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.
#!/bin/bash
set -eu
if [[ "$PHABRICATOR_TOKEN" == "NO-PHAB" ]]; then
echo 'Skipping Phabricator Step' >&2
exit 0
fi
revision_in_stack=`hg log \
--rev '.#stack and ::. and topic()' \
-T '\nONE-REV\n' \
| grep 'ONE-REV' | wc -l`
revision_on_phab=`hg log \
--rev '.#stack and ::. and topic() and desc("re:\nDifferential Revision: [^\n]+D\d+$")'\
-T '\nONE-REV\n' \
| grep 'ONE-REV' | wc -l`
if [[ $revision_in_stack -eq 0 ]]; then
echo "stack is empty" >&2
exit 0
fi
if [[ $revision_on_phab -eq 0 ]]; then
echo "no tracked diff in this stack" >&2
exit 0
fi
if [[ $revision_on_phab -lt $revision_in_stack ]]; then
echo "not all stack changesets (${revision_in_stack}) have matching Phabricator Diff (${revision_on_phab})" >&2
exit 2
fi
if [[ "$PHABRICATOR_TOKEN" == "" ]]; then
echo 'missing $PHABRICATOR_TOKEN variable' >&2
echo '(use PHABRICATOR_TOKEN="NO-PHAB" to disable this step)' >&2
exit 2
fi
hg \
--config extensions.phabricator= \
--config phabricator.url=https://phab.mercurial-scm.org/ \
--config phabricator.callsign=HG \
--config auth.phabricator.schemes=https \
--config auth.phabricator.prefix=phab.mercurial-scm.org \
--config auth.phabricator.phabtoken=$PHABRICATOR_TOKEN \
phabsend --rev '.#stack and ::. and topic()' \
"$@"