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.
====================================
Testing head checking code: Case E-3
====================================
Mercurial checks for the introduction of new heads on push. Evolution comes
into play to detect if existing branches on the server are being replaced by
some of the new one we push.
This case is part of a series of tests checking this behavior.
Category E: case involving changeset on multiple branch
TestCase 8: moving only part of the interleaved branch away, creating 2 heads
.. old-state:
..
.. * 2-changeset on branch default
.. * 1-changeset on branch Z (between the two other)
..
.. new-state:
..
.. * 2-changeset on branch default, on untouched, the other moved
.. * 1-changeset on branch Z (at the same location)
..
.. expected-result:
..
.. * push rejected
..
.. graph-summary:
..
.. C ø⇠◔ C'
.. | |
.. B ◔ |
.. | |
.. A ◔ |
.. |/
.. ●
$ . $TESTDIR/testlib/push-checkheads-util.sh
Test setup
----------
$ mkdir E1
$ cd E1
$ setuprepos
creating basic server and client repo
updating to branch default
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd client
$ hg branch Z
marked working directory as branch Z
(branches are permanent and global, did you want a bookmark?)
$ mkcommit B0
$ hg branch default --force
marked working directory as branch default
$ mkcommit C0
created new head
$ hg push --new-branch
pushing to $TESTTMP/E1/server
searching for changes
adding changesets
adding manifests
adding file changes
added 2 changesets with 2 changes to 2 files
$ hg up 0
0 files updated, 0 files merged, 3 files removed, 0 files unresolved
$ mkcommit C1
created new head
$ hg debugobsolete `getid "desc(C0)" ` `getid "desc(C1)"`
1 new obsolescence markers
obsoleted 1 changesets
$ hg log -G --hidden
@ dc44c53142f0 (draft): C1
|
| x afc55ba2ce61 (draft): C0
| |
| o 93e5c1321ece (draft): B0
| |
| o 8aaa48160adc (draft): A0
|/
o 1e4be0697311 (public): root
Actual testing
--------------
$ hg push -r 'desc("C1")'
pushing to $TESTTMP/E1/server
searching for changes
abort: push creates new remote head dc44c53142f0
(merge or see 'hg help push' for details about pushing new heads)
[20]
$ cd ../..