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 single head enforcement: Case A-5
=========================================
A repository is set to only accept a single head per name (typically named
branch). However, obsolete changesets can make this enforcement more
complicated, because they can be kept visible by other changeset on other
branch.
This case is part of a series of tests checking this behavior.
Category A: Involving obsolescence
TestCase 5: Obsoleting a merge reveals two heads
.. old-state:
..
.. * 3 changesets on branch default (2 on their own branch + 1 merge)
.. * 1 changeset on branch Z (children of the merge)
..
.. new-state:
..
.. * 2 changesets on branch default (merge is obsolete) each a head
.. * 1 changeset on branch Z keeping the merge visible
..
.. expected-result:
..
.. * 2 heads detected (because we skip the merge)
..
.. graph-summary:
..
.. C ● (branch Z)
.. |
.. M ⊗
.. |\
.. A ● ● B
.. |/
.. ●
$ . $TESTDIR/testlib/push-checkheads-util.sh
$ cat >> $HGRCPATH << EOF
> [command-templates]
> log = "{node|short} [{branch}] ({phase}): {desc}\n"
> EOF
Test setup
----------
$ mkdir A5
$ cd A5
$ setuprepos single-head
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 up 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ mkcommit B0
created new head
$ hg merge
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg ci -m 'M0'
$ hg branch Z
marked working directory as branch Z
(branches are permanent and global, did you want a bookmark?)
$ mkcommit C0
$ hg push --new-branch
pushing to $TESTTMP/A5/server
searching for changes
adding changesets
adding manifests
adding file changes
added 3 changesets with 2 changes to 2 files
$ hg debugobsolete `getid "desc(M0)"` --record-parents
1 new obsolescence markers
obsoleted 1 changesets
1 new orphan changesets
$ hg heads
61c95483cc12 [Z] (draft): C0
74ff5441d343 [default] (draft): B0
8aaa48160adc [default] (draft): A0
$ hg log -G --hidden
@ 61c95483cc12 [Z] (draft): C0
|
x 14d3d4d41d1a [default] (draft): M0
|\
| o 74ff5441d343 [default] (draft): B0
| |
o | 8aaa48160adc [default] (draft): A0
|/
o 1e4be0697311 [default] (public): root
Actual testing
--------------
(force push to make sure we get the changeset on the remote)
$ hg push -r 'desc("C0")' --force
pushing to $TESTTMP/A5/server
searching for changes
no changes found
transaction abort!
rollback completed
abort: rejecting multiple heads on branch "default"
(2 heads: 8aaa48160adc 74ff5441d343)
[255]