evolve: handle relocation during divergence resolution producing no changes
When resolving divergence and the two divergent commits have different
parents, we start by rebasing one of them to have the same parent as
the other. That step can result in no changes to commit. When it does,
we would crash with a TypeError before this patch.
This patch fixes it by instead creating an empty commit in that
scenario. The existing code then continues to attempt to merge it,
which produces no changes, and no commit is created on top. The other
side of the divergence is marked as successor as usual, so orphans
from the side that became empty will be evolved to the right place
(see test).
=========================================
Testing single head enforcement: Case A-1
=========================================
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 1: obsoleting a merge reveal two heads
.. old-state:
..
.. * 3 changeset changeset on branch default (2 on their own branch + 1 merge)
.. * 1 changeset on branch Z (children of the merge)
..
.. new-state:
..
.. * 2 changeset changeset on branch default (merge is obsolete) each a head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:
..
.. D ● (branch Z)
.. |
.. C ● (branch Z)
.. |
.. M ⊗
.. |\
.. A ● ● B
.. |/
.. ●
$ . $TESTDIR/testlib/topic_setup.sh
$ . $TESTDIR/testlib/push-checkheads-util.sh
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
(consider using topic for lightweight branches. See 'hg help topic')
$ 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 up 0
0 files updated, 0 files merged, 3 files removed, 0 files unresolved
$ mkcommit A1
created new head
(consider using topic for lightweight branches. See 'hg help topic')
$ mkcommit B1
$ hg debugobsolete `getid "desc(M0)"` --record-parents
1 new obsolescence markers
obsoleted 1 changesets
1 new orphan changesets
$ hg log -G --hidden
@ 262c8c798096 [default] (draft): B1
|
o f6082bc4ffef [default] (draft): A1
|
| * 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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