outgoing: rework the handling of the `missingroots` case to be faster
The previous implementation was slow, to the point it was taking a significant
amount of `hg bundle --type none-streamv2` call. We rework the code to compute
the same value much faster, making the operation disappear from the `hg bundle
--type none-streamv2` profile. Someone would remark that producing a streamclone
does not requires an `outgoing` object. However that is a matter for another
day. There is other user of `missingroots` (non stream `hg bundle` call for
example), and they will also benefit from this rework.
We implement an old TODO in the process, directly computing the missing and
common attribute as we have most element at hand already.
### benchmark.name = hg.command.bundle
# bin-env-vars.hg.flavor = default
# bin-env-vars.hg.py-re2-module = default
# benchmark.variants.revs = all
# benchmark.variants.type = none-streamv2
## data-env-vars.name = heptapod-public-2024-03-25-zstd-sparse-revlog
before: 7.750458
after: 6.665565 (-14.00%, -1.08)
## data-env-vars.name = mercurial-public-2024-03-22-zstd-sparse-revlog
before: 0.700229
after: 0.496050 (-29.16%, -0.20)
## data-env-vars.name = mozilla-try-2023-03-22-zstd-sparse-revlog
before: 346.508952
after: 316.749699 (-8.59%, -29.76)
## data-env-vars.name = pypy-2024-03-22-zstd-sparse-revlog
before: 3.401700
after: 2.915810 (-14.28%, -0.49)
## data-env-vars.name = tryton-public-2024-03-22-zstd-sparse-revlog
before: 1.870798
after: 1.461583 (-21.87%, -0.41)
note: this whole `missingroots` of outgoing has a limited number of callers and
could likely be replace by something simpler (like taking an explicit
"missing_revs" set for example). However this is a wider change and we focus on
a small impact, quick rework that does not change the API for now.
Checking how hg behaves when one side of a pull/push doesn't support
some capability (because it's running an older hg version, usually).
$ hg init repo1
$ cd repo1
$ echo a > a; hg add -q a; hg commit -q -m a
$ hg bookmark a
$ hg clone -q . ../repo2
$ cd ../repo2
$ touch $TESTTMP/disable-lookup.py
$ disable_cap() {
> rm -f $TESTTMP/disable-lookup.pyc # pyc caching is buggy
> cat <<EOF > $TESTTMP/disable-lookup.py
> from mercurial import extensions, wireprotov1server
> def wcapabilities(orig, *args, **kwargs):
> cap = orig(*args, **kwargs)
> cap.remove(b'$1')
> return cap
> extensions.wrapfunction(wireprotov1server, '_capabilities', wcapabilities)
> EOF
> }
$ cat >> ../repo1/.hg/hgrc <<EOF
> [extensions]
> disable-lookup = $TESTTMP/disable-lookup.py
> EOF
$ hg pull ssh://user@dummy/repo1 -r tip -B a
pulling from ssh://user@dummy/repo1
no changes found
$ disable_cap lookup
$ hg pull ssh://user@dummy/repo1 -r tip -B a
pulling from ssh://user@dummy/repo1
abort: other repository doesn't support revision lookup, so a rev cannot be specified.
[255]
$ disable_cap pushkey
$ hg pull ssh://user@dummy/repo1 -r tip -B a
pulling from ssh://user@dummy/repo1
abort: remote bookmark a not found!
[10]