ad3a4cf
$ rm -rf hg-repo
Do a first conversion
$ convertrepo
initializing destination hg-repo repository
scanning source...
sorting...
converting...
0 rev1
updating tags
updating bookmarks
Simulate upstream updates after first conversion
$ cd git-repo
$ echo b > a
$ git add a
$ action commit -m "rev2"
$ action tag -m "tag2" tag2
$ cd ..
Perform an incremental conversion
$ convertrepo
scanning source...
sorting...
converting...
0 rev2
updating tags
updating bookmarks
Print the log
$ cd hg-repo
$ glog
o 3 "update tags" files: .hgtags
|
| o 2 "rev2" files: a
| |
o | 1 "update tags" files: .hgtags
/
o 0 "rev1" files: a
$ cd ..