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"
$ hg init master
$ cd master
$ cat >> .hg/hgrc <<EOF
> [remotefilelog]
> server=True
> EOF
$ echo x > foo
$ echo y > bar
$ hg commit -qAm one
$ hg tag tag1
$ cd ..
# clone with tags
$ hg clone --shallow ssh://user@dummy/master shallow --noupdate --config remotefilelog.excludepattern=.hgtags
streaming all changes
4 files to transfer, 662 bytes of data (no-zstd !)
transferred 662 bytes in * seconds (* */sec) (glob) (no-zstd !)
4 files to transfer, 665 bytes of data (zstd no-rust !)
transferred 665 bytes in * seconds (* */sec) (glob) (zstd no-rust !)
6 files to transfer, 791 bytes of data (zstd rust !)
transferred 791 bytes in * seconds (*/sec) (glob) (zstd rust !)
searching for changes
no changes found
$ cat >> shallow/.hg/hgrc <<EOF
> [remotefilelog]
> cachepath=$PWD/hgcache
> debug=True
> reponame = master
> excludepattern=.hgtags
> [extensions]
> remotefilelog=
> EOF
$ cd shallow
$ ls .hg/store/data
~2ehgtags.i
$ hg tags
tip 1:6ce44dcfda68
tag1 0:e0360bc0d9e1
$ hg update
3 files updated, 0 files merged, 0 files removed, 0 files unresolved
2 files fetched over 1 fetches - (2 misses, 0.00% hit ratio) over *s (glob)
# pull with tags
$ cd ../master
$ hg tag tag2
$ cd ../shallow
$ hg pull
pulling from ssh://user@dummy/master
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 0 changes to 0 files
new changesets 6a22dfa4fd34
(run 'hg update' to get a working copy)
$ hg tags
tip 2:6a22dfa4fd34
tag2 1:6ce44dcfda68
tag1 0:e0360bc0d9e1
$ hg update
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ ls .hg/store/data
~2ehgtags.i
$ hg log -l 1 --stat
changeset: 2:6a22dfa4fd34
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: Added tag tag2 for changeset 6ce44dcfda68
.hgtags | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)