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 no-windows
$ . "$TESTDIR/remotefilelog-library.sh"
Set up an extension to make sure remotefilelog clientsetup() runs
unconditionally even if we have never used a local shallow repo.
This mimics behavior when using remotefilelog with chg. clientsetup() can be
triggered due to a shallow repo, and then the code can later interact with
non-shallow repositories.
$ cat > setupremotefilelog.py << EOF
> from mercurial import extensions
> def extsetup(ui):
> remotefilelog = extensions.find(b'remotefilelog')
> remotefilelog.onetimeclientsetup(ui)
> EOF
Set up the master repository to pull from.
$ hg init master
$ cd master
$ cat >> .hg/hgrc <<EOF
> [remotefilelog]
> server=True
> EOF
$ echo x > x
$ hg commit -qAm x
$ cd ..
$ hg clone ssh://user@dummy/master child -q
We should see the remotefilelog capability here, which advertises that
the server supports our custom getfiles method.
$ cd master
$ echo 'hello' | hg -R . serve --stdio | grep capa | identifyrflcaps
exp-remotefilelog-ssh-getfiles-1
x_rfl_getfile
x_rfl_getflogheads
$ echo 'capabilities' | hg -R . serve --stdio | identifyrflcaps ; echo
exp-remotefilelog-ssh-getfiles-1
x_rfl_getfile
x_rfl_getflogheads
Pull to the child repository. Use our custom setupremotefilelog extension
to ensure that remotefilelog.onetimeclientsetup() gets triggered. (Without
using chg it normally would not be run in this case since the local repository
is not shallow.)
$ echo y > y
$ hg commit -qAm y
$ cd ../child
$ hg pull --config extensions.setuprfl=$TESTTMP/setupremotefilelog.py
pulling from ssh://user@dummy/master
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
new changesets d34c38483be9
(run 'hg update' to get a working copy)
$ hg up
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cat y
y
Test that bundle works in a non-remotefilelog repo w/ remotefilelog loaded
$ echo y >> y
$ hg commit -qAm "modify y"
$ hg bundle --base ".^" --rev . mybundle.hg --config extensions.setuprfl=$TESTTMP/setupremotefilelog.py
1 changesets found
$ cd ..