branchcache: add a "pure topological head" fast path
In a narrow but actually quick common case, all topological heads are all on
the same branch and all open. In this case, computing the branch map is very
simple. We can quickly detect situation where this situation will not change.
So we update the V3 format to be able to express this situation and upgrade the
update code to detect we remains in that mode.
The branch cache is populated with the actual value when the branch map is
accessed, but the update_disk method can do the update without needing to
populate it.
=========================================
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 * 2 changesets on branch default (merge is obsolete) each a head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)
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